FSA achieved success
FSA's professional-level K-Force wheel features bladed spokes and aluminum nipples. All of FSA's wheels are hand built.
with its elite road bike wheel program, which spurred the Seattle-based parts maker to re-evaluate its role in the mountain bike arena. Pinkbike was recently invited to preview the first three off-road wheelsets to emerge from FSA in as many years. We use the term "off road" loosely, because FSA designed its new tubeless-ready rim profile to straddle three related, but completely different branches of cycling: cross-country mountain biking, cyclocross/gravel-riding, and road touring. Exactly how this may be possible stems from the largely ignored fact that the recent winners of the mountain bike wheel war, 29 and 27.5-inch, are exactly the same as the ancient 700c and 650b road bike dimensions - the direct descendants of the wooden-wheel pushbikes that Roman scouts used in the failed attempt to occupy the Scottish highlands.
FSA took advantage of overlapping rim sizes, and also of the rapidly growing disc-brake road bike trend, to design a tubeless-ready, 26-millimeter-width carbon rim that straddles the requirements of four distantly related customers. Surely, road touring, gravel racing, cyclocross and cross-country don’t rank highly on the to-do list of Pinkbike members, but history assures us, when a wheel maker achieves success in cross country, that it won't be long before it presses into all-mountain and gravity. That moment can't be too far away, considering that "Gravity" is the trademark of FSA's AM/DH range, so we offer this first-look piece to you as a window into the future.
Excellent construction, backed by the unparallelled experience gained from sponsoring ProTour road racing teams, suggests that FSA's wheel program will deliver the goods. That said, XC wheels are cute, but we would be far more interested in some 30-millimeter-width AM hoops.
Even spoke tension is the flag that FSA flies when describing its "dramatically" asymmetrical rim profile. The relatively narrow rim measures 25-millimeters deep, 26-millimeters outside and 21-millimeters inside the flanges. The spoke holes are drilled four millimeters off the centerline, which helps to compensate for the disparity of spoke angles required to clear a front disc brake and to offset the rear wheel's hub flanges to make room for the cassette cogs. Reportedly, the offset boosts the non-drive-side spoke tension up to 80-percent of the drive-side spokes at the rear wheel and evens the tension at the front wheel. Inside the rim, a gently curved well and locking ridges are intended to facilitate tubeless tire installation.
The hub-axle's locking collar is threaded, so owners can fine tune the bearing preload to obtain a perfectly smooth spinning wheel.
PRA (preload reduction assembly) hubs refer to the locking thread collar of FSA's hub-axle that allows owners to adjust the preload of the bearings to perfection. The hub's straight-pull flange design facilitates higher spoke tension and a longer life for the wheel. FSA's claim is that the higher tension and the degree of integrity that its offset rim brings to the table allows a lower spoke count, so the hubs have only 24 holes. FSA's hub has a six-bolt rotor flange and its freehub interface supports SRAM and Shimano cassettes and also SRAM HD drivers. Axles offered are conventional quick release, and 15 QR front or 142 by 12-millimeter rear axles. Two bearing options are featured: ceramic hybrids for FSA's top-line K-Force; and stainless steel for its SL-K and Afterburner models.
The Freehub Ratchet
No modern wheel maker dare enter the fray without a unique story about their freehub ratchet mechanism. FSA's "Quick Draw" freehub uses six pawls and a 27-tooth ratchet ring. The pawls are arranged in two sets of three, with one trio out of sync. The result is 54 points of engagement, which works out to a minimal, 6.6-degree engagement angle. Because three pawls are always locked into the ratchet ring at any given time, the freehub should hold up to a lot of torque and abuse.
A look through the middle of the K-Force front wheel reveals the offset spoke drilling of the carbon rim, and the hub's straight-pull spoke flanges.
FSA wheel are hand built in their Taiwan factory. Like all of its high-end components, FSA offers its new wheel at three price points: the 1414-gram pro-level K-Force, followed by the 1450-gram SL-K wheelsets both feature its new carbon rim, while the 1590-gram Afterburner model uses an aluminum version of the same rim profile. All the wheels use a 24-spoke, cross two lacing pattern and all are shipped with either a Stan's or an FSA tubeless kit. The wheels are tensioned up to 120 kilograms, which is reportedly 20 to 40 kg higher than average. K-Force wheels are built up with bladed stainless steel spokes and aluminum nipples, while the other models use butted stainless spokes and brass nipples. FSA says that its wheels are not weight limited and they come with a one-year warranty and a crash replacement policy. Presently, FSA will handle all warranty and repairs from its Mukilteo, Washington, facility, but they plan on adding service centers at prominent distributor locations. FSA offers all models in 29 and 27.5-inch sizes, and prices range from $2049 to $649 USD.Full Speed Ahead