RockShox has announced its 2016 line-up for its higher-end forks, and the resounding trend is wider hubs front and rear. The motivation behind the new standard is to stiffen up the most common wheel sizes, which have grown, and then shrunk, over the last decade.
Fox announced last week that its new Float 27.5+ fork would be built around a 110x15mm hub standard. That move is possibly a small glimpse into the future of mountain bike suspension. Trek has already been using Boost 148 rear hubs, made in cooperation with SRAM, since last summer on its Remedy all-mountain bikes. The Boost 148 standard also allows for a more outboard chainring position, which makes space for wider suspension pivots, and opens up the bottom bracket area for increased tire clearance.
The Boost 148x12mm rear hub standard is 3mm wider on each side of the hub. The new Boost 110x15mm standard is 5mm wider on each side of the hub.
The drive behind making the hubs wider is an easy guess. Wider hubs make a stiffer wheel by giving the spokes a stronger bracing angle. RockShox claims that a 29” Boost 148 rear wheel is as stiff as a 27.5” non-boost rear wheel.
RockShox forks for Boost 110 hubs will be made in 27.5” and 29” for RockShox’s popular high-end forks — Pike, Reba, and SID. SRAM will be offering its Roam 40 wheelset in a Boost configuration, as well as XO and MTH-700 series hubsets.
The Boost 148 rear hub affects chainline by 3mm, something Trek accounted for when it co-launched the Boost 148 standard last summer. SRAM is now making Boost 148 cranksets available to public, likely knowing that other bike brands will soon be launching bikes with this same rear hub spacing.
SRAM is launching XX1 and SRAM X1 cranksets with a 3mm outset. The carbon XX1 crankset will be available in June for $472 and the aluminum X1 model is available now for $272.