When your riding and racing includes flats, rollers, climbs and descents, you want an aero wheel that is lightweight, responsive and has impressive rim braking. The Cosmic Pro Carbon SL UST Rear Wheel is the answer. In dropping weight to 1490 grams for the set (versus the 1650g of the non-SL version) you also get lighter hubs, better bearings, and with this rear wheel the ID360 freehub system. The carbon rim is the same and has traditionally been favored primarily for fast, rolling or flat races. This SL model delivers excellent all around performance at a lighter weight making it just as versatile on the climbs and descents. Engineered with Mavic UST technology, the 825g Cosmic Pro Carbon UST Rear Wheel offers all the benefits of tubeless, including less rolling resistance, a smoother ride quality and a reduced risk of flats. The carbon clincher/UST tubeless rims are made using the innovative iTgMax process, which not only minimizes weight, but also improves braking performance. The 40mm deep rims are NACA-compliant for low drag and excellent crosswind stability, while their lighter weight results in reduced inertia for explosive acceleration and climbing efficiency. The Cosmic Pro Carbon SL UST Rear Wheel is completed with a 25mm Yksion Pro UST tire for maximum rolling efficiency, grip and a smooth, comfortable ride making it a great option for high mileage riders, road racers, and short to middle distance triathletes who want great performance at a fair price.

The modern rim design has a 19mm internal width to complement it's 40mm profile. The key to the Cosmic Pro Carbon clincher/UST rim is the iTgMax construction process. This full-carbon construction method is promoted by Mavic as offering best-in-class durability and braking, with a much higher melting point than other carbon rims. The Integral Glass Transition Temperature system is broken out into two processes. First an inner rim bed is layered with seamless 3K carbon fiber, the contour is established without any cutting, resulting in a stronger, lighter rim with less resin, making it less susceptible to heat. The second phase creates a special rim brake track, by which a laser is used to remove the surface layer of resin in an incredibly accurate pattern all around on both side of the rim. This laser process is exceptionally precise. As resin impacted by heat more than the carbon fiber, reducing the resin reduces the risk that the rim can warp or fail. High rim temperature is the bane of any clincher or tubeless tire, which is why, for safety reasons, Mavic uses such an elaborate process, with exceptional results.

This rear wheel features a 24 hole hub, machined from aluminum, with an alloy axle, and Mavic' QRM Auto sealed cartridge bearings. The rim and hub are joined by straight pull, flat, double butted, bladed steel spokes in Mavic's distinct Isopulse lacing design. The non-drive side features a 2x pattern, while the driveside is radial to optimize the asymmetric rim for best rim dish. For the SL the spokes are laced to the rim with alloy external ABS nipples. Service is simple and straightforward and the traditional style nipples make truing efficient and quick. The lateral stiffness of the wheel is impressive while the ride quality is better than expected due to the carbon rim defeating some vibration, assisted by the steel spokes. The Pro Carbon SL carries the advanced ID360 4-pawl, 9° freehub system, which is Mavic's top drive system and super responsive at any speed.

The UST tubeless system is very effective, sealing quickly and effectively, and allowing you take full advantage of reduced friction and lower pressures which actually reduce rolling resistance and improve speed. Mavic supplies their 127 TPI casing, 700x25 Yksion Pro UST tire, which features the vaunted 11 Storm rubber compound. Fast rolling, with an inverted tread to sipe water and push out sand, the Yksion Pro UST also has inherently low rolling resistance and carries bead to bead puncture protection from a supple polymide breaker. Max pressure for the tubeless 25mm tire is 87psi, while if you equipped it with a 28mm, you'd have a 70psi max. Should you run tubes with standard clinchers, those tire sizes correspond to 102psi, and 87psi max pressure.

Of course the Cosmic Carbon Pro SL UST Rear Wheel is designed to be aerodynamic, so the combination of rim width and tire size matters. 25mm is optimal, but 28mm is not far off and some cyclists and triathletes prefer the comfort and road manners of the higher volume option. With numerous great tubeless ready tires on the market, you can certainly find the best match for your riding style, event or race, and/or road surface. Mavic provides the tubeless rim tape, tubeless valve, sealant with syringe, their BR601 titanium 130mm quick release skewer, carbon brake pads (for Shimano/SRAM holders) and a user guide. We sell the front and rear versions separately but most buy them both to run as matched pair. The weight of the paired wheelset is 1650 grams.