Get Gnarly On Your Own Homemade Gravity BikeWritten by mike on September 23rd, 2011
Take a bike with no pedals and a super low center of gravity, head to the top of the tallest hill you can find, and let gravity do the rest. Gravity biking, kissing cousins with downhill skateboarding, is a niche sport that attracts extreme racers who are happiest when they average 50mph and peak out as high as 80mph.
The details from his writeup:
The basic standards are:
Wheel size – 51cm / 20” max
Bike weight – 34kg / 75lbs max
Axle to axle length – 127cm / 50” max
Many more rules can be found in the rule book. But where we race, none apply
Tools needed or have access to:
Metal cutting tools of some kind – Angle grinder and cut off wheels, metal band saw, hacksaw, hole saw.
Assortment of wrenches
The more the merrier!
We dig through metal scrap bins for most of our metal material and then let the material inspire.
We did buy 8ft of .75″ x 1.5″ x .125″ mild steel for this project.
x2 20 inch wheels
Old bmx bike to pluck any tid bits from
More resources can be found here: