Reynolds Blacklabel XC 259 Boost Wheelset

The Reynolds Blacklabel XC 259 Boost Wheelset is Reynolds' top-tier XC mountain wheel — a 29-inch carbon wheelset built for the demands of cross-country racing, where rotational weight costs time on a climb and a freehub that hesitates costs a position in a field sprint. The XC 259 applies the Blacklabel standard to the mountain discipline: the same manufacturing rigor and hub technology Reynolds uses for elite road and gravel wheels, translated to a 29er format with Boost spacing and a rim designed around modern XC tire sizes.

MR5 Carbon Layup and the Asymmetric Rim

The rim is built using Reynolds' MR5 (Mountain Rim 5) carbon layup — a construction method that divides the rim cross-section into five discrete zones: the spoke face, nipple bed, tire channel, hook bead, and side wall. Each zone receives a specifically selected combination of carbon fiber type, epoxy, and resin matched to the structural requirements of that area. The result is a rim where every section is independently optimized rather than produced from a single uniform layup. Reynolds certifies each batch, providing a traceable quality standard from manufacturing through delivery. The rim profile is asymmetric — spoke hole positions are shifted laterally rather than centered — which addresses a fundamental tension imbalance inherent in rear wheel construction. On a standard symmetric rim, drive-side spokes carry disproportionately higher tension to maintain proper dish, which can cause reliability issues under hard load. The asymmetric design brings spoke tension into balance across both sides. The hookless, tubeless-ready channel measures 25mm internal and 30mm external, sized for XC race and trail tires from 2.35" to 2.8". Rims arrive pre-taped for tubeless use and include valves and center lock to six-bolt adapters.

Industry Nine Hub: 120-Point Engagement

The Blacklabel XC 259 uses an Industry Nine Torch hub developed under the Reynolds program — straight pull flanges, center lock disc interface, and a 3-degree engagement, 6-pawl freehub mechanism that produces 120 distinct contact points per revolution. Three degrees of engagement means the gap between pedal input and drive engagement is functionally imperceptible. For XC racing — where riders surge constantly out of technical features, sprint flat sections, and pump rollers — that immediacy matters more than in any other mountain discipline. Freehub options cover Shimano HG (9–11 speed), Shimano Microspline (12-speed), and SRAM XD (Eagle), making the XC 259 compatible with every current XC drivetrain. Front and rear hubs run ABEC-5 sealed cartridge bearings.

Sapim CX-Ray Spokes

Both wheels are laced with Sapim CX-Ray straight pull spokes — a bladed steel design that sits at the top of Sapim's lineup and is widely used in professional race builds. The bladed profile reduces aerodynamic drag, but the more relevant benefit for wheel construction is the flat face, which prevents the spoke from twisting during tensioning. That allows a builder to achieve tighter, more consistent final tension across the wheel — which shows up in stiffness and long-term reliability. Secure Lock nipples hold tension under cycling loads. Front lacing is 2x/2x; rear is 3x/3x. Combined with the asymmetric rim and straight pull hub flanges, the result is a build with more even side-to-side tension than a conventional wheel design produces.

Build Specifications

The complete set weighs 1,380 grams — competitive at elite XC weight without the fragility trade-offs of an ultralight race-only build. Spoke count is 24 front and 28 rear. Both wheels use center lock disc brakes. Axle spacing is 15x110mm Boost front and 12x148mm Boost rear, compatible with all current Boost XC frames. At $2,299.99, the Blacklabel XC 259 sits at the top of the Reynolds mountain lineup — built for riders who race or train seriously enough for hub engagement and rim construction to make a measurable difference.