Contenders Line Up To Take Top Prize
New for the 2012 North American Handmade Bicycle Show is the Gates Carbon Drive Frame Design Contest, which challenges custom builders to design a frameset that incorporates a carbon belt drive system.
The contest, sponsored by Gates, a 2012 NAHBS sponsor, offers a top prize of $2500 cash and ten carbon drives (worth $2500) to the first place winner, ten carbon drives for second place, and five carbon drives for third place.
When you consider that a belt drive cannot be broken and reassembled like a chain can, the primary challenge for the framebuilder is to design a frameset with chain or seat stays that can be disassembled for installation, and for those (rare) occasions when the belt needs to be replaced.
Rob English, of Eugene (OR)-based English Cycles agrees with this assessment. “The unique thing is allowing the rear triangle to split for installing the belt. Otherwise, it’s pretty straightforward apart from paying attention to allowing for a straight belt line,” English says.
John Caletti of Caletti Cycles in Santa Cruz, CA elaborates further about the design challenges: “The chainstay length has to work with the gear ratio used and the cog sizes and belt length needed to get there. Also, the cog up front is large and wide so the chainstays have to be kept out of the way. The newer center track version is narrower and can be placed further out.”
About the frame split challenge, Caletti says: “I like to use the Paragon Slider dropouts with their integrated chain tensioning and wheel location adjustments for easier setup and no wheel slippage.”
Both Caletti and English have designed and built belt-driven bicycles before, and both offer the option on their custom menus.
Although the contest only allows one entry per framebuilder, Rob English plans to keep more than one belt-driven bicycle in his stable at NAHBS.
”Actually three of my bikes at NAHBS will be carbon-driven!” says English.
In Part 2, we’ll look at the design approaches of a few other builders, and explore some of the applications of belt drives (hint: they’re not just for commuting anymore).