Could Trek’s Stache be the plus-size playbike we’ve been waiting for?
WHY IS THIS A SUPER BIKE?
- Trek’s sliding Stranglehold dropouts offer 15mm of chainstay length adjustment (405-420mm) and can accommodate 650b+, 29in and 29+ wheels
- Boost technology helps to create stiffer wheels and allows more clearance for wider tyres
- Wide rims, wide tyres and big 29in hoops mean the Stache can tackle just about anything in its path
Just when we thought we were getting on top of all the wheel sizes the industry has thrown at us, along come ‘plus-size’ bikes andmyriad new dimensions to get our heads around. While we’re seeing most manufacturers settle on the more conservative 650b+ standard (2.8-3in tyres on wide 650b rims), some like to push things that little bit further.
Trek are one such company, and they’ve thrown their considerable weight behind the larger 29+ format (3in tyres on wide 29in rims) with the new Stache hardtail. Why opt for the bigger of the two ‘plus’ sizes? “More rollover, momentum and traction, equalling a confidence inspiring, super-capable ride,” says Chris Drewes, Trek’s MTB Hardtail Product Manager. “Twenty-nine plus delivers a more pronounced benefit, especially for hardtails. The same gains going from 26in to 29in wheels are realised in going from 650+ to 29+.”
Squeezing it in
Packaging big wheels in a frame that maintains the lively feel everyone yearns for isn’t easy, so how do you fit even bigger wheels in place without waving bye-bye to decent handling? As you can see, the Stache sports an elevated driveside chainstay. Though this means saying adios to the front mech, this design – combined with the new SRAM-backed Boost hub standard (15x110mm front, 12x148mm) – has enabled Trek to keep the back end of the bike short even with a 3in tyre in place and maintain a lively feeling on the trail.
It took Trek numerous attempts to create an elevated stay that offered the right combination of stiffness and clearance. But that wasn’t the end of it. We all know that trails rarely stay bone dry, especially here in the UK, so decent mud clearance was essential too. Drewes says: “Look at the non-driveside chainstay and you’ll see that we have a one-piece forging of the bottom bracket and part of the chainstay. This allows us to maintain stiffness and proper clearances. Look even closer at the underside of the bottom bracket and you’ll see a carved-out notch to optimise clearance for mud and tyre.”
Then there are the ‘Stranglehold’ sliding dropouts at the rear. These allow you to run the Stache with a slammed 405mm chainstay length, but only if you’re running a 27.5x3in or 29x2.35in rear tyre (this does mean you’ll need to use a longer travel fork up front to maintain similar geometry though). Chris claims this setting “yields a very playful ride, which finds the rider lofting over obstacles and popping off jumps”. Lengthen things to the 410mm mark and you’re entering 29x3in tyre territory. Slide the Strangleholds all the way out to their final 420mm setting and, although the chainstays are still extremely stumpy for a big-wheeled bike, you’re in for a more stable ride.
Suited and booted
Tyre and rim choice on plus-size bikes is critical and can make or break the ride. Trek have kitted the Stache 9 out with SUNRingle’s Mulefut 50SL rims, which boast a 45mm internal width, and meaty Bontrager Chupacabra 3in tyres front and rear. Drewes explains: “We spent a lot of time riding rims with internal widths of 30mm all the way up to 46mm. We tested six to seven different rims and four different tyres (which is all that was available). We found that the optimal width for a 3in tyre, balancing rim weight and tyre support, was between 39 and 46mm internal”.
Chris continues: “With a larger contact patch, the tyre tends to want to twist during harder cornering or over large bumps. Instead of overbuilding the tyre sidewalls you can add a few millimetres of rim width and have a significantly better overall system.”
Don’t believe the hype?
While some people may have negative preconceptions of plus-size bikes, those who’ve tried the Stache in anger have been suitably impressed. Tom Marvin, technical editor on our sister mag What Mountain Bike, says: “It’s a bike that, despite some flaws, is really difficult to dislike – far more fun than it should be.”
SLACK ANGLES
With a 110mm (4.3in) travel fork in place, the Stache has a claimed head angle of 68.5 degrees and a BB height of 328mm, which isn’t bad considering the whopping hoops fitted in place.
ELEVATED STAY
By making the frame single-ring only and lifting the driveside chainstay, Trek have managed to comfortably fit a 29in wheel and 3in tyre into the rear end while maintaining a fun and playful ride feel.
BOOST HUBS SRAM’s
Boost standard uses wider spacing at the front (15x110mm) and rear (12x148mm) of the bike. This means wider hub flanges, better spoke bracing angles and overall stiffer wheels, plus more tyre clearance too. The small change in chain line can be corrected with a 3mm offset chainring.
BB FORGING
It’s not just the elevated chainstay that allows the big wheel and tyre combo to work. The one-piece forging of the bottom bracket and part of the non-driveside chainstay, along with a carved-out notch on the underside of the BB, means there’s enough room for the 3in rubber and some mud.
TYRES AND RIMS
Most brands seem to agree that the sweet spot for plus-size tyres is between 2.8 and 3in. Trek’s in-house parts brand Bontrager created the Chupacabra, which measures in at 3in. On the Stache, this is paired with SUNRingle’s Mulefut rim, with a 45mm internal width.
ONE-BY SPECIFIC
When SRAM launched their 1x11 XX1 transmission a few years back it provided a wide enough gear range that there was no need for a second or even third chainring. This meant designers were no longer restricted by having to find room for a front mech and could experiment with frame shapes.
PRICE 4200$