Rolf Prima Ares4 Disc Rear Road WheelUnleash a devastating attack on the peloton with this Ares4 Disc Rear Road Wheel. Climb, descend, and attack sweeping bends with ease to deliver your aero edge Ares4: A Carbon ClimberThis rear disc wheel has been manufactured for climbers and those who seek every possible aerodynamic advantage. With this specific clientele in mind, Rolf Prima delivered this wheel at a lightweight 820 grams. When combined with Rolf Prima's Paired Spoke Technology for an engineering edge and their Delta Rim Technology™, this rear wheel neutralises pulling forces for a lighter and smoother roll with increased stability The XST+ Hubset is manufactured with Zero ceramic bearings for a buttery smooth ride with additional weight savings. Complete with the supreme braking prowess of a disc brake and twenty bladed CX-Ray spokes, and you have a race-ready, minimalist rear wheel that offers the complete carbon-climbing package Features:Material: Carbon (rim); CNC Machined Titanium (freehub)AerodynamicStrongLightweightResponsiveSuperb brakingIncludes rim strips, valve extenders, and QR set when applicableWeight: 820gSpecifications:Freehub: Shimano/SRAM/Campagnolo 10/11-speedHubset: XST+ with Zero Ceramic BearingsSpoke Count: 20Spoke Type: Bladed CX-RayRim Depth: 42mm Carbon ClincherRim Width: 27mm (maximum)Wheel Size: 700c Technologies:Paired Spoke Technology: Rolf Prima's Paired Spoke technology broke new ground when it was introduced in 1997. Bringing the spokes to the rim in pairs neutralises the left and right outward pulling forces, which allows them to build true wheels on lighter rims with fewer spokes. Fewer spokes and lighter rims help create increased aerodynamics and faster performing wheels Differential Flange Diameter™: Rolf Prima's patented oversize non-drive Differential Flange provides the leverage to transmit drive torque in the rear wheel to the non-drive spokes, thereby increasing the number of torque absorbing spokes Delta Rim Technology™: In skydiving, the Delta track is the fastest position for gaining forward airspeed. So, Rolf Prima mirrored this observation and adapted it for their Delta profile, which takes that cue using increased width and sidewall shaping to improve airflow and stability in straight on and crosswind situations. This wider rim is not just faster, but the additional tyre support improves cornering and handling in all riding conditions Buy Rolf Prima Wheels & Tyres from Chain Reaction Cycles, the World's Largest Online Bike Store.