Crater Gravity Bikes

Gravity bikes now prebuilt for sale it seems.

2013-05-17T16:03:00.001-07:00

The design of this bike is pretty good and the fact that they make it available for sale is legit I don't like the bar position though. An update on my bike is I had a guy weld the seat for me but he welded it way too high now I have to cut it and re fab the whole thing.... That's what you get for cheap labor needless to say he didn't get paid oh well. I'll try to start posting info again on the gravity scene sorry I let this blog slide for so long things got rocky for me over the past year or so.

http://www.youtube.com/watch?v=7pkDxQK3bDc

Search+Win

2011-02-02T16:22:00.000-08:00

Ok well I know I haven't made any post about my GPV since I haven't finished it yet but I did just buy a new mountain bike a Specialized SL Pro and I'm totally stoked to get out and ride.

The following is completely off blog topic... Viewer discretion is advised...

Anyway I found an awesome program on the interwebz that you get points for doing searches and then turn in the points for gear for snow boarding or other stuff. so I'll give you guys the link so you can get started.
http://flow.searchpw.com/refer/megacrater

Gravity bikes in action

2011-01-15T17:24:00.000-08:00

This is not my video but it shows that gravity bikes are still around. You gotta watch the whole video it's really pretty cool.

My gravity bike so far

2011-01-05T18:49:00.000-08:00

I've started the build on my gravity bike and am planning on riding it for the first time this weekend if all goes as planned and the weather isn't too bad. Anyway I'll give you a little info on how I've been doing my build so far.

Frame - Is a standard BMX frame flipped upside down more specifically it's an old Bronco SE I found in my friends back yard a few months ago. Perfect for a first time gravity bike right? It's a little rusty and has some paint chips in it wouldn't be allowed in an IGSA race but who cares.

Brake Levers - Shimano SLX levers from early ninty's something I found around the shop I work at for cheap.

Brakes - I'll have to check in on the brands but for now two normal rim brakes one on each wheel.

Wheels - Both are front wheels. One is from an old TREK kids bike we found and the back is a bmx wheel a kid gave to the store owner. I inspected both to make sure they ran solid before I put them on. Soon I'll be switching the front wheel for a Nylon Mag for added weight.

Tires - The tires I have on currently are an old pair of Tioga Comp Pool Slicks 20 x 1.75''
Watts measures the rolling resistance that these slicks create at each PSI level. Naturally the higher number of watts is worse.

PSI

100

120

Watts

34.3

25.1

21.6

18.9

17.4

Stem(s) - I have 2 stems on my bike currently, one to hold the modified handlebars we've made just a standard BMX stem that came on the frame when I found it. The second is an old mountain bike stem that I have put where the seat post use to be so I can put some knee braces on. (fancy huh?).

Handle bars - What we used for the handlebar part was an ape hanger style bmx handlebar we modified the bar by cutting off the top flat crossbar and used just the U part of the bar. Also we modified a set of old drop style road handlebars to create a kneebar to put in the seatpost stem.

Handle Bar Grips - I've decided on going with a set of Primo Martinez grips that I bought a few years back to add some extra comfort to the bars. (animal grips used in bottom pic)

Sorry about shitty quality of the pics I'll get some better pictures as I finish the build.
Extra Specs:
My wheel base (axle to axle) on this bike is at 101cm.
20'' wheels Front and Rear.
First three numbers of serial # are 999 but if read from front of bike it's 666. (good sign right?).

Need to do still list.
Add rear pegs for a place to rest my feet while riding.
Add Primo grips.
Add weight to frame for faster top speed.
Cut kneebar to my liking so I don't have hideous long kneebar.
Paint frame for a more aesthetically pleasing look.
Possibly add seat?
TEST RIDE

IGSA Rules

2011-01-04T20:55:00.000-08:00

Seen my blog or some random information about gravity bikes and want to know if there are real rules to abide by?

Well you're in luck! Just incase you wanted more rules to listen too I have the official International Gravity Sports Association rules!

If you're planning on racing professionally there's your resource to make sure you wont get turned away from competing.

On the other hand if you're not planning on being professional about the whole thing get shitfaced with your friends and spend thirty hours planning on how to do it the original way. . . How ever the hell you want! Plus you can always use the IGSA rules as you know guidelines. Isn't that what they're supposed to be anyway?

Always remember stay safe, wear protection And NEVER drink and drive. Happy Building!

Oh ya and I can't forget the link to the IGSA site for "references" Yeah. . .
http://www.igsa.com/

Oops ^ wrong one maybe try the next one.
http://www.igsaworldcup.com/

Gravity Bikes, What's getting me started?

2011-01-04T19:36:00.000-08:00

For the past few weeks I've been building my own personal Gravity Powered Bicycle. Until a few weeks ago I had never seen a gravity bike or even heard of one. So what got me started building one and got me so obsessed to go out and make a blog about them?
Recently while at the bike shop I work at my boss was talking to a couple kids that go to the local College he noticed that one of them was holding a longboard. So he commented on it and brought up the fact that he thought they weren't his style but he had a GPV that he made in the early 80's. Neither of them knew what a GPV was and I had no Idea either so off he went to retrieve it from the stores basement. After a minute or two he resurfaced with on of the most interesting bikes I've seen. He called it his Basin Racer basically he used an upside down BMX frame, some MAG wheels, and some very interesting modifications to various other bike parts. After he demonstrated how he road it and telling us his fastest time on the bike was 45mph (recorded) I told him that I had to get in on this (being the curious crazy ass that I am). After bringing it back to life with freshly greased bearings and new tire slicks we decided to close the shop early and take it for a spin for the first time in 20 years. We took it out to sandeo hill (the only hill within 20 mins of us) it has about a 5% grade the first run we did my boss hit 40mph and the second run he hit 46mph (beating his previous recorded record). So we went back to the shop and decided that we need to build me one so here I am building my first one to set my own speed records.

What's a GPV/Basin Racer?

2011-01-04T18:57:00.000-08:00

A GPV (Gravity Powered Vehicle) in this instance it is in the form of a bike. These bikes have many designs and come in many different forms but proper ones follow these guidelines. No driving chain, cranks, sprockets, or chain rings. These bikes are solely meant for going downhill as fast as possible. The idea first arose in the early 80's in California back then it was something to do for fun guys would build their own gravity bikes from any random bike parts that they could get their hands on trying to build the fastest racer for the cheapest price typically from old BMX frames. There were many guys that would show up to these unofficial events and race what they had, basically there were no rules except race what you brought. Some had fairings, some had added lead to random parts for the extra weight. Eventually the cops found out and tried to stop it giving tickets to riders from impeding traffic for going to slow, speeding if going to fast, and no headlights for night runs. Eventually the gravity bike craze mostly died out. . . or did it?
In the late 80's BMXplus had an article about the craze which inspired many BMX riders from all over the world to ride. One rider (Jared Hanebrink) was featured in both the BMX Plus and later the Action Now magazines for GPV riding with his full fared gravity bike (No. 1, photos below). Dan Hanebrink became a big name for gravity bikes pretty soon after the beginning eventually riding his fully fared gravity bike in the 2000 X-Games when it was featured as a demonstration sport.

Photo's taken from an old issue of "Action Now" Magazine