New Wheels

Posted: 23rd August 2010 by Nigel in Miscellany

After riding WhamBam a few times, it has quickly become apparent that there is not enough ground clearance under the pedals when cornering. This was due to the fact that we didn’t use a jig when assembling the frame. I made plenty of calculations for the appropriate geometry, but in the end, we more or less had to eyeball the angle between the forward triangle and the chain stays. The clearance is not too bad, except for the fact that I was intending the bike to be a fixed gear, which doesn’t allow you to coast with the outside pedal down during hard cornering. This left me with two options, either go with shorter cranks, or scrap the fixed-gear idea. I went with the later option.

My first thought was to swap it over to a single-speed, especially since the wheelset I was using already had a flip-flop hub and a freewheel on one side. However, this would require building a brake mount into the seat stays, which would apply a force right in the middle of the seat stays, perpendicular to the load they were intended for. The would probably be strong enough, but without load testing, I wouldn’t really be comfortable with that setup. Imagine the¬†catastrophic¬†failure potential: blowing out the seat stays under heavy braking… not good.

So then I settled on a coaster brake, which would require a new rear wheel. This is the result: