NAHBS 2012 – Priority Cycles’ Insane Dual Drive Carbon DH Bike Prototype
The prototype DH bike above was made for HippieTech suspension founder Jerry Vanderpool, who will be racing it all season, including at Sea Otter Classic, to test it. Then, Priority Cycles’ builder/owner Damon Madsen wants to put into production. It’s pure prototype, as you’ll see from the rough construction, but it’s totally sick. We’re talking dual drive inside the front triangle, left-hand belt drive and right-side rear disc brakes. Here’s how it works…
Because the swingarm’s single pivot is so far forward, the rear wheel has a virtually vertical axle path. That allows room for a seatstay bridge with about 1.5″ of space left between the tire and seat tube at full compression.
Design uses an Alfine 8-speed hub as the gear cluster with left side belt drive and full floating brake on the right. Took six months to build this first version.
Has 8.25″ of travel, comparable to most World Cup-level DH bikes on the circuit. The suspension gets its leverage ratio via several links and arms. (A) connects the swingarm to a connection link, which contacts the shock linkage at (B). The shock link’s (or whatever you want to call it) main pivot is (C).
Belt is really loose to allow for chain growth, but it’s tight at full extension. Chain tensioner rollers on the front and rear cogs keep it in place. I love that they’re spaced using Avid’s CPS washers on the rear.
Priority’s regular bikes have a redesigned linkage and swingarm to make it stiffer and give it a better shock curve. His designs use a 2:1 shock ratio. New carbon linkage came about because he was out of aluminum and had some carbon laying around.