It wasn’t more than a couple of years ago that the idea of pedaling a 6in bike on a fifty mile high country ride would have been pretty unappealing. Sure, it could be done- but that category of bikes’ descending capability was all too often outweighed by their heft and pedaling inefficiency. Nowadays, it seems like every manufacturer has a sub-30lb 150mm wunderbike- some of which are actually go anywhere, do anything machines.
BMC’s Trailfox TF01 is just such a beast. Its suspension travel, front and rear thru axles, dropper post, and laid back 67.5 degree head tube all promise a good time going down. Its carbon fiber front and rear triangles, steep 73.5 degree seat tube, and 28lb on-trail weight (including pedals, tubeless tires, a computer, a bottle cage, and 4 scoops of Stan’s sealant) all suggest a bike that doesn’t need–or want–lifts in order to gain altitude. Can it be both? Hit the jump to find out!
It was at BMC’s Fourstroke launch this summer that I first got the chance to spend a couple of hours on the company’s Trailfox platform. 
Designed as sort of a ‘big days on big mountains’ bike, the Trailfox TF01 is the 150mm travel version of the company’s Advanced Pivot System virtual pivot platform, rendered in handsome unidirectional carbon fiber. The test bike shown here is a 2012 model- 2013 models have a handful of well-chosen upgrades that are called out below.
The Swiss company’s distinctive seat cluster is present, supporting the seat tube and clearly identifying the bike as a BMC. The T-shaped top tube is similarly distinctive and a series of bosses for P-clips makes for clean dropper cable routing (the 2013 model takes advantage of Rock Shox’s Reverb Stealth for an even cleaner setup). My wobbly knees would smack the high and wide top tube for the first few rides–not uncommon with big carbon tubes–but there’s nothing like a series of bruises to correct one’s form. The massive down tube is protected from flying rocks by a nice rock guard-cum-cable guide.
The smoothly molded single-piece rear triangle takes advantage of an increasingly-standard 12mm thru axle. The native post mount brake bosses are for 180mm brakes or bigger- no bad thing, especially with the spec’d (non “Trail“) Avid XO brakes. It’s only the limited tire clearance that has us scratching our heads and running a 2.2in rear tire in most conditions- anything bigger would be awfully snug in sloppy conditions.
The front and rear are connected by a pair of stout co-rotating aluminum links, the top of which for 2013 drives a Float CTD Performance rear shock. Not dissimilar to Giant’s Maestro platform, BMC’s Advanced Pivot System incorporates a small–but critical–amount of anti-squat. 
It’s the anti-squat that I’m convinced is the secret to the BMC’s awesome climbing ability.
That’s right: Awesome. Climbing. Ability. The Trailfox isn’t a climber in the overdamped, fire road optimized way that too all too many bikes are. And the slack head tube can be a bit of a handful if the Fox TALAS fork isn’t dropped when things get truly steep. No, it’s one of those rare how did I clean that bikes. It was on a brutally technical local climb–the kind that you don’t ride on an off day–that the BMC’s climbing ability truly struck me. Rather than bogging down under power, the BMC sits up ever-so-slightly, allowing it to surge forward over steps and roots. The theoretical tradeoff is some pedal kickback, but I never noticed it- let alone found it to be a problem. While the slack head angle can cause the front wheel to wander, the steep seat tube helps to keep weight forward and that tendency in check. In short, there’s no way that this bike should be as slack and active as it as while climbing as well as it does.
But few of us really read about 6in bikes to find out how they climb. After all, such long legs are really designed to make the most of descents. 
Unsurprisingly, the Trailfox is an immensely capable and confidence-inspiring descender. Far from making the bike sketchy or nervous, the Trailfox’s light weight encourages playfulness and rewards an involved riding style. Where some bikes can feel determined and simply plow through rough patches, the BMC floats. Precise terms, I know, but the Trailfox is a bike with truly engaging character.
The only fly in the ointment has been the stiction-riddled and horrifically overdamped 2012 Fox TALAS fork. Long stickier than their fixed-travel brothers, the TALAS isn’t helped by Fox’s FIT damper, which hasn’t done anything for small bump compliance and is completely outmatched by the BMC’s lively rear end. Against Fox’s advice, we’ve taken to swapping out the damper oil on other FITs for something lighter (depending or rider weight) and been much happier. 
The little time we’ve had on 2013 forks indicates that they are much better in most conditions. We also did manage to blow the ’12 RP2 rear shock within the first 200mi- that was repaired under warranty and a replacement is on its way (2013 models use an updated shock).
The “XO” in this model comes from the SRAM XO kit including brakes and for 2013 a 24-38 double crankset and rattle-free Type 2 rear derailleur. Finishing kit comes from Easton in the form of Haven aluminum wheels and a Haven stem and carbon bar. A RockShox Reverb Stealth seatpost sweetens the $6,700 deal. The same frame is available with a Shimano XTR/Haven Carbon build while carbon/aluminum and all-aluminum models come in at lower price points. Tubeless-ready tires would be nice to see and I immediately recognized the Fi’zi:k Tundra 2 saddle as an instrument of the devil- but personal and regional preferences do vary. Don’t worry- the 3D Violet accessories are not stock. Overall, the build kit leaves almost nothing to be desired- and the 2013 model even less.
Given the big mountains that characterize BMC’s home country, it should be no surprise that the Trailfox is as capable as it is. After about a month together, the Trailfox has been welcome on every ride it’s been on- from 2hr hammer sessions to 8-hour epics. It wouldn’t be my first choice for tight, woodsy singletrack, but the Trailfox has been as at home on loose, rocky New Mexico trails as it is on the big climbs and descents around Durango. A rare bike that encourages creative and adventurous lines on the descent, the Trailfox TF01 also manages to be remarkably flattering on the climbs. It may be too early to call it love, but it’s safe to say that I’ve got a big, fat crush on this bike.
marc
