Long Term Test: 2015 Ibis Tranny 29
Since receiving an Ibis Tranny 29 in late June, I have flown with it from Alaska, raced it in the Downieville Classic, and in the ultimate test of durability, rode it for a week straight across 425 miles of grueling terrain with 47,000 feet of climbing between Lake Tahoe and San Francisco. There is no doubt that I have put this carbon fiber 29-inch hardtail through the ringer, and the Tranny 29 has performed flawlessly the entire way.
There are numerous endearing qualities to the Tranny 29, but none greater than its versatility. The Tranny namesake comes from the inherent transitional capability of its design. Because the rear triangle can completely separate from the front triangle, the Tranny 29 is an ideal travel companion that saves its owner from having to pay the extortion of bicycle airline fees.
Traveling home from Alaska this past summer, I packed the entire bike into a Ritchey Breakaway suitcase, and check it as regular luggage. To ensure that I didn’t overstuff the bag, I took the rear triangle and put it into my carry-on, easily packing clothes around it. The process is so dialed now that I can build or break down the bike in less than an hour.
Unlike other travel bikes that sacrifice weight and handling for traveling convenience, the Tranny 29 sacrifices almost nothing in frame weight, coming in at a scant 3.08 pounds. The Ibis Slot Machine chain tensioning design further enhances the Tranny’s versatility, using a sliding box behind the bottom bracket that allows it to be run as either a single speed or a geared bike.
In order to include the Slot Machine feature while maintaining its short and nimble rear end, the Tranny 29 features asymmetric chainstays. As a bonus, a gap in the rear triangle seatstay wishbone where it meets the front triangle allows it to run a Gates Carbon Belt Drive system, the standard drivetrain when you order the “Unchained” build kit from Ibis.
The 142×12 Maxle rear thru-axle greatly improves rear wheel stiffness—an especially important factor with inherently taller and flexier 29-inch wheels. But the Tranny 29 thru-axle featured another hidden benefit I discovered on our 425-mile trek. To keep up with my geared mates, I ran a chain-driven “dingle”speed setup, enabling me to change between a 32:20 climbing gear and a 34:18 flatland gear, using the same chain length without having to re-tension the Slot Machine. Thanks to the thru-axle, all I had to do was loosen it and pull it halfway out to generate enough slack that I could change over to the other gear without the wheel ever leaving the dropout.
Versatility in Setup
Another aspect of the Tranny 29’s versatility is in suspension and dropper post setup. The Tranny 29 is designed to run either a 100mm or 120mm suspension fork depending on handling preferences and terrain. I opted for the 120mm setup, which gives the Tranny 29 a 12.3-inch bottom bracket height and 70 degree head angle, making it stable and comfortable on both climbs and descents. The rear triangle is designed to run tires as wide as 2.3 inches, and when combined with a 120mm fork and a dropper post, the Tranny 29 suddenly becomes a lightning quick and capable all-mountain hardtail.
Thanks to internally routed cabling in both the top tube or full stealth cable routing through the down tube, the Tranny 29 can cleanly accommodate dropper posts like the KS LEV with external cable setup or a fully stealth RockShox Reverb post.
Those planning to use the Tranny 29 as a geared bike can easily route full-length derailleur cable housing through the front and rear triangle for better shifting performance, and the cable routing ports can be unbolted from the frame to remove some of the frustrations inherent to internal cable routing. For those running a front derailleur, a direct mount setup keeps things clean and light. Thankfully, the folks at Ibis put function before form and kept the rear disc brake cable routing external so you don’t need to bleed the brake to install it.
Continue to Page 2 for more on the Ibis Tranny 29 and full photo gallery »
The post Long Term Test: 2015 Ibis Tranny 29 appeared first on Mountain Bike Review.