While not likely to be one of the most popular items in its catalogue, the increasing demand for tubular tyres among World Cup cross-country racers lead SRAM to develop an XX-level tubular carbon wheelset.
SRAM worked closely with wheel engineers at Zipp to develop its first tubular carbon wheelset for mountain bikes. While gram counting was part of the equation, SRAM mountain bike wheel product manager Bastien Donzé notes that mountain biking places significantly different demands on carbon than road riding does; as such the company chose to focus on impact resistance as well.
The tubular rims are constructed from unidirectional carbon fibre and have an external width of 25mm. The claimed weight for the XX tubular rim is 320g.
In addition to being light, the Rise XX tubular carbon rims were designed with an eye toward impact resistance
Claimed weight for the front wheel is the 15mm thru-axle version is 583g. There is also a RS-1 compatible Predictive Steering option with a 110mm-spaced front hub and 27mm oversized Torque Tube. The RS-1 compatible front hub sees 40g weight gain over the 15mm thru-axle version. (Click here to read more about RockShox' new RS-1 suspension fork.)
The rear wheel has a claimed weight of 702g.
The complete Rise XX wheelset has a claimed weight of 1,285g for the version that's compatible with traditional 15mm thru-axles.
Like the X0 hubs introduced last year, the XX wheelset uses SRAM’s Double Time freehub system, which uses four offset pawls that engage a 26-tooth ratchet ring in pairs. The result is 52 points of engagement, resulting in 6.9 degrees of engagement.
The XX hubs spin on ceramic bearings and are laced to the rims two-cross with 24 Sapim CX-Ray spokes, front and rear.
SRAM Rise XX pricing
Front Carbon Tubular (9mm QR and 15mm thru axle compatible)
Rear Carbon Tubular (standard freehub body)
Rear Carbon Tubular (XD Driver Body)
Front Carbon Tubular with Predictive Steering Interface
UK/Australia pricing to tbc. For now, SRAM will only offer the XX tubular wheelset in a 29er version. It is very likely that a 27.5in version will follow suit though.