The big story at the 2015 Sea Otter Classic is the widespread introduction of the 27.5+ wheelsize. For those unfamiliar, this is a mid-fat wheelsize featuring approximately 3-inch tires. Stay tuned for a more detailed analysis of this progression in the plus size trend once the show has finished.
The Trek Stache reviewed here is 27.5+ compatible, but the bike I tested was running 29+ wheels/tires.
The aluminum-framed Trek Stache is designed to work with 27.5+, 29″ and 29+ tires, thanks to the Trek Stranglehold dropouts. The stock option is 29+.
In order to adequately accommodate the 29+ or 27.5+ wheels the Stache features SRAM’s all-new Boost 148/110 rear/front hub spacing and related components. This provides stiffer wheels, improved chain/tire clearance, and shorter chainstays. In fact, these are the shortest chainstays that Trek has ever engineered–405 to 420mm (presumably depending on where you have the dropouts set).
The Stache 9 is in the trail hardtail category of bikes, with a 67.5-degree headtube angle, the super-short chainstays mentioned above, and 110mm of fork travel.
As for component spec, the Stache comes with SRAM’s X1 drivetrain, the new Manitou Magnum 29+ Pro fork, KS Dropper Post, and Bontrager’s Chupacabra tires.
Perhaps one of the most interesting things about the frame design is how exactly Trek got that chainstay length so short. In order to shorten the chainstay as much as possibly they created an elevated chainstay on the drive side in order to route above the crankset, around the wheels, and over the derailleur. As you can see from the photo, there’s significant chainring/tire overlap, which just wouldn’t have been possible with a standard chainstay:
Out on the Trail
I got this rig out for a real-world test at the Sea Otter Classic, and the assertion by Trek that this is a “trail hardtail” is spot on! Despite the plus-sized 29″ tires this may be the easiest-to-wheelie bike that I’ve ever ridden, thanks to the uber-short chainstays. Seriously, just smack the pedals and wrench the bars and that front end flies off the ground!
Also, I found the actual on trail handling to reflect this as well. Thanks to the slack head tube angle the descending was confident and stable, and the cornering was aggressive thanks in part to the addition of a dropper post.
As you could expect, the traction through sand, on the climbs, and in the corners was excellent thanks to the plus-sized tires. Aside from the Surly Instigator I think this may be the most aggressive non-standard mountain bike that I’ve ridden, and coupling the incredible plus-tire traction with aggressive geometry is a match made in heaven! My only question is: why doesn’t this rig have rear suspension?!
The “trail” category is also climbing-conscious, and the epic traction of the plus-sized tires shines again. When it came to stupid-steep, borderline unsustainable loose-over-hardpack climbs at Fort Ord, the only hiccup in the system was my fitness and not rear tire traction.
While I want to totally love and embrace this bike, I just can’t. There was one big hangup that I experienced: my quads and calves both banged on the seatstays constantly. Any time I started to descend or corner aggressively I’d bang the stays on my calves and inner thighs, depending on the position and part of the pedal stroke I was in. Even when seated, my thigh just above the knee would sometimes impact the stays when digging deep in my pedal stroke.
In my opinion, this should never happen on a bicycle. The Trek tech that I spoke with at the booth said, “well, maybe it’s because it’s a fat bike.” Well yes, I’ve ridden a fat bike that has this issue: the Borealis Yampa. (Granted, this issue isn’t nearly as pronounced with the Stache as it is with the Yampa… but it’s still there.) However, I’ve ridden 4″ fat bikes that don’t have this issue, 5″ fat bikes without this issue, 26+ bikes without this issue, and 29+ bikes without this issue.
While I realize that the stays do have plenty of room built in to accommodate a variety of tire sizes, as I said, I’ve ridden two 29+ rigs (Surly Krampus and Niner ROS 9 Plus) that don’t have this issue. To say that this is a result of the plus sized tires is an absolute cop out. Granted this came from a tech at the show and not a brand rep, but regardless of what the justification is I won’t accept that a bike frame has to hit my body when I ride. I think this issue partly arrises from the slightly-flattened tube design. While it looks great, if it causes such issues, looks just don’t matter.
As both Corey and I mentioned with the Yampa, perhaps if you’re a tall guy riding a size-large frame and you have the wispy build of a cross country racer, this won’t be an issue. But this isn’t a bike designed for a cross country racer. If you’re a shorter guy with a stocky, muscular build like me (I’m 5’7″), unfortunately you can probably expect to run into these issues.
Honestly, not having the frame design figured out in medium and small frames (I rode a 17.5″ frame) is mind-blowing. If Trek didn’t know that this was an issue, I’d be shocked. If they did know it was an issue and they produced the frame anyway, I’d also be shocked. So I guess either way, I’m shocked to run into this issue from a company that generally produces such solid, dependable bikes.
While overall I think the trail handling is spectacular and the plus-sized tires perform superbly, having my legs hit on the seatstays is an absolute deal breaker for me, especially when there are so many other bikes on the market. If you’re tall and lanky, you may not have that issue. But if you’re short, buyer beware! Be sure to test ride before you buy.
Note: this review was originally written assuming that the bike was spec’ed with 27.5+ wheels. While you can mount 27.5+ wheels on this bike, the stock spec–and the spec I tested–features 29+ wheels. This was my mistake. I’ve modified the review accordingly, and updated it at 8:39pm MDT.