It’s just getting dark and we’ve literally just finished building our Ibis Tranny long-term test bike. For those who don’t know, the Tranny is the first carbon hardtail from US manufacturers Ibis, and it’s special because it’s designed to be used geared or singlespeed.
Not much new to that concept, except that Ibis have taken a fundamentally different approach to the frame. The Tranny has a two-piece frame, made of high-modulus carbon fibre. The junction between the two ends is just behind the seat tube. An arrangement of slots and two 5mm Allen bolts allows you to change the length of the rear end.
On a geared bike this simply allows you to control chainstay length (go long for stability, short for better climbing). But it’s for singlespeed builds that it really comes into its own. Join the chain to the correct length, then slacken the bottom bolt (just behind the BB shell), press down on the saddle and voila, the rear end slides rearwards and perfectly tensions the chain. Tighten the bolt to set it, and it’s job done. You’re left with a very clean build and no drag or rattling from extra tensioners.
We’ve built ours singlespeed to begin with – have you seen the transmission-eating weather? – and while some of the bits will get swapped about to fine tune it for specific conditions, the general build will remain. We’re going to fit the new Hope XC brakes, a Truvativ Noir SS crank, Schwalbe Dirty Dan tyres… but all that can wait. We’re itching to get out on it right now and it may well get a night ride this very evening. More soon, we’re heading off into the rain to begin logging miles…