The non-Ibis approved “brototype” 27.5-inch Ibis Tranny.
Ibis Tranny 27.5
One of the oddball bikes at Sea Otter this year was a non-Ibis endorsed, unofficial “brototype” Ibis Tranny built by Tim Cannard. Using a modified rear triangle with added clearance on the chainstay and seatstay bridges, this modified Ibis Tranny had plenty of room to run Ritchey Vantage WCS 27.5 wheels and 2.1 Ritchey WCS tires. The front Fox fork is a 26-inch model, but has a tall enough bridge to clear a 27.5-inch wheel.
Even in 26-inch guise, the Ibis Tranny is still one of the most nimble, quick and agile hardtails out there, featuring geometry that’s more like a dual slalom bike than a cross-country race rig. This relaxed geometry gives the Tranny exceptional handling characteristics, especially going downhill. And with the slightly larger 27.5-inch wheels, it takes all the greatest attributes of the Tranny and enhances them.
Although not officially approved by Ibis, the bigger wheels of the Tranny 27.5 further enhance the superior handling of this versatile hardtail.
The Ibis felt more comfortable downhill than the new Focus or Scott 27.5s we rode, soaking up choppy sections of trail with ease. Uphill, the Tranny felt slightly slower to accelerate than its 26-inch counterpart, but still far quicker than 29ers I’ve ridden. Although the Tranny was not designed for 27.5-inch wheels, measurements are still within the specs of 27.5-specific frames like the Focus. Bottom bracket height on the Tranny 27.5 increases about a half-inch to 12.5 inches, which is the same height as the Raven 650b.
Rear triangle was clearance for added space to fit a 2.1-inch rear tire.
Right now Ibis has no plans to offer a Tranny 27.5, but the exploding popularity of this tweener wheel size may pump new life into the 26-inch Ibis hardtail. It’s a concept that works, and in the ASS’s completely biased opinion, the Tranny 27.5 felt more comfortable, stable and agile at speed and cornering than either the 27.5-specific Scott or Focus.