Archive for January, 2012


Sunday, January 29th, 2012

This may seem like deja vu all over again, but belt drive fever continues with this single speed MTB for Dawson. It all started with a lovely Phil hub with belt-drive single speed cog – the challenge was to build a bike around it. And here it is:

He’s running a SID fork, Avid Elixir brakes, and a 39/24 ratio.



The tricky thing about single speed belt drives, as discussed before, is that you have to be pretty certain about what gear ratio you want. I have to calculate the precise chainstay length based on the front sprocket, rear cog, and belt length – unlike a chain, you can’t just add or subtract a link; there are a finite number of belt lengths available. Fortunately Dawson is an experienced single-speeder so he knew what he was looking for. As with Matt’s Alfine belt drive, we used the Paragon sliding dropouts with the frame-break option. This makes assembly very straightforward, and provides an integrated tensioner which makes setup a snap. Here are some pictures of the frame in progress. The tubing is True Temper OX Platinum, with Columbus Zona seat stays.


Next up: Bobby’s S3 club racer, Mike’s rando ride, and another Bobby’s re-imagined Rhygin!

Circle A Cycles   |   523 Charles Street   |   Providence, RI   |   401.831.5221
background: jared spinning on his circle a flatland frame. (reveal)

circle a