Mavic’s Cosmic SLR 45 carbon wheelset is receiving a facelift — actually, a widening to be more precise. The popular road wheels increase from an almost 20mm inner width to 23mm, and from a 28mm outer to 32mm.
Another change Mavic makes is to reduce friction by 28%. How? Ceramic bearings.
Wider Mavic Cosmic SLR 45
For the 2026 Cosmic SLR 45 wheels, Mavic decided to keep the 45mm rim depth but increase the rims’ overall width. The width increase means wider tires, which create a smaller overall ground contact patch and result in less rolling resistance.
In fact, previous iterations of the Cosmic wheels wouldn’t allow for tires wider than 28mm. These new wheels can accommodate a 28mm, 30mm, or 32mm tire. Mavic’s recommendation is 30mm.
The wider rim doesn’t mean a significant loss in aerodynamic performance. Mavic designed the 2026 Cosmics with an NACA profile, spending hours testing and perfecting in the wind tunnel. The result is a smooth transition between the rim and tire, reducing turbulence and providing more stability overall. This, combined with a shorter rolling footprint (wider rims/tires), creates an efficient and smooth platform for rolling miles.
Yes, increased width means using more material, which will add to the overall weight of the wheels. While not being the absolute lightest wheels on the market, Mavic kept weights respectable with the new Cosmic SLR 45s, weighing 1480g.
Carbon Layup
Rather than having a uniform carbon thickness for wheels, Mavic uses its Adaptive Layup in building the new Cosmic SLRs. This allows Mavic to thin the material in certain areas, such as between the spokes. They then add some extra material at the spoke holes, reinforcing and adding a touch of stiffness to the wheel. The reduced mass increases performance, durability, and ride feel, all while saving up to 70g per wheel.
Spokes
Mavic uses its patented FORE Carbon process to create a stiffer and watertight rim. Rather than drilling spoke holes, threaded spoke fittings are embedded into the carbon during the layup process. Fewer holes means a stiffer rim and no need to fuss with rim tape when setting up tubeless.
The new Cosmic SLR wheels use Mavic AERO straight pull stainless steel spokes, with each wheel receiving 24. Their patented, wind tunnel-tested design creates less drag compared to flat spokes, saving up to 5 watts of power output.
Hubs
The hubs are where Mavic made another change from the previous iteration of the Cosmic SLR 45 wheels. The new wheels will still use Mavic’s Instant Drive 360 freewheel, but Mavic is now equipping them with ceramic bearings. They’ll also continue to use their Infinity Hub design, adding to the ride feel by using the same spoke length to create uniform tension across the wheel.
Mavic claims ceramic is harder than steel bearings, more durable, and reduces friction by 28%. This provides a smoother and more efficient ride overall. The Instant Drive 360 freehub offers up to 9° of engagement.
Spacing will be 12 x 100mm in front, 12 x 142mm for the rear. They are compatible with HG-R, XDR, and Campagnolo drivers and use a centerlock brake.
Mavic Cosmic SLR 45 Details
- 23mm internal width
- 32mm external width
- 28-32mm tire compatibility (30mm recommended)
- Hooked rim profile, tubeless (without tape) compatible
- Mavic AERO spokes, 24 F/R
- Infinity Hub with ceramic bearings
- Up to 9° engagement (40T)
- Weight: 1480g
- Price: $2,729
