BMC Speedfox SF02 XT - Review

BMC hails from Switzerland, a place where everyone seems to approach life in a slightly different way than the rest of the world. Somehow, the Swiss have blended timeliness and order with some of the most wild and spectacular landscapes to be found on the European subcontinent. This is a modern society, tucked between mountains and massive vertical cliffs carved during the Ice Age, where church bells ring out the work day, dairy cattle browse at ski resorts and beside Lego-colored manufacturing plants, which in turn are flanked by vegetable and flower farms. Cityscapes are punctuated by densely forested hills and flowers hang from the windows of multi-story metal and glass buildings. Viewed from above, much of Switzerland appears to be a manicured toy train set that has somehow sprung to life. Having spent time there, I would expect BMC's mountain bikes to look and ride differently than their counterparts in mainstream cycling, and they do, as witnessed by this week's test bike: the 130-millimeter-travel Speed Fox SF02 29er.



While its corners may be rounded off, the Speedfox's profile is angular and airy, with a rocker-driven Fox CTD shock that is positioned vertically to make room for a down tube water bottle. The frame's faceted and rectangular-profiled tubes are abruptly tapered and angled in sharp contrast to the present curvy and organic school of trailbike design, but it works. BMC's Speedfox looks modern and capable.

Details: Molded, screw-on plastic caps make for clean entries and exits for the Speed Fox's internal housing and hoses, and a thick, molded rubber chainstay protector ensures that the BMC will stay quiet on the downs. BMC tucked the post-mount rear brake caliper behind the seat stay for protection and the mount is dedicated to 180-millimeter rotors. Below the right-side chainstay is a simple pass-through chain guide, similar to the one which Specialized fits to its mid-travel trail bikes. As mentioned, the SF02 has an internally routed RockShox Reverb Stealth dropper post, which further cleans up the bike's already sharp appearance.



Sizing: BMC offers the Speedfox in five sizes, from X-small through X-large, and its dramatically sloped top tube should assist most riders to fit over the bike's 29-inch wheels, in spite of its 130-millimeter-travel rear suspension. Curiously, BMC lists every conceivable frame dimension on its geometry chart except the stand-over clearance for each size they offer. Our medium-sized model measured 29 inches (480mm) from ground level, to the top tube at the nose of the saddle, which suggests that the small and X-small frames may be on the tall side for diminutive riders.



Suspension: BMC calls it their "Advanced Pivot System," which is yet another fancy term for the dual-link, four-bar rear suspension which has become the fallback design for most of the industry. BMC's version drives a Fox Float CTD shock to produce 130 millimeters of rear travel. Short linkages cause rapidly changing leverage rates, which virtually guarantees that no two dual-link designs will perform exactly the same. BMC claims the middle path: a suspension that pedals well, brakes well and still manages to provide a smooth, controllable ride. Ambitious, perhaps, but not an impossible goal. Up front, the Speedfox relies on a 130-millimeter stroke Fox CTD Evolution fork, with 32-millimeter stanchions. Most trail bikes we were testing at the time had forks with stouter stanchions, so we were keenly interested in how well the BMC would hang with the burlier bikes at speed.

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The Speedfox accelerated smartly, and there were no arguments over how well the Swiss 29er tip-toed over Sedona's monotonous chatter. The BMC feels efficient at the pedals with and without the assistance of Fox's CTD low-speed compression lever. Get it moving and it settles into a fast pace over rolling terrain, where its cross-country rated fork and shock put in a surprisingly good effort to keep the bike travelling forward instead of up and down.

Climbing: Shimano's two-by XT drivetrain has a 1.5: 1 low gear and a 1: 3.45 top gear ratio, which is one click wider in both directions than a SRAM one-by drivetrain can deliver using a 30-tooth chainring (1.4: 1 low and a 1: 3 top gear), which is what I am accustomed to pushing on a big-wheel bike. Having a lower gear for Sedona's regularly stiff and technical climbs was refreshing. I could use more sensitivity on the pedals to get up and over tricky sections where otherwise I would be charging and hoping for the best. Paradoxically, we universally despised the way Continental's Mountain King and Trail King tires gripped in Sedona last season, but BMC's 29er seemed to showcase the tread pattern and we managed to find traction almost everywhere when we needed it most.

Stabilized weight transfer and a roomy cockpit kept riders well positioned over the bike for climbing. Point the Speedfox upwards and the rear tire feels naturally weighted, while there is just enough downforce on the front tire to keep it steering correctly for negotiating steeps. The BMC remained balanced as its rider transitioned in and out of the saddle as well. We attributed this to the 29er's 35-millimeter bottom bracket drop, along with the Speedfox's slightly steep, 74-degree seat angle, and its short (for a 29er) 17.125-inch chainstays (435mm).


Turning: Considering that BMC bills the Speedfox as a straight-up trail bike, its 70-millimeter stem is appropriate hardware for a medium-sized frame. It naturally weights the front tire when entering turns, which is a plus. The Speedfox is an easy bike to corner when traction is inconsistent, because both wheels tend to drift around about the same amount. Banking on that, its rider need not throw a foot out the instant the front wheel pushes over a slick spot, because the rear tire will drift about the same distance as it crosses that threshold and reset the bike on its intended line. Switching to a shorter stem, however, would speed up the rider's steering inputs at the handlebar, which may improve the BMC's tendency to take a wide arc around turns. 29ers need a few degrees more lean to get them to turn into corners as it is, but to hold a tight apex aboard the Speedfox, we found that we had to exaggerate the lean angle or counter-steer at the entries. A shorter stem would make those moves seem smaller and more intuitive.

Descending and technical trails: Steering forces were very light, which is rare for a 29er. BMC's choice of a 68.5-degree head angle, paired with the Fox fork's 51-millimeter offset was spot-on for the Speedfox's trail bike mission statement. I am sure that the slacker-is-better cult will wage war against that assessment, but those who actually are experienced bike designers know that "stupid" lies only one or two clicks beyond "just right." BMC is Swiss, after all, so we figure that they rode test bikes with steeper and slacker numbers, took notes, and eventually came to a stalemate between a 68 and a 69 degree head angle - thus, 68.5 became the choice.

Back on subject, our Speedfox felt more like a lightweight trail bike, so when the moment came to drop in on some of Sedona's more manly lines, it was with some trepidation that each of us rolled the front wheel over to the point of no return. Turns out, the BMC was quite a courageous descender, one that occasionally bested the more well-endowed enduro monsters that we had been riding, because it would deftly roll out of landings that appeared to be perpendicular to the front wheel. When we got bounced off line, we learned that we could trust the BMC to roll down almost anything what was in front of us. The fact that the 29er's bottom bracket lies significantly beneath the axles proved to be an asset on the rocks because it allowed us to confidently steer and brake down some impressive grades.



Where the big wheels did not help was when we had to yank the front end of the Speedfox up and over vertical ledges or climb abrupt faces. In those situations, and there were many in Sedona, The tall front end would literally be in our faces as the fully extended fork and 29-inch wheel filled every centimeter of available space between our forward leaning bodies and the impenetrable wall of stone that we were attempting to breach. Riders in excess of 1.8 meters (six feet) seemed to have better luck with the move because they could get their head and shoulders well over the handlebar. The Speedfox's ample front center and 70-millimeter stem caused the front end to feel heavy when lofting it over obstacles, which was not a serious problem if the rider compensated for it by either planning ahead or simply yanking harder on the bars.

Suspension: If the Speedfox did not have 29-inch wheels, this paragraph would have read like a disaster report. The larger and more comfortable rolling wheels, in conjunction with BMC's last minute decision to throw on massive, 2.4-inch Continental tires became the salvation for the Speedfox's suspension. 130 millimeters of travel sounds like a substantial number, but that is only a finger's width more than the paltry 120-millimeter cross-country standard that the industry is trying to escape from. At trail riding speeds, the Fox fork and shock manage quite well and the bike feels quiet and capable. The suspension kinematics don't seem to interfere much with rear braking, which further reduces the potential for back country drama. But, when the heat is up, the pads are on, and the fun meter edges towards the red line, the BMC's suspension is completely overwhelmed. To its credit, the BMC is still enjoyable to ride well past that point and it never becomes unmanageable at speed, but the ride is rough and the bike requires more concentration than that which is necessary aboard similar travel machines, armed with more capable forks and shocks. Outdated, perhaps, but the Fox 32 fork and Float shock should be commended for their reliability and versatility, the modern dual-suspension trail bike owes its very existence to them.


Component Report

BMC did a good job of spec'ing a component package for the Speedfox SF02 to fulfill its role as a high-performance trail bike. The standout players were its Shimano XT ICE Tech brakes and the choice of 180-millimeter rotors. Braking performance was sweet in every corner of the bike's performance envelope. We are espoused one-by supporters, but it's hard to dis' on Shimano XT, because every click shifts a gear, every shift is positive and instant, and Shimano's front mech is almost as crisp as its rear derailleur. The choice is clear: One-by? Get SRAM. Two-by? Pick Shimano. We may have come down hard on some of BMC's spec choices, but that is our job. We pushed the bike well beyond its intended role and nothing failed, which is a win in and of itself. As a complete package, the Speedfox is a turn-key trail bike that can handle challenging technical terrain - just like the sales brochure says.


Chain guide: Is this the Swiss version of putting cards in the spokes so the bicycle makes moto sounds? The BMC noise creator is clever, but unnecessary and it defeats their purchase of a Shimano clutch rear derailleur and front mech. A longer-travel, burlier bike may need a backup chain device, but not a gentleman's trail bike like the Speedfox.

Fox 32 Float fork and CTD shock: For its intended purpose, BMC chose a lightweight and proven fork and shock combination that will make a lot of customers happy for the life of the bike, but not us. If anything, 2015 marks the inevitable end of the 32-millimeter stanchion fork for serious trail and all-mountain designs.

Internal cable routing: Best we've seen in over a year.

Handlebar: Perhaps BMC made a running change, but its official spec says the Speedfox will sell with a 720-millimeter bar. Ours measured a more welcome 750 millimeters, and may have been updated, like the wider tire spec. Either way, a machine this capable should come with 760 millimeter width bars and a hack saw blade for the few who want narrow ones.

Wheels: DT Swiss calls its M1700 rims "wide." That is a pathetic statement for the world's leading wheel maker. Spline wheels are well engineered and beautifully crafted, but not the sort of stuff that is going to move the meter in the emerging long-travel trail bike category. The good news is that the Speedfox's wheelset should stand the test of time.

Saddle: Fizik has borne the brunt of many Pinkbike critiques, but the Nisene saddle on the BMC is the exception. It is reasonably comfortable for long days on the bike and its shape offers a number of useful positions for technical climbing. Sweet.



Pinkbike's Take:

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Reviews and Tech Reviews Trail Bikes Bmc Bmc Speedfox