Cozy Beehive

Factors Affecting Bicycle Transmission Efficiency

noreply@blogger.com (Ron) — Mon, 16 Jan 2012 02:32:00 +0000

Recently I had been thinking about what kind of gear ratios I would need to climb Mount Washington on my derailleur equipped bike. Being an engineer, efficiency is a staple word in my daily mingling with other engineers.

So I started to think about gear to gear effect on a multi speed road bike, such as one with 30 speeds (3 gears up front, 10 in the back). If one could save a bit of power by choosing the most mechanically efficient gearing, that'd be a relief on a long climb (lesser energy expenditure) and could translate into quicker times.

Most people you talk to about this subject would snap that the well oiled bicycle chain is 98% efficient and the discussion would end there. However, missing from that discussion is several factors that could skew it one way or the other.

One factor may be obvious - chain tension. If the chain is too long for the job, the slack side tension is now more, which will subtract from the tight side tension in the power equation. You wont be riding for a long time this way because there is higher tendency for the chain to 'jump' or skip gears. Efficiency for a given cadence will be lower.

The second factor is the selected gear. When you move away from a single speed setup and loop your chain through a derailleur and a cog containing several sprockets, efficiency is not really constant per se from gear to gear. Some gears happen to be more efficient than others, perhaps because of what you can call lesser system 'restrictions'.

If you picture yourself as a link on the chain and think about the challenge of having to maintain chain tension while bending around big and small gears alike, you'd carry power more easily the lesser you'd have to twist and bend. Atleast that's my theory. I'd like to think that a 11T small cog presents a bigger restriction to chain-link movement than a 17T cog.

Other things are less obvious. What could the effect on drivetrain wear be? I've written about an effect called chordal action when using high gears.

To measure gear to gear efficiency loss with any degree of high accuracy takes a dyno setup, load cells, a data acquisition system and lots of time. Fortunately, Chester Kyle, a mechanical engineering professor at Cal State Long Beach and founding father of IHPVA, did some very relevant work on this stuff back in the day. In Vol 52-2001 of the Human Power magazine, he describes using a single setup, with varying loads to measure efficiency in multiple drivetrain systems including hub gears.

Some of the findings were -

1) Efficiency generally increased with load : As you drive the crank to higher power inputs, the frictional factors eating away at that input becomes a lesser percentage as the input goes up. So frictional effects go up less rapidly. (Ofcourse, we're talking about mechanical efficiency here. If the human body is less efficient at oxygen intake and clearing away lactate at higher loads, there's really no point in trying to hammer away with higher gears. But that's a subject for another day)

2) There is generally a 1-3% difference in efficiency between adjacent gears. Prof. Kyle wrote that "an average of 2% difference in efficiency is thus easily possible if the wrong gears are chosen".

3) The efficiency (for all loads tested) tends to fall with higher gear ratios for all transmission systems tested.

Since I was thinking about my own road bike setup, I was particularly interested in the test he performed on the 27 speed Shimano system. The efficiency curve for this setup looked like this from the study :

A Shimano Ultegra 27-speed mountain- bike transmission with three front chainrings (44/32/22 teeth) and a 9-speed rear cluster (12, 14, 16, 18, 20, 23, 26, 30, and 34 teeth). Input cadence is constant at 75 rpm. Driven load power selected were 80 W, 150 W and 200 W. Dotted trend line shows average efficiency of setup tested at all loads decreasing with gear number.

Since Prof. Kyle ran out of time, only 15 of the 27 gears were tested.

I constructed the legend of the data points below. Gear ratio, calculated as driven teeth divided by driving teeth, decreases from top to bottom. Smaller gear ratio means "high gear" while the opposite is "low gear". Generally, the former is important if you wanted top speed and the latter would be if you cared for acceleration.

The graph show interesting things and I'd like to highlight a couple that caught my eye:

1) I'm seeing that higher gears and hence lower gear ratios mean you can lose efficiency but some perspective is important here. Between the lowest gear and the highest gears tested in this setup, there's a 1 point drop in average efficiency.

2) The 44/34T gear, which is a big front-big rear cross chained scenario, shows the worst efficiency. Generally, cross chaining is not a good thing so this might be the proof of that.

3) The 44/12T gear, which is a big front-small rear cross chained scenario interestingly shows about the same efficiency at 75 rpm as a 44/26T. Why is this so, given that I said driving a chain around a smaller cog is probably worse for transmission efficiency? No idea. Perhaps its more straight chained than the latter. Moreover, this type of cross chaining shows higher efficiency than a big-front-big rear cross chain.

4) 44/20T shows the highest efficiency of 95%, and if you included the 1-2% in friction loses in Prof. Kyle's study, that translates to 96-97% efficiency.. It must be straight chained as well. Could anyone verify this?

This study is truly interesting and has implications for performance improvement. I wonder if anyone else from another part of the world had a chance to investigate this more. It paves way for some interesting discussion.

CONNECTED READING :

52/12T vs 52/11T Gearing : A Look At Chordal Action

* * *

Electronically Balanced Bicycles & Unicycles

noreply@blogger.com (Ron) — Sat, 31 Dec 2011 00:40:00 +0000

"..The wheel consists of a ring of small rubber wheels overlapping a single large wheel. When the large wheel rotates, the U3-X moves forward or backward.."

Hundreds of years ago and approaching the Industrial Revolution, we had all sorts of genius and madmen tinkering with devices to propel an age of moving devices by virtue of mechanics. Plethora of gears, linkages and energy conversion schemes gave us the printing press, the mechanical wristwatch, the steam engine, the bicycle and calculators.

We're now quite deeply embedded in the Age of Electronics, where smart, sensible electronics in the form of boards, kits, controllers, sensors etc seem to be well within the affordability of average Joe. Has the age of invention really died? I argue not. Did you check next door?

Anyway...there is something existential in seeing a machine able to balance itself, isn't it? Well that's the topic for today.

Some years back while in college, I saw the murata boy riding his bicycle and smirked - that's it, the Japanese are going to take over the world. The motto behind the design effort was 'when you fall off a bicycle, get right back on' and so Murata Manufacturing packed gyro tilt angle sensors, power giving capacitors and other position sensing hardware into the robot to ride a bike. Two wheels.

To give company to the 'male' robot came an agile murata 'girl' and her stance was on one wheel saying 'ha, look at me' and out she came out more looking more heroic than her cousin balancing a unicycle while managing to avoid obstacles.

A video from Hacked Gadgets shows the impressive capabilities of the two creations.

The principles behind these electronics for basic work are not that hard to understand. And for an average guy to get his hands wet in application, you don't have to go far these days. LEGO has for a number of years been marketing the Mindstorms NXT kit which comes with a microprocessor, motors and several sensors to teach you motor control, object detection and so on.

Then if you listened to Cornell prof. Andy Ruina's wise words and had an itch to create, you could take that NXT to the next level :

Elsewhere, people were doing challenging work. The question probably was - could you extend this idea of robot-ism to humans and create a unicycle for propulsion? Dean Kaman's Segway seems to have inspired a string of inventors from all over the world to do exactly that.

The concept would be similar to the Segway - so you would take a chassis and mount an electronic gyroscope capable of measuring vertical angle. If you leaned far forward or back, an electronic motor controller would send a signal to the motor to rev it up or slow down so as to to put the bike back in balance.

The challenge would be to get your filtering right or you'll be leaning forwards and the sluggish machine would toss you off, or there would be introduction of positional errors, gyroscopic "drift" in your system and so on which would also not be good for tracking. Sampling rate is the other thing that's quite important. 100 Hz means sampling every .01 seconds, but on an electric unicycle, is that good enough?

An electrical engineer from Slovenia seemed to have got it right with his Enicycle. Works quite like a Segway and if you wanted to turn left or right, you simply put pressure on the left or right side footrests, then watched where you were going as the 1000 W motor raced the device to 15 kmph. A prototype was featured on the Gadget Show :

Perhaps Honda didn't want to run out of publicity as well and displayed the Honda U3-X, also a personal mobility electric unicycle, to a throng of reporters in Tokyo (2009-ish).

The uninteresting bit was, yeah they had tilt sensors for balance control and so on. What really captivates is the portability of the machine - the bit looks like a sleek boombox and you can haul it around like a pullman. And then came the closely guarded "omnidirectional wheel" in the device.What was that?

A writer for the electronics journal IEEE described the legend of the wheel as such : 'The wheel consists of a ring of small rubber wheels overlapping a single large wheel. When the large wheel rotates, the U3-X moves forward or backward. When the small wheels rotate, the machine moves left or right. And when both the large and small wheels turn at the same time, the U3-X moves diagonally." How does Honda come up with stuff like this?

So here's that video demonstration that Honda did for IEEE reporter in NY. Its a good one.

Focus Designs from Washington was probably inspired by the Enicycle to create something very similar - the SBU (self balancing unicycle). Other than the fact that it costs 1400 cold cash, it can go 12 miles single charge with its 1000W motor and has the capacity for regenerative braking, something I'll have to look more into to assess its potential. (In the past, I wrote a post looking into the regenerative capabilities of MIT's Copenhagen Wheel)

Stephen Boyer, a computer science student at MIT also flexed his creative muscles to see what he can come up with. He validates the fact that anyone these days with decent electronics knowledge can make a forward-backward balancing unicycle. He didn't complete his project since he was unsuccessful at sideways balancing but he's brought some fresh ideas into the picture, like a pressure actuated killswitch that the rider would hold in his hand to kill the machine. Lots more interesting details into the engineering of his "Bullet" and a video of Stephen riding that bike can be found on his blog entry.

Steve Jobs may have passed on with a final look at an iPhone. And Segway's owner J. Heselden may have met his end over a cliff riding a Segway. But these individuals and technologies inspire hundreds of derivative technologies daily. But some part of me wants to see progress from investigative tinkering.

I can't wait for the day when the local pizza joint dishes away with their automobiles and hires a Murata Girl to deliver my pizza. Boy, I think if Google cars can drive around Nevada for 200,000 miles without a single accident, perhaps robots on electric unicycles can do a better job of delivering pizza without fatality. I mean, I do think of how many kittens were killed in the process of getting my pizza, you know.

Happy new year! Here's hoping we see more interesting things in 2012.

* * *

RELATED RESOURCES ON THIS BLOG :

Energy Costs of Riding a Unicycle

Four Part Series On Bicycle Stability
An All-Automatic CVT Based Bicycle

Merry Christmas & A Fabulous New Year

noreply@blogger.com (Ron) — Sun, 25 Dec 2011 16:18:00 +0000

Readers,

After I got hired by Cummins to help engineer/integrate their turbochargers to diesel engines earlier this year, I haven't had much time to concentrate on the blogging aspect. I'm still as passionate about cycling as I ever was, infact I try to commute the 6 miles to work in cold temperatures whenever I can. And I try to ride with colleagues from work.

Here's hoping you all have a joyous Christmas and new year. If it weren't for Christmas, we'd all be Jewish right? Na just kidding. Speaking of Jewish, happy Hanukkah! And Boxing Day to you rest of the bunch, whatever floats your boat.

Hopefully I can kickstart 2012 with some fresh articles relevant to cycling. Keep the rubber side down. Cheers.

-Ron George
Columbus, Indiana

Self Inflating Bicycle Tire Shows Up Again

noreply@blogger.com (Ron) — Mon, 29 Aug 2011 03:08:00 +0000

William Powers, a team member of a new start-up group called PumpTire LLC, informed me a few days ago of their self inflating tire idea. James of Bicycle Design had posted on his blog that he received the same email as well so I figure that this made the rounds to many bloggers in a mass email.

The idea appears to be the brainchild of Benjamin Krempel. The internet describes him as a CEO of Aqueduct Medical, a company that develops "safe, effective, user-friendly products that improve patient recovery from facial and cosmetic surgical procedures."

In the video below, he describes the idea (although somewhat vaguely) :

So its basically a pump that operates every time its squished by rolling motion. "The tire is a 26” x 1.5” tire with a set pressure valve", says the product website. Reportedly, the tire inflates from zero guage pressure. "The pumping mechanism will pump from a flat up to 65psi."

In a blog entry back in 2008, I listed some "new" cycling ideas that would be serve as cool thought experiments, without exploring any technical or economic aspects. An "on the go tire inflation/deflation system" was first on my list and it had an almost science fiction aspect to it - the idea that the tire would have a feedback system to it to monitor pressure while riding and adjust itself after sampling pressure.

One application where this would be attractive is in public bicycles used for bike share programs where a self inflating mechanism could possibly add to some convenience. It avoids the necessity of adding an extra infrastructure for pumping air by the sidewalk or the need for individuals to carry pumps. For utility cyclists, terms like "rolling resistance" or "wheel inertia" are usually unimportant. Most just want to get from point A to B.

Having said that, a safety feature in the system is a must. The tire shouldn't injest water along with air. It also shouldn't over-pressurize and lead to tire bursts. Things like that. In the end, an interesting thought experiment ends up consuming time being developed, tested, re-tested, re-designed, at the same time needing to raise funds for the development and meeting the demands of consumer standards and regulations. By the end of it all, the inventor will want to go for a serious ride to breathe some air.

The idea of a self-inflating tire doesn't appear to have sprung up now. A few others tried to do something on similar lines, one of them if I remember correctly was an entry for the Specialized : Innovate-or-die" contest that happened a few years ago.

Here's Sean Conley back in 2007 :

And here's Kevin Manning, also in 2007 :

Both appear to charge air into the tire through pedaling. A bunch of patents on "self-inflating" tires for cars and bicycles date back to 1800's. Those can be found by a Google Patent search. That's what happens when you give people too much leisure time.

Whether Krempel actually first came up with the idea or not is not the issue. The big picture as I see is perhaps that of the slow march of the bicycle towards fulfilling an intelligent, self correcting system. Automobiles, ships and airplanes are already there but the "control architectures" in these complex systems are the by-product of externally driven factors - federal laws or economic incentives. Will the bicycle really benefit from that kind of intelligence? Sounds like a philosophical question.

* * *

Heat Wave, Gas Laws & Your Bike Tire

noreply@blogger.com (Ron) — Thu, 11 Aug 2011 04:25:00 +0000

Staying cool out there?

Most of us have gone through or are still experiencing the 'heat wave' here in the United States. Temperatures in some places have taken on record proportions. I remember sweating absolute buckets in mid-July here in Western New York. The same route that I have biked for the past 2 years made me more uncomfortable than I ever remember in memory. Some other friends reported sweating Gatorade colored perspiration. I wonder , gee hows that for perspective?

Interestingly, in the midst of the debt crisis, a report from NYT probably slipped by quietly. It wrote that this past July was the 4th warmest on record in the United States according to NOAA studies. That should come as a surprise only to those who still wish to have their heads in the sand about climate change. I mean, the IPCC reports on the global warming phenomenon don't cost a squat and still out there for anyone to read. 20-30 years from now, I wonder whether the idea of a long bicycle ride will bear new meaning as riders struggle to stay cool.

Anyway having said this, there's a certain friend of mine, (who is a bit naive when it comes to bike technicalities), who pumps his tires to their absolute limits before his rides. It is a religious act for him. It does not satisfy him if its 139 psi. He needs all 140 in his pocket! Its as if his bike wouldn't move an inch if he hasn't dialed exactly that number into his tires.

I do keep wondering from time to time whether this has anything to do with the obscenely high number of flat tires he has obtained particularly during this summer. He's told me that he's not had this many in a long time and he's getting frustrated! Well, could one of his problems be that laser focused air pumping addiction?

When you pump air into your tire and go out for a ride, things change inside that tire that you normally would not think of. If I actually believed that he would actually be even remotely interested in some basic math, I would tell him about two beautiful thermodynamic relationships discovered by a bunch of cool people in the 17th and 18th centuries.

In the early 1600's, Robert Boyle sad that the pressure of a gas is inversely proportional to its volume, if temperature is kept constant.

A century later, Joseph Gay-Lussac asserted that pressure of a gas is also directly proportional to its temperature, if volume is kept constant.

The former shows a hyperbolic relationship between pressure and volume, the latter a linear relation between pressure and temperature.

Mathematically, these relationships can be expressed thus :

If you'd put them both together and assumed that your tire volume remains the same while riding, it can be said :

where P1, T1 are pressure and temperature at one instance in time and P2 and T2 are the states at another.

If my friend religiously pumped up his pressure to 140 psi (=P1) in the 70 degree F (=T1) comforts of his home, and then went out to ride in a muggy 100 degree F temperature (=T2, a 43% change from his house), we can solve for the pressure in his tire, P2.

Thermodynamicists like to stick with absolute temperatures like kelvin, instead of empirical ones like degree F. To convert F to K, you add 273 to the Fahrenheit temperature. Then T1 = 343 K and T2 = 373 K.

Since kelvin is an SI unit, you can't do math with apples and oranges and so pressures would need to be in Pascals. 1 psi = 6895 Pa. Converting, P1 = 965266.02 Pa.

Following our intentions to then solve for P2,

Converting this pascal value back to psi, we get the modified pressure = 152.24 psi.

So a 43% temperature increase has just shot the pressure up by 9% ! This basic math doesn't consider the other heat additions through braking and side wall deflections.

Ofcourse, I won't tell my buddy about all this. There's some amusement in seeing how many flat tires he'll be getting in the coming days through that nasty pumping addiction.

* * *

Correction (Aug 11) : The heat wave has apparently fried a chunk of my brain too. The comments from some readers were right. The conversion factor of "273" I used to convert F to K was actually to convert C to K. Correcting this, 1 deg F = 256 K, and so T1 = 294 K and T2 = 311 K. The correct math then is :

which, as it turns out, is 8 psi over-inflated (6% increase, not 9%).

Related Articles On This Blog :

Cycling in Heat & Helmet Cooling Power (Jan 4, 2010)

Bicycle Chain Stretch Test & Results

noreply@blogger.com (Ron) — Sat, 28 May 2011 05:43:00 +0000

Do bicycle chains get stretch marks? Will smearing cocoa butter on them be a step in preventive maintenance for future? I don't know, but hold that thought for a moment.

I, like many, am a fan of chains. For bikes, they present a technology that is ubiquitous, economical, and proven to work almost seamlessly with external shifting systems. Belts are slowly staking their claim in the single speed road and mountain bike arena, however I have to be honest - show me a more simpler, self cleaning power transmission mechanism that doesn't load up shafts and bearings as much as a belt does, and I'll be sold on other ideas.

".. the less stretch, the more responsive the bike becomes.."

But in cycling, as we all know, equilibrium is rare. Everything has to get scrutinized more thoroughly than a coroner would do a murder victim, from the pimple on our skin that's disturbing laminar air flow to the secret ingredients used to make those mundane Presta valves and you know, that's what keeps our world a bit interesting (or not).

Now if you just may recall, Wipperman was getting fancy in the recent past by testing a host of chains in order to rate them according to their wear rates. You can read that blog post here which described the test protocol, the results they came out with and so on.

Recently, I was told that the company commissioned a different test on a similar selection of chains to test for elongation under load. Tom Petrie of Cantitoe Road - a chain test data center - passed along some literature that said the following :

"Wippermann recently tested a number of popular 10-speed chains for stretch under load. For a reference point, each chain’s length was measured under a nominal load of 10 kg. Then each chain was measured under 75kg and 150 kgloads, and the results recorded. Not surprisingly, chains with cut-out plates and hollow pins stretched more than those with solid plates and pins. And, the chains that stretched least were the Wippermann’s Connex 10 series with solid plates and pins!

How much a chain stretches under load affects how quickly the load is transferred to the driven cog. The less stretch, the more responsive the bike becomes. And, less stretch means less energy is lost to stretching the chain! Especially in sprint, time trial, or hill climb events, reducing these losses is critical.

Wippermann tested 31-link sections of chain. This is the average number of links under load between chain ring and cog. While the actual amount of stretch is small (from 1.10 to 2.15 mm) the differences are substantial. Among the various chains tested, the “stretchiest” stretched almost 100% more than Wippermann Connex!"

After testing, the data was cobbled up into a table to make sense of the results. They follow :


Summary of chain stretch test data

Elongation vs load plot

The document went on to make light of these :

"In addition to raw material and proprietary heat-treating processes, the shape of Wippermann Connex outer plate is largely responsible for its resistance to stretch. Note that chains featuring elaborate side-plate cut-outs and hollow pins are the “stretchiest” while chains with solid plates and solid pins stretch less. But even solid-plate solid-pin chainswith sculpted “figure 8” outer plates stretch more than Wippermann Connex. The extra-strong rectangular outer plates on Connex chains contribute significantly to their resistance to stretch."

This stretching they're talking about should be nowhere big enough to cause a yielding in the chain material. So the material attains its original shape after unloading like a spring, and the real question then becomes - how will a 100 thou inch change in chain length in the worst case scenario affects overall power transmission efficiency? Is it any more significant than the normal vibrations introduced into the chain due to tensile load changes and sprocket tooth effect? Does the stretching get better or worsen in weaker chains when the chain is misaligned/cross chained? Finally in the big scheme of things, how will cyclic stretching/unstretching react with notorious elements like salt water? Could it possibly accelerate the failure of cut-out chains in those circumstances?

What do you think? While you sip your coffee, you may also be interested in glancing at a "shifting performance" study done on chains through Wippermann, the hardly surprising conclusion of which was that there is no observable correlation between a worn chain and shifting performance compared to a new one. You just may not want to break your bank over a chain.

* * *

Aerodynamic Drag Chart For Human Powered Mobility

noreply@blogger.com (Ron) — Wed, 19 Jan 2011 02:01:00 +0000

This sort of thing might come in handy for your investigations. Thanks to Troy Rank, an engineering student at RIT and electric bike tinkerer, for showing me this. The chart lists the aerodynamic drag co-efficient and a host of other performance factors for human powered vehicles. I'm not sure of the true source of all this data but will duly give credit if I find out.

* * *

Best Tech Innovations of 2010?

noreply@blogger.com (Ron) — Sat, 08 Jan 2011 03:23:00 +0000

The Cycling News Reader Poll has pedal based powermeters topping the list of best tech innovations of 2010, among 9 other items. Pedal based power meters, like the one introduced by Metrigear, will tell you how much workload each leg applies into cycling motion. Positive tangential, negative tangential and net tangential pedal forces are the jargon in the list of features it offers the user. Its a solid physics based tool and I reckon that most of you in the general public who rides and who have a natural perception for pedaling efforts anyway wouldn't require a gizmo to tell you what you probably already knew - that the dominant leg works 5-10% harder than the other.

Some of the other items in the list were :

Pedal-based power meters, 4521 votes (26.9%)
GPS-enabled computers, 4095 (24.4%)
Disc brakes on 'cross bikes, 2065 (12.3%)
Wide-profile road wheels, 1386 (8.3%)
Belt-drive drivetrains, 1122 (6.7%)
PressFit 30 bottom brackets, 970 (5.8%)
BBright multi-fit bottom bracket standard, 960 (5.7%)
Carbon fiber mountain bike wheels, 955 (5.7%)
E-bikes, 362 (2.2%)
142x12mm rear thru-axles, 351 (2.1%)

What innovation made most sense to you ?

* * *

Matt Appleman On Carbon Fiber

noreply@blogger.com (Ron) — Wed, 27 Oct 2010 19:47:00 +0000

Appleman Bicycles in Orange County, CA is the brainchild of Matt Appleman. After an injury called an end to his 10 year long bike racing career, he decided to pour the knowledge gained through his college Composites Engineering degree and work experience into building carbon fiber bikes. Today, he builds custom carbon fiber bikes to suit the stiffness needs of a rider. The base price for a frame, fork, and headset is $3,500 and this includes a standard "three panel" paint job.

Besides bicycles, Matt has worked in the aerospace and wind energy industries. "From 150 ft, 13,000 lb wind turbine blades, to 2 lb bike frames... I've used composites to build them all!" he would tell you.

Matt is a follower of my blog and recently contacted me to express his extreme satisfaction (or dissatisfaction) with my website. After having learned his credentials, I chanced upon the opportunity to shoot him a couple of simple questions on CF without getting into an erudite discussion. His reply is as below. If you have further questions after reading it, feel free to contact Mike through his website or start a discussion here.

Me : Matt, you must be quite confident in carbon fiber's material properties for bicycle applications. I too believe in its benefits when properly applied. But when it shows its limitations, the consequences aren't so good. For the rest of us, tell us what makes a carbon fiber frame weak?

MA : Well it depends on a bunch of factors.

1) Material Properties : The inherent weakness of carbon fiber is that it is brittle. Carbon fiber composites have low elongation (typically 1-1.5%). The brittleness of carbon fiber can be seen from sudden impact forces like riding into a curb or large pot hole. These impact forces can bend the frame/fork to the point of catastrophic failure. The frame needs to be sufficiently strong to absorb impacts and transmit the force throughout the frame.

2) Design (or lack thereof) : The “layup schedule” or the number of layers and direction of carbon fiber is the most important aspect to building a strong bicycle. For structure, bicycles use unidirectional carbon fiber meaning that all of the fibers run in the same direction (an isotropic material). Woven fabrics are typically cosmetic.

Unidirectional carbon fiber is 30 times stronger in the fiber direction than perpendicular to the fibers. The angle of the fiber directly affects the strength of a frame!

There are many forces applied to a bicycle while riding it and each tube resists a unique set of forces. Each tube requires a unique diameter, number of layers, and fiber directions. The true beauty of composites is that you can pick the direction of the strength. To save weight, material only needs to be added in a select number of directions. A carbon fiber frame with tubes designed with equal strength in all directions (anisotropic) would weigh at least twice as much and be overbuilt! Unfortunately, frames often fail because of forces not considered when designing the layup schedule. There is always a balance of weight and strength.

3) Manufacturing Methods : Then there are manufacturing methods. There are a 101 ways to manufacture a carbon fiber frame, but no matter how the frame is made, air voids can be present. Air is the true enemy of composites. Air can be trapped between layers of carbon fiber during the layup process. If the air is not removed prior to the resin curing, a void will form. For reference, a void content of <3% is considered acceptable in most composite industries. The void is a stress riser that enables cracks and delaminations to propagate. Whether failure occurs depends on the size and location void.

Me : How do your bikes take care of this weakness issue?

MA : Appleman Bicycles uses high strength carbon fibers and toughened epoxy resin. The carbon fiber is pre-impregnated with the resin to provide consistent resin content and low weight.

By using a multitude of angles, the layup holds tubes together while transmitting loads and forces throughout the frame. The loads are distributed along the length of the tube as well as throughout the cross-section producing an extremely lightweight and robust structure.

During my time working in the wind energy and aerospace composite industries, I’ve witnessed and developed hundreds of cure schedules. Using my background, I designed new cure schedules specific for my process of building bicycles. By using heat and pressure, air is extracted from the laminate prior to the resin curing. After the air is removed, consolidation of the layers of carbon fiber is realized until the resin is cured.

Me : Thank you for your time!

SEE MUCH MORE RELATED READING ON THIS BLOG :

Effect of BVID On Carbon Fiber Bike Frames
Broken Steerer Tube : Composites Are Not Perfect
Aspect Ratios & The Spirit of Cycling as a Sport

Cannondale Six 13's Bi-Axial Braid Solution

How TIME Makes Carbon Fiber Reinforced Bike Parts

Nanotechnology Application In Bicycles : How Good?

Why Some Carbon Fiber Is So Cheap?

* * *

Metallurgical Failure Analysis

noreply@blogger.com (Ron) — Wed, 20 Oct 2010 20:08:00 +0000

Part failures are a common story in world of cycling - be it metal or composite parts. If you have ever experienced a metal part failure yourself that was a factor in any injury, have that part sent to someone knowledgeable in metallography.

Metals have existed for thousands of years and both their theory and their analysis have been perfected through science. Mainstream carbon composites sprang up during the 50's and 60's so understanding them is still bit of a niche field. But who hasn't bent or welded a metal part in their garage at some point in time?

Speaking of metal failures, agencies exist today that not only can analyze a specimen of a failed part blown thousands of times larger by microscopes but they can also perform chemical and impact tests on the part to determine if the composition of the metal was as per the specifications, and whether attributes related to heating - such as the thermal alteration during welding and cutting - had any part to play in the breakage.

A nice overview of these processes was provided recently by the ME Magazine. With this brief introduction, it may help you decide whether its something you want to pursue through an expert if the injury case is significant. This route may cost a good amount of money but both accuser and the accused can come to an agreement as to who was at fault in a technical and professional manner. One example of a case where metallurgic expert lent his insight to the victim of a bicycling accident was explored in one of my previous blog posts here.

* * *

Robic's Crash Scene

noreply@blogger.com (Ron) — Tue, 19 Oct 2010 03:44:00 +0000

The scene of Jure Robic's fatal crash that left him dead is below. I was a bit late to the news but boy was I shocked to hear this. One day a great champion, next day, your number is up. I wonder if Robic had the chance to spend time with all the people he cared for before he passed on.

Life's so short and precious that often I wonder about all the things you miss when you spend all your damn time and life around a dum bicycle, you know. I mean, so many other things matter more in life, doesn't it?

Please take care out there while you exercise. While we mull at the loss, here's an interview that NYTimes did with Robic back in 2006.

Braking Induced Fork Failure

noreply@blogger.com (Ron) — Sat, 02 Oct 2010 04:22:00 +0000

Here's another image of one of those braking induced fork failures that crop up from time to time. This was sent to me by a reader. The entire story of how the accident occured is mentioned on this blog.

Because of the lack of telescopic front suspensions like those nice mountain bikes have, rigid forks take the full brunt of a combination of two forces. One is the braking force that acts longitudinally backward to direction of motion but this has a component along the axis of the fork as well. The other is the force due to braking load transfer towards the front of the bike. This force acts inline with the fork axis. In essence, the two forces add together. I'm fairly certain that the quantity of this directed force along the fork is strongly dependent on the wheelbase of the bike and the rake angle of the fork. Lower wheelbases equate to more load transfer. Higher rake angles must also promote higher fork forces.

Undersized, thin walled tubes, such as forks, do not act kindly to hard braking forces. An example of this kind of buckling along with its physics was provided sometime back on my blog.

Thanks for reading. Have an enjoyable weekend and exercise safely.

* * *

String Transmission

noreply@blogger.com (Ron) — Wed, 22 Sep 2010 14:37:00 +0000

It looks like one of those linear drive systems have shown their face again. It was in 1897 that a patent, granted to a teen Swedish inventor Birgin Ljungström, showed the world a linear drive bicycle where the pedals moves in linear, reciprocating fashion. The project was sponsored by dynamite inventor Alfred Nobel. Ofcourse, numerous other linear drive systems for bicycles have been invented since then.

Recently shown on the Internet by a Hungarian bicycle design team was a linear drive bicycle. The system we're looking does involve circular pedal motion but the symmetric cam mechanism ensures that a string or rope constantly winds and unwinds on both sides of the bike, transmitting torque through the freewheel of the rear hub. Some videos are attached below to show the design and operation of the drive.

Discuss the possibilities and negative aspects offered by a symmetric drive system such as number of extra moving parts, ease or difficulty of adjustment, gear ratio variability, safety etc.

The 'Age Group' Business

noreply@blogger.com (Ron) — Sun, 19 Sep 2010 16:10:00 +0000

"I raced at this [insert name here] TT. Shaved 3 seconds off my time & seventh in my age group!"

"Why that's an awesome result, [insert name of other person here]! ....Just curious, how many people raced in your age group?"

"...Seven."

Do you suck as a bike rider? Want to sugar coat the real results?

Pull the age group card! There's an age group result for everyone!

Use today! Hurry..before another sucker beats you to it!

* * *

A Boy and a Bicycle

noreply@blogger.com (Ron) — Fri, 17 Sep 2010 04:54:00 +0000

This was published recently in the NYT Op-Ed section written by none other than Nicholas Kristof. He's a 2 time Pulitzer Prize winning American journalist, whose columns I like to read from time to time because of his tremendously insightful accounts of poverty, social and human rights issues in some of the poorest places in Africa.

This latest column is about the efforts of World Bicycle Relief in fulfilling the needs for a practical mode of transportation for poor kids in Zimbabwe, many of whom have to walk several miles to get to school. Some of the background operations of the organization has been broken down for us and some light is shed on the nature of challenges they face in successfully running a bicycle equip program in these poor villages. Come discuss the article after you have read it. Have you been involved in any such programs here or abroad?

"Early this year I wrote a column from Zimbabwe that focused on five orphans who moved in together and survive alone in a hut.

The eldest, Abel, a scrawny and malnourished 17-year-old, would rise at 4 o’clock each morning and set off barefoot on a three-hour hike to high school. At nightfall, Abel would return to function as surrogate father: cajoling the younger orphans to finish their homework by firelight, comforting them when sick and spanking them when naughty.

When I asked Abel what he dreamed of, he said “a bicycle” — so that he could cut the six hours he spent walking to and from school and, thus, take better care of the younger orphans. Last week, Abel got his wish. A Chicago-based aid organization, World Bicycle Relief, distributed 200 bicycles to students in Abel’s area who need them to get to school. One went to Abel.

The initiative is a pilot. If it succeeds and finds financing, tens of thousands of other children in Zimbabwe could also get bicycles to help them attend school.

“I’m happy,” Abel told me shyly — his voice beaming through the phone line — when I spoke to him after he got his hands on his bicycle.

Before, he said, he wasn’t sure that he would pass high school graduation exams because he had no time to study. Now he is confident that he will pass.

The bicycle project is the brainchild of a Chicago businessman, Frederick K.W. Day, who read about Abel and decided to make him and his classmates a test of a large-scale bicycles-for-education program in Zimbabwe.

Mr. Day is a senior executive of the SRAM Corporation, the largest bicycle parts company in the United States. He formed World Bicycle Relief in 2005 in the belief that bicycles could help provide cheap transportation for students and health workers in poor countries.

At first, his plan was to ship used bicycles from the United States, but after visits to the field he decided that they would break down. “When we got out there, it was clear that no bike made in the U.S. would survive in that environment,” he said.

After consulting with local people and looking at the spare parts available in remote areas, Mr. Day’s engineering staff designed a 55-pound one-speed bicycle that needed little pampering. One notorious problem with aid groups is that they introduce new technologies that can’t always be sustained; the developing world is full of expensive wells that don’t work because the pumps have broken and there is no one to repair them.

So World Bicycle Relief trains one mechanic — equipped with basic spare parts and tools — for every 50 bicycles distributed, thus nurturing small businesses as well. Abel was one of those trained as a mechanic this time.

In the world of aid, nothing goes quite as planned, and it’s far too early to know whether this program will succeed. World Bicycle Relief tried to get around potential problems by spending months recruiting village elders to oversee the program (it helps that the elders receive bicycles, which they get to keep after two years if they provide solid oversight). Elders will ensure that fathers and older brothers do not confiscate bicycles from girls on the grounds that females are too insignificant to merit something so valuable.

Parents sometimes try to save daughters the risk of walking several hours each way to school by lodging them in town. But the result is sometimes sexual extortion; if a girl wishes to continue her education by staying in cheap lodgings, the price is repeated rape. With bicycles, those girls will now be able to stay at home.

World Bicycle Relief has given out more than 70,000 bicycles so far, nearly 70 percent to women and girls. It expects to hand out 20,000 bicycles this year. And if all goes well, Abel may be the first of tens of thousands of Zimbabwean students to get a bike.

So, for Abel, this is something of a fairy-tale ending. But one of my challenges as a journalist is that many donors want to help any specific individual I write about, while few want to support countless others in the same position.

One obstacle is donor fatigue and weariness with African corruption and repeated aid failures. Those are legitimate concerns. But this column isn’t just a story about a boy and a bike. Rather, it’s an example of an aid intervention that puts a system in place, one that is sustainable and has local buy-in, in hopes of promoting education, jobs and a virtuous cycle out of poverty. It’s a reminder that there are ways to help people help themselves, and that problems can have solutions — but we need to multiply them. Just ask Abel."

2010 Highlander Highathlon

noreply@blogger.com (Ron) — Wed, 15 Sep 2010 14:35:00 +0000

Bike Ride : 130 miles
10,000 Ft of climbing
Ride Time : 10 hours
Day : Saturday, 11 Sept
Location : Finger Lakes, NY

Run Distance : Full Marathon
Time : 4:20 hours
Day : Sunday, 12 Sept
Location : Rochester NY

I have been away for more than a week or so from this blog mainly because of my preparation for this event, what they call a Highathlon. I did it!! Now I'm recovering from some kind of over-training symptom but I'm okay. The above video is a satellite flyby of my weekend adventure, easily one of the toughest things I ever had to do in life so far.

The bike ride is one of the most challenging in the country and few people have even heard about it. This year, the folks with the Highlander Cycle Tour team aptly called the marquee ride "Death Before Dismount", a double metric featuring over 10,000 feet of total climbing. The name is bit striking - it was perhaps telling the riders that if they were crazy enough to even think of doing something like this, they'd rather jump down a cliff and expire themselves than shamefully dismount the bike while attempting to traverse the sick inclines of the route. Was it in any fashion supposed to carry a reminder to ideals of the medieval Japanese Samurai? I don't know...

I have already mentioned last year why it manages to match (or even exceed) the difficulty of the Triple Bypass ride in Colorado. The ride features short, nasty, steep hills one after the other, all of them mostly in the range of 8-13% grade, like one giant rolling route on asphalt enhancing steroids. You are challenged constantly in finding a suitable gear and a rhythm to climb, unlike long climbs that take 20 or more minutes to complete where you can settle down at some point into a zone.

But on a full plate of luscious pain, you are served a side of some of the most beautiful views of the Finger Lakes area that you may ever see as you climb over 15 climbs in the region and visit both Canandaigua Lake and the oddly shaped Keuka Lake.

For the people who didn't think this ride was enough challenge, 10 or so folks including me ran the full marathon the very next day in Rochester. This was what they call the Highathlon.

Last year during the Highlander Century, I had painful seizures in my lower back and something slapped me in the face making me realize why its so important to build core strength to do an extreme event like this. This year, my core had no problem but I was suffering from cramps on the inside of the thighs during the last 30 miles. Some of the initial climbs were on newly chip-sealed roads so it was near to impossible to stand and pedal because of loss of traction.

At mile 90, the organizers wonderfully planted two asphalt walls before you - the initial sections of Skyline Rd followed by the infamous Yoder Hill - a climb that stands so naked and steep before you that it plays games with your mind. Most people who attempted the ride said this was the climb that took them out. Both roads are in the range of 10-12% average grade and its not unlikely to see a 18% or a 20% step here and there.

As the route unraveled itself over that day, we were constantly asking when this ordeal would be over but the roads near to the end at mile 110 were not easy either. Cold and tired, we found ourselves snailing across the last portions of 6 and 7% grades until we were back in Bristol Mountain after 10+ hours of ride time for a hearty meal and a chance to share an adventure with others who were just as tired as you were.

But in an event like this, its always the marathon that roundhouse kicks you straight in the face.

I woke up the next morning with 5-6 hours of sleep and choke full of Adrenaline with a capital A and started out the first 10 miles with 800 other people at a pace that I couldn't sustain for the complete run. 7:50 mile pace crashed down to 9 or 10 mile pace after mile 13 and all I wanted to do after then was just finish. The route was by no means flat and there were inclines along the historic East Ave as we passed sights like George Eastman House. Then there was a 2 or 3 mile section of Erie Canal trailway that featured nothing but gravel and the wretched stones didn't do good to my feet.

I guess pushing yourself like this doesn't come without some "gifts". :)

Hence, I ran my first marathon with painful blisters and a searing pain in both toes of my feet. Later, when I sprinted past the line at mile 26.2 in downtown Rochester at the Frontier Stadium, and crashed into the grass near me, I inspected my feet to find two nice black toenails on both feet. I limped over and got minimal medical attention just to make sure I wasn't going to lose my damn toes!

It was all going to be okay, said a medical staff. "Don't apply much pressure to the feet for a week, a new nail with grow and the old one will fall off." Me and a buddy who did the marathon together walked 1 mile back to his apartment with some shining medals around our necks. What a weekend!

Will I do it next year? If I have the time, you bet.

* * *

Safety Moment : Speed Wobble and Jaw Fracture

noreply@blogger.com (Ron) — Mon, 06 Sep 2010 05:35:00 +0000

Will Cheng is an electrical engineering Ph.D. student at Stony Brook University here in NY. In their free time, he and his sister ride their bikes with a group of retiree friends in Long Island.

Early in August, Will met with a nasty bike accident during a pace-lined group ride that left him with a fractured jaw. He was rushed to the ER where doctors had to perform an 8 hour surgery on him to patch up the severe injury. Some who witnessed the accident had advised him to contact an attorney. Meanwhile, the medical and dental costs for the operation had been tallying up and taking uncomfortable proportions.

He contacted an attorney who recommended him to get in touch with a mechanical engineer who could look into the background of his cycling equipment.

At the time of the accident, Will happened to be riding a 2006 Orbea with Mavic Cosmos wheels fitted with Schwalbe Blizzard tires. I was informed by his sister that Mavic no longer makes the wheelset. Will's own account of the accident later to her was as follows :

"I was on Clay Pitts road [in East Northport] and I moved up to second wheel in the pace line at the light on Elwood road. After pedaling for a while [at 20mph], I noticed that I was a little to the left of the shoulder. I corrected by moving the wheel a hair to the right so I was heading towards the white line slowly. I then turned the wheel back to the left to straighten out.

That's when I felt no resistance or feedback from the wheel and handle bars. I assumed that I went over a dip in the road and recall crying "WHOA" and thinking that the leader should have warned us. This was followed by a gross turn of the wheel to the left. I panicked, simultaneously turning the wheel straight ahead and clipping out my left foot.

I felt the bike wobble a little, after which it diminished and stopped. At that point I thought I was OK but a split second later I felt something was wrong. Before I could do anything, I was falling. I do remember that when the wobble disappeared, I was staring at my handle bars and saw that it was straight without signs of the wobble. I thought I was safe and I looked back up at the road. I don't really remember much, but I think I still had my hands on the handle bar right when I hit the ground with my chin. I didn't have a death grip on the bars but my grip was firm and my hands were always on the top of the bars."

As far as I have looked into the wheelset through some internet searching, I haven't found any design related issues and its performance limiter really depends upon who built it. In more cases than not, a crash is what causes a wheel failure. At other times, it is fatigue failure or some very high external load not expected in normal usage of a bicycle that causes spokes to pull through. Wheel experts say something in excess of 2000 N of force is required to pull a spoke out of the rim.

From the attached pictures (see below, and more here), it seems that about 5-6 of the straight pull spokes in total had pulled out and that more spokes pulled out on nut side of the front wheel skewer than on the lever side. This corresponds with weakening and rupture of the wheel rim on the left side, when viewed from the front. Also take note that the rupture occurred right underneath a sticker on the rim so its hard to tell whether there was a hidden crack formation well before the accident.

From the description of the actions of the rider before the accident, I don't see anything particularly out of the ordinary. Steering motions such as this is absolutely normal and is to be expected. I perform more wilder maneuvers on my bike path in order to avoid sharp twigs and bumps.

What may be significant though, is the faint evidence of a speed wobble before the crash. Could a rapid left-right steering correction at 20 mph together with a sketchy road surface amplify an unwanted oscillation? Check out the image of the site of the accident.

Moreover, what gave away first - the spokes or the rim? Another bit of interesting testimony is the loss of "feedback" just before the crash, which almost wants me to question whether Will had remembered tightening his skewer that day.

Unfortunately, these questions are really hard to answer through images. I would check the tension on the spokes with a tensionometer, consult with a metallurgist who would be able to analyze the sample of broken aluminum rim (Stony Brook should have a professor who may help) and try as much as possible to take a similar wheel with the same tire, attach it to the same bike and perform some maneuvers at the speed in question.

Here's wishing Will the best of luck in recovery. Meanwhile, if any of you have had similar experiences, do share some of your thoughts.

* * *

Electric Bike Issue One

noreply@blogger.com (Ron) — Mon, 30 Aug 2010 04:58:00 +0000

I discovered through velovision.co.uk that the first issue of the "Electric Bike" magazine is out and ready for viewing online. The publication goes a bit indepth into e-bikes for starters, what they comprise of, the models available in the market and supplier locations. Enjoy the read.

Open publication - Free publishing - More pedelec

Tour of the Highlands : Part 2

noreply@blogger.com (Ron) — Sun, 29 Aug 2010 19:05:00 +0000

140 Miles
8000 Ft Climbing
10 hours saddle time

In two weeks time is yet another edition of one of the toughest rides in the country - the "Highlander Death Before Dismount" Double Metric. 125 miles long in the beautiful Finger Lakes region, with over 10,000 feet of climbing in 16 major climbs, it will surely challenge any rider.

Preparation and judgment are keys to riding an extreme event like this. My own preparation has so far been limited to perhaps half the roads in DB4D, on the western side of the map. Following is a look at some of the roads I had managed to survey yesterday. Let this be a sequel to my exploration last year of the same area.

It was a difficult day on the bike - all alone, with temperatures in its 90's. But the sunlit landscapes I passed on the bike managed to neutralize the heat. Overall, it turned out to be an extremely pleasant experience for both sight and smell and sounds. One of the highlights of the day was that I managed to talk to a young Amish country guy, whom I asked for directions after I overshot one of the roads I was required to take by 5 miles. He had the most pleasant smile on his face as he stacked stock for his animals into a tractor. He also carried this peculiar accent, something almost out of this world. It was like he came straight out of these classic movies you see...

Enjoy these pics, all of them taken from the bike - an artform I call ciclofotografics! Do come ride in the Finger Lakes area! Its a bit different, I can tell you that much.

Route 96

High Street

Town of Victor, NY

Route 444 to village of Bloomsfield

Route 64 to Bristol Springs

Montanye Road

Descent on Deuel Road to western side of Lake Canandaigua, fourth largest of the Finger Lakes

Seneca Point Road to Bopple Hill

Bopple Hill Road - 1 mile at 11% average gradient (will be chip-sealed on Monday 30th August)

The familiar cemetery greets you at the peak

View to the eastern side of the Lake

Bills Road to Stid Hill , 1 mile at 13.4% grade

Summit of Stid Hill in Ontario NY at 2100 feet

West Gannett Hill Road - 1.35 miles at 11% grade

Clement Road

Gulick Road

Highlander Staff member Ken lays down the road signs for the event in 2 weeks. He has traveled many places in the world and was an interesting man to talk to! He offered me a bottle of gatorade or something like that from his car and wish me a good journey.

Eelpot Road

Strong Hill to Blodgett Road

Mattoon Road, after Route 53

An Amish lady is busy with her work at the farm

Descent into the rural town of Prattsburgh, NY

This ends the Highlander route. I catch a diversion - Italy Hill Road heading north.

I pass the towns of Italy and Rushville NY

Descent along Co. Rd 1 onto the eastern side of Lake Canandaigua

This is definitely a first, having explored both the eastern and western sides of the Lake

Leaving the town of Canandaigua

Homebound on the 332

Homebound on the local bike path in Rochester. It is dusk here. This ends 10 hours of cycling.

* * *

Modern Bicycles and Cycling Speeds : Any Measurable Relation?

noreply@blogger.com (Ron) — Sat, 21 Aug 2010 03:09:00 +0000

Its not about the bike. Or is it?

Without a shadow of doubt, most of us will say that today's Grand Tours are faster than those of the past. True. For instance, since its inception in 1903 to the 1990's, the Tour de France had seen its winner's average speed increase some 50-55% as this site will show.

But here's the big question - how much of that speed increase came from bicycle improvements alone? If you don't factor in the contributions from all other things- temperature, course, race tactics, improved training methods, nutrition and doping - what role does bicycle technology alone have to play in higher speeds? Is it significant to be appreciated?

This most entertaining problem is one that maybe analyzed with a technique called multiple regression. This method, a staple in any statistician's arsenal of tools, allows one to estimate the effects of many factors on a single dependent variable, in our case - cycling performance.

For starters, there are a number of independent variables that factor into a favorable cycling performance. I have shown these factors diagrammatically below.

In my opinion, these independent or explanatory variables can be broadly termed into 4 categories :

1. Human Performance Related - Physiology, training, nutrition, medicine and doping
2. Technology Related - Bicycles, fancy apparel etc. We'll disregard other things and consider just bicycles.
3. Race Specific - Course, weather, tactics employed, rules, etc.
4. Random Events (Noise) - Example - a freak crash 2 km from the finish line that injured many riders, a neutralized stage due to the death of an athlete, any day to day variation that cannot be predicted but is present.

In 100 years of cycling history, innovations have come and gone. Some have stuck through to Grand Tour racing, the list of which is mandated by the final word of the UCI.

To consider the effect of just bicycle technology alone on cycling speeds, a multiple regression analysis has to be performed. You would require lots of data for many years and a handy computer to make some meaning out of it. Unless someone gives me serious money, I won't be diving into such an endeavor.

But recently, Ph.D's Jan Heine and Mark Vande Kamp who write for the magazine Bicycle Quarterly sought to answer this question in their article titled "Are Modern Bicycles Faster? An Analysis of Tour de France Speed". To me, the article appeared to be a logical investigation of why speeds increased in the Tour and whether they could be explained by the latest racing bikes.

The article had ignited controversy in cycling circles about its apparently "flawed" analysis. I think it will be to everyone's benefit if the strategy of the article's investigations are clarified first and foremost. We'll then explore its conclusions.

Here's the strategy behind the article's investigation :

1. Fundamental assumption : The fundamental assumption that the authors imply, but which is not stated explicitly in the article, is that all modern bicycles and related technology are introduced into the market to strictly increase cycling speeds. With this assumption, they proceed to quantify how much that speed increase is.

2. Eliminate day to day performance variations : They selected the Tour de France as the main race of interest with this notion that multiple stages and over 150 riders will eliminate the influence of day-to-day variations in fitness, weather and other factors on individual performance.

3. Eliminate course specific variations : With the view that courses change "somewhat" in the Tour de France, they selected the Milan-San Remo as a supplement in the analysis as the race has been run on the same course for over a 100 years without change. The race's difficulty has also been consistent since smooth speed curves have been displayed for over a century.

4. Separate human performance improvements from bicycling technology improvements : This one is tricky so pay attention. The authors wanted another race as a control to compare cycling with. They thought of a race from another branch of endurance sports that had little to do with technology or inconsistent conditions and where performance was mostly limited by the "human factor".

They selected medium distance running, specifically the 5 and 10 km running race from all events worldwide and studied trends in running speeds. The logic? If bicycles have truly become faster, the trend line for cycling speeds in the Tour would deviate from that of human speeds in running by showing step increases. If bicycles have not become faster, the trend lines should closely match each other due to the "human factor" common to both endurance sports.

5. Regression Analysis : Using the data of speeds, a regression analysis was performed on the Tour de France and running speeds for the last 100 years. The "athletic performance" regression lines would show the long term speed trends for both races. This was made into a "Chart 1". "Chart 2" was also made where the authors smoothed TdF and 10 Km running speeds for many years by taking a 5-year running average. These curves were compared to each other and to the long term "athletic performance" regression line in Chart 1.

Summary Of Results :

1. Co-relation between actual TdF speeds and speeds predicted by the runner's trend line was 0.94. Strong.

2. Co-relation between actual running speeds and the long term running speed trend line was 0.95. Also strong.

3. 88% of increases in TdF speeds over the last 100 years can be explained by improved athletic performance.

4. For both running and cycling, there appears to be an unexplained 9-12% that are simply random occurrences seen when athletes compete.

5. The regression curve (or line fit) for TdF speeds have a shallower slope than that of running indicating that cycling speeds increased at a slower rate. The authors propose that this is due to wind resistance factor in cycling as power demand increases by the cube of velocity. But the non-linearity of aerodynamic resistance is not much, it is instead minimized in the Tour de France and spread over a large group of riders.

6. Over the last 20 years, TdF speed increase trends parallel that of runners' speeds. Technology has had minor roles to play in these achievements according to the logic in the analyses (no step increases were observed).

7. There were steeper speed increases in the TdF in between 1926-1940 than running speeds during that time. The early 1920's saw periods of low performance and the authors propose that World War I had depleted the pool of cycling champions taking part.

The late 1920's, however, showed a marked speed increase was not observed in the Milan San Remo which got the authors to conclude that something particular to the TdF caused these increases. They propose the radical shortening of stage distances as a possible reason.

There were pronounced speed increases in the 1930's that corresponded well with the significant, revolutionary and long term changes introduced on racing bikes such as lightweight steel frames with thinwall tubing. The authors state that of all advances, lightweight steel frames had the most pronounced effect on Tour speeds. These speed increases were also observed in the Milan San Remo in the 30's as well, indicating that this was a sport-wide phenomena.

8. Since 1947, speed increases in cycling, relative to runner's speeds, came during times when cycling technology did not even change. The late 1950's saw a jump in cycling speeds but nothing significant was invented or innovated in bicycles during that time, since the introduction of Compagnolo's rear derailleur in 1951. Since speed increase came at a time when technology was stagnant, the logical conclusion is that speed increase cannot be explained by technology. The authors state that other reasons, like the paving of roads, may have been primarily responsible.

9. In the early 1980's, TdF speeds increased between 1981-1982 without a rational reason and then dipped down without an explainable reason as well. Between 1985-1990, time trial bikes, such as those used by Greg Lemond in his 1989 Time Trial did increase stage speeds but the time trial stages were too short to influence overall speed of the entire Tour. Moreover, the bikes used in mass-start races "evolved little" during this period, wrote the authors.

10. From 1999-2009, lots of things in bicycles evolved - from index shifting, to rear cassettes, increased gearing, aerodynamic wheels and ceramic bearings. Sure, the speeds of the Tour de France saw an almost linear increase as well. But what the authors found was that the long term trend of running speeds tracked this increase in cycling speeds very closely indicating that almost all these improvements can be tracked to physiological factors common to both running and cycling.

Since 2005, speeds started to drop below the predicted trends, possibly indicating that strict doping controls are responsible for the lower speeds. Speeds decreased 3.5% from their peak, while running speeds decreased only 1.8%. This shows that something not common to both sports have influenced the speeds in cycling.

By now, you must be tired with all this information overload. So let's take the justifications provided by the authors for speed fluctuations and plot it on a chart for the last 100 years. I did it below for you :

Conclusions :

The authors wrote that there is no evidence that advances in cycling technology since WWII led to faster racing speeds. There is no systematic co-relation between the two. Some speed increases came during times when athletic performance as a whole were increasing. Others came at times when bicycle technology and innovation were stagnant. The only period where bicycling technology led to a pronounced speed increase was during the 1930's with the introduction of lightweight steel frames. Bottom-line of this whole affair is as follows, quoted from the article :

"It is tempting to look over the Tour de France speed curve and pick [technology] factors that appear to have caused increases or decreases in speeds. [...] However, when taken in the context of all the data, these specific examples don't add up to a compelling case that bicycle technology increased Tour de France speeds. Neither of them stand up to close scrutiny. [...] Across the whole timeframe of the last 100 years, even radical changes like the introduction of the derailleurs did not alter the trend of Tour de France speeds. Clearly, the larger pattern suggests that bicycle technology has had little, if any, effect on racing speeds, especially in recent decades."

Critique & Suggestions :

1. Choice of control : Why was medium distance running chosen as a control and not ...say, the marathon? I don't know. The authors don't provide an explanation for this deliberation, although they suggest that the medium distance races do not see much "influence of technology". So does the marathon see influence of technology then? I don't know. You would think not. Long distance running, to me, is the purest form of endurance sports. It would be interesting to see if marathon running speeds closely followed all the trends of cycling speeds for the past 100 years.

2. Choice of race : One will agree that are simply too many variables in the Tour de France to make a valid relation between one aspect, such as cycling technology, and another aspect, cycling speeds. Why not extend the research to a solo performance such as the hour record where variability is reduced even further? Or a time trial? Or a sprint? In a past post, I revealed details of a study that found that between 1980 and 1990 before UCI regulations came about, 60% of cycling hour records in the discipline were solely due to engineering. The authors may want to catch up with that.

3. What to investigate : The authors start off the article by asking the question - how much faster are the lastest racing bikes compared to classic machines? But it seems that throughout the article, they tend to look at small innovations across years such as the rear derailleur, or increased gearing, or thin walled tubing to see if they made an effect on the "overall" speeds of each year's Tour. How could does a tiny component translate to anything appreciable in the overall speeds across successive years? Rear derailleurs or improved front brakes alone don't make any appreciable change to Tour de France speeds across successive years.

4. Details of each stage : The exact details of each stage were not investigated by the authors. It would be interesting to see how many flat stages and how many mountain stages each Tour so far consisted of and how gravity would play a role in changing outcomes. Data may be tricky to find. Now keep in mind that we do have data for the speeds, distances, number of entrants and number of finishers in each of the Tours. Perhaps blending all this information into one graph for different eras of cycling may lend some insight.

For illustration, lets take the Hinault Era (1978-1985). I plotted speed (kph), % of entrants who finished the race, and number of stages with respect to the years and the distances involved. Check this out :

You may be able to come to some kind of understanding about what was going on in those 7 years. For instance, during 1980-1982, speeds increased drastically. It is also interesting to see that between 1980-1981, the number of participants who finished the race had also risen and the distance in Km of the race had fallen, although the number of stages were increased from 22 to 24. It would be interesting to superimpose the percentage of km in uphill roads and downhill roads on this graph for those years. It would also be interesting to see how the "Badger's" temperamental tactics and pace control influenced the speeds in those years.

5. Successive yearly investigations vs leaping : Based on the initial question posed, it would be more meaningful to take a vintage racing bike and a modern racing bike and compare the two. Hypothetically, a 1903 racer traveling across a period of 100 years into the future to ride the Tour de France on a 2010 race bike with a lighter frame and aerodynamic wheels should be faster. Similarly, a group of 1903 racers climbing a 2 hour long Alpine climb on 40 pound steel bikes would be slower than the same group of racers riding on flyweight machines of similar sizes in similar terrain. It is basic physics.

Investigating this issue year by year, where all riders would have access to the same bikes and the same technology won't show you clearly how cycling technology is improving overall Tour speeds, if they do at all. Besides, some modern equipment and technical wear don't always serve to increase speed solely. Some of them have intangible benefits as comfort and so on. That is an advantage when you stay seated in the saddle for 90 hours of racing.

Overall, I don't think this is as bad of a study as many people think. Besides, it was published in a popular magazine to open up a forum for discussion. It is not a rigorous scientific white paper.

I do agree with one thing that studies like this discover time and time again - that majority of racing performance is related to the human body.

Racing is never a level playing field, no matter what race it is or how much you want to complain - be it the Berlin Marathon, or the Tour de France, the 24 Hours of Le Mans or the Baja 1000. There's always those few individuals genetically gifted or blessed with the finances and talent needed to win.

Then there are those who cheat to win. They may have the talent, but they want to boost it with some extra energy from extraneous sources, illegal by all rules.

Kamp's and Heine's study corresponds with several people's observations that cycling speeds have been coming down since 2005 due to doping regulations. In July during Tour time, I had done my own analysis of this Stage 17 power to weight ratios and my approximate figure of 6 W/kg agreed with other people's observations, among them the Science of Sport bloggers (see their article).

In the end, we may never know exactly what portion of those early TdF speed increases were "fabricated" through cheating. How much came from Amphetamine use, or alcohol, or narcotics, steroids, growth hormones, EPO and blood transfusions or using mechanical devices? Food for thought?

What do you think? Come discuss this article and its implications!

* * *

Cycling Shorts : August 17, 2010

noreply@blogger.com (Ron) — Tue, 17 Aug 2010 13:55:00 +0000

1. Prince McQuaid keeps room open for donations : According to reports, the immaculate cycling chief McQuaid has said that in the future, the UCI "may deal differently" with a donation like Armstrong's. But he insisted that it depends heavily on donations from all riders and teams to support its annual $6.4 million anti-doping budget. Wow! This must happen only in cycling. Please audit this organization as soon as possible. The sooner the better.

2. The subject of Armstrong surely divides opinions. The latest Facebook groups that have come up to gather support for each of their causes are "Petition To Drop The Federal Investigation of Lance Armstrong" and "Petition To Investigate Lance Armstrong For Fraud". The bottom-line logic of the pages are something like this. One has it that investigating Lance Armstrong is a complete and utter waste of taxpayer money and that he should be let "free" because of the things he has done for the cancer initiative. The other writes that using taxpayer money to investigate fraud on such a massive scale is a non-issue, and interestingly, is also in support of the research on cancer so that definitive links can be established between drug abuse and cancer. Both sound equally reasonable.

3. Jeff Novitzky fanpage : Meanwhile, what appears to be a psuedo Jeff Novitzky is fast becoming a celebrity on Facebook as well. He must be the modern day manifestation of all our childhood fantasies about steadfast, no-tables-unturned, mission oriented crime busting.

4. Is the Cobra trying his venom already? This is the second time Riccardo Ricco has fooled us. Here, it was Quickstep. A few days later, it is now a Dutch team. I don't trust him. I think he's still lying and will surely ride for the Reptile Rescue Committee of Italy instead. Hey, that's just me.

5. Are modern bikes faster? This was the interesting question posed by an article published in the summer edition of the Bicycle Quarterly where an analysis of the impact of lightweight bicycles was done. According to those who read it, the authors of the article looked at bicycle improvements on racing speeds over the last 100 years. They then compared the trend-line of speed increases in the TdF to medium distance running and arrived at the conclusion that bicycle improvements such as lightweight tubing and derailleurs really didn't have that much of an impact. They also make a few comments on the impact of doping on the two sports. I haven't read it but it must be some food for thought. Besides, the editors of the magazine seem to be avid cyclists with PhD's. If someone is nice enough to share this article with me, we can discuss it.

6. Side Mounted Pedals : Recently, I was shown the side mounted pedals by inventor Steve Lubanski. While his pedals have been around for quite some time, it is only recently that I noticed it. It seems to me that you can get your seatpost lower with the pedals, thus lowering your center of gravity. It also appears to me that your crank length will closely match your true crank length since there is no vector addition due to the stack height offset. But will 2-3 cm of pedal stack height reduction really make that much of a big difference? Physiologically, validation could be best done with a bio-mechanical as well as power output and oxygen cost study. I might write more about this later. The subject has interested me.

What do you think? Got anything to share? Write in!

Useful Cycling Devices

noreply@blogger.com (Ron) — Mon, 16 Aug 2010 06:13:00 +0000

As a touring cyclist, I am well acquainted with the fact that almost all cycling advice and almost all cycling equipment is made for the high-tech, high-speed, ultra-light, streamlined cyclist. We hear of the need for cyclometers, cadence monitors, altimeters, heart-rate monitors, and combination devices that can record and print back the entire trip. But did you know that touring cyclists have their own high-tech devices? Here are some of them:

The Realometer was invented by H. Thoreau (a former pencil manufacturer) and is designed to measure the truth behind appearances. In 1968, Postman and Weingartner called this "an instant, built-in, crap detector." This device is useful for measuring the truths of statements such as the following: "This back road here's too dangerous, but that main road over there is very safe." "My dog snarls, but he don't bite." "It's downhill the rest of the way." "Turn left at the second light, go several blocks, and turn right. You can't miss it."

Just as you can conveniently record your speed, cadence, altitude, and resting, pacing, climbing, and maximum heart rates, now, with the Meteorological Max Kit, you can record all the meteorological data at the same time, maximum and minimum temperature, precipitation, barometric pressure, and solar intensity. The company will even sell a program to allow you to statistically correlate all these events. Does a hot sun really slow you down or speed you up?

The Sunrise, Sunset, and Rainbow Recorder was designed to measure and record daylight phenomena the cadence-conscious cyclist can now without guilt ignore. The same company produces a Moonbeam, Starlight, and Falling-Star Recorder that measures and records evening phenomena the same way. Soon to be marketed is a wild animal counter for the Nature lover as well. This last device will keep up with the individual species for you, so you don't have to bother. It even has a roadkill switch allowing you the option of counting or not counting these animals (some people consider counting roadkill to be cheating; with others, that's all they've got).

The Automatic Panorama Device detects any scenes that could be described as beautiful, scenic, or panoramic. This device has three switchable options: Alarm sets off a buzzer, so you can lift your eyes off the cyclometer and glance around; Record does not disturb you, but makes a record of the occurrence for a later trip report; Camera will work with an attached wide-angle camera or video recorder to capture the scene without disturbing your concentration.

The Blood, Guts, and Awful Flames Detector will set off a loud buzzer whenever you near a fatal traffic wreck, burning gasoline truck, or spilled train tank car. This was the one device I found to be unsatisfactory. I found I could pass two or three cadavers before it would finally go off. Definitely, the device needs to work before you get to the accident.

The Instant Poetic Inspiration Device is not as instant as the makers claim. Before it will produce a single poem, you have to hook it up to a PC or a Mac, and you must have a 233 processor and 32 megabytes of RAM. Nonetheless, the device did produce poetry that was judged as good and as understandable as anyone else's and did so without requiring one moment's reflection. [Note: the software in this device has recently been updated to make it compatable with Windows 98 and Windows 2000; it now requires a Pentium III and 128 megabytes of RAM and works nearly as well as it did before; a Macintosh version is no longer available.]

The final device is the Prevaricator. Certainly, no device was ever needed more by a cyclist. This device helps you expand your mind set, so you are equal to cyclists who are older and more experienced than you. If one says, "I have ridden to the top of Mt. Evans (14,100 ft.) in the summer," you can reply, "Well, I have ridden to the top of Mt. McKinley (20,300 ft.) in the winter," and what is he going to say to top that?

- Written by Ken Kifer , who tragically passed away on September 14 2003 in a bicycling accident

ADDITIONAL HUMOR

The Cyclist's Apocrypha
Tour of the Mountains Of The Moon

Crank Brothers Candy C Pedal Failure : 2

noreply@blogger.com (Ron) — Tue, 10 Aug 2010 06:23:00 +0000

Those Chinese made Crank Brothers Candy C pedals, whose flaws we discussed in an earlier post, has obtained another victim. The pedal failed in the same area again. A reader, who describes himself as a relatively non-litigious person, emailed me his story with pics of his injuries along with the broken pedal spindle. He describes this as a serious design flaw and wrote that had he crashed while going downhill at speed instead of the top of the hill he was riding on, he may not have lived to tell the tale.

Some good people had noticed his crash and rushed to get him to a hospital. There, he would find out that he had broken his right clavicle in two places, not to mention extensive bruises and abrasions. "It hurts like hell, inspite of Vicadin", he wrote. The healing process takes 8 weeks, or 2 months. How would you feel if your summer was ruined like this? We do hope him a quick recovery.

Fatigue is the biggest limiter of products whose design goal is to take cyclic loads and is often the prime reason for failure. Overlooking the design or manufacture of such items to combat accumulated fatigue leads to reduction of its life prematurely, that may result in serious injury or death. A rough back of the envelope calculation of mean and alternating stresses in a pedal spindle was done by me in the previous post for perspective.

Simply relying on safety factors alone does not take care of this important issue. The synergistic effects of product design geometry, heat treatment, loads imposed, environment, residual stress and time can all reduce the lifetime of a product. It is common practice to see companies show off their computer skills with exquisitely colorful FEA. This is not the end to the fatigue design process either. Verification has to be absolutely thorough. If you don't test the item, which is for public use, by simulating real world conditions, you can be held guilty of negligence.

This is the flowchart that the SAE likes to follow for designing against fatigue. Observe that the word "modify" shows up in three different spots.

How safe do you want to be? I hear that something like one major air accident everyday is considered a 99% safety rate as far as air travel goes. Anyway, the company Crank Brothers has babysat the individual in question with a new pair of Candy C's. Everything is safe. Don't you worry, here's a band-aid. This was just another outlier.

* * *

Alex Moulton Explains His Design Studies

noreply@blogger.com (Ron) — Sat, 07 Aug 2010 05:20:00 +0000

Dr. Alex Moulton is a source of inspiration for me as a young engineer. I encourage you to watch these videos to see how a great mind thinks. The message couldn't be clearer. Good engineering is a hands-on job. If his biography weren't so expensive, I'd voraciously consume the book in one sitting overnight.

RELATED READING :

Mark Sanders Explains His Strida Concept
Design Case Study : Innovation Of The Brompton Folding Bicycle

Johan Museeuw Trained Hard

noreply@blogger.com (Ron) — Tue, 03 Aug 2010 15:03:00 +0000

A man who knew how to train properly to overcome adversity was Johan Museeuw. He was known for his gradual approach to training, his belief in his training ideas and his ability to focus on training so he could return to racing when his cycling career seemed to be over - a couple of times.

A wicked crash on the slick cobblestones of the Arenberg Forest in the 1998 Paris-Roubaix, the queen of one-day racing classics, almost ended his career. Gangrene set in because of improper cleaning of a knee wound by medical personnel, and they almost had to amputate the leg. As it turned out, they didn't amputate the leg, and Museeuw responded by recovering, training and coming up with a win in the 2000 Paris-Roubaix. Tragedy struck again when he crashed on his motorcycle in the summer of 2000. He fought back yet again for another Paris-Roubaix win in 2002, among other victories.

Museeuw's glory started in a small way, but he kept stretching his personal limits. In his first race outside of Belgium, the Tour of Austria, Museeuw finished the first stage 30 minutes behind the winner. He was alone, numb from the cold, and reportedly crying on his bike. He did not abandon the race though. In the same manner, he would continue to break down barriers during the remainder of his career - with dogged determination.

Museeuw was infamous for training alone for periods as long as 4 months. He knew his specific training goals would not be achievable in large groups. He would ride ruthlessly into the wind for hours on end. When he adopted heart rate training later in his career, he took himself into the red repeatedly on hard days, for unbearably long periods. He would impose kilometer per hour "basements" on some training rides - on the order of 43 kmph (27mph) - and he'd refuse his body when it told him to slow down.

Museeuw's good friend and teammate (and world class racer in his own right) Wilfried Peeters says of Museeuw, "Out of 100 pros, 95 won't be able to deal with Johan's training rhythm. A young rider who tries to constantly keep up with him will, so to speak, destroy his body. Johan has both the body and the willpower to work those heavy training schedules. He sometimes has some riders that live in his region ride with him, but very few can keep up for a few days in a row."

Peeters explains that after brutal group training rides, Museeuw would ride another half hour extra, because it was mentally very important to him.

These words were from the book Cycling Fast by Robert Panzera, a USA Cycling certified coach and NSCA-certified strength and conditioning specialist.

In order to stay a bit more objective on the subject of Johan's superhuman performances, I will also include the fact that he was imprisoned (suspended) for 10 months for allegedly using human growth hormones and other substances to boost his strength, red blood cell count and recovery time. He had stood trial for his part in a ring alleged to have funneled EPO and other doping substances from a Belgian veterinarian to pro riders.

Turns out, critical reading is essential when reading any glorified literature about any athlete these days. Its an utter shame.

* * *