Mavic’s new high-end carbon wheels (Cosmic SLR) come in three rim depths. The version with 32 mm rims is light, responsive and comfortable, and built for mountains and steep gradients. Verdict after a few hundred kilometers on the roads of the Chevreuse Valley.

By Guillaume Judas – Photos: @3bikes.fr

For 2021, Mavic is simplifying the naming of its range while readjusting the prices of its products. Cosmic is the name of all wheels with full carbon rims, with a 32, 40, 45 or 65 mm profile, for disc or rim brakes depending on the model. Ksyrium remains the low-profile aluminum wheel line, also available for both types of braking. Finally, the range level is indicated by the designations S, SL, SLR or Ultimate (the latter only available for tubulars).

The Cosmic SLR 32 Disc are therefore high-end carbon-rimmed wheels, sold at a competitive €1,850, with a verified weight of 1423 g per pair. They use rims with a 32 mm NACA profile and a 28 mm external width (21 mm internal), optimized for disc braking and for wider tires. Thanks to the UST concept and the shape of the rim bed, they are of course compatible with clincher tires and inner tubes, as well as with tubeless tires.

They differ from the Cosmic SL (€1,190) in their elliptical spokes (instead of flat ones) and in the use of the Fore Carbon concept, which features spokes that attach directly into molded metal inserts, to avoid drilling through the upper rim bridge. The rim ends up slightly lighter and, above all, no longer needs a rim strip, saving about thirty extra grams per wheel.

Note that all the brand’s carbon wheels now come with a lifetime warranty, and Mavic also offers a Crash Replacement program to buy replacement wheels after an accident, with a 50% discount if the wheels are under two years old, 40% if they are between 2 and 5 years old, and 30% if they are between 5 and 10 years old. A good way to keep customers loyal.

Simplified hubs

The entire Mavic wheel range now uses Infinity hubs, which feature automatic bearing preload adjustment and a new ID360 freehub body with a fast 9° engagement. The 17 mm (outer diameter) axle offers high stiffness, with bigger and more reliable bearings than most axles on the market. These hubs have a new spoke hole design, which optimizes spoking.

The freehub body can be removed simply by pulling it off, with no tools, which improves wheel compatibility. In addition to the traditional HG body (Shimano 9–12 speed, SRAM 10 and 11 speed), SRAM XDR (SRAM 12 speed) and Campagnolo freehub bodies are of course available as options. Note also that the axles are compatible with quick-release skewers, in addition to the now-usual thru-axle clamping, in 12×100, 12×142 or 12×135.

Like the other wheels in the disc-brake range, the Cosmic SLR 32 Disc have identical spokes at the front and rear, for more even tension. To avoid noise and wear, spokes that cross each other twice no longer touch.

An optimized tubeless technology

On these new Cosmics, Mavic has slightly modified the shape of the rim bed to make tubeless tires easier to fit. A technology that is booming, and that the French brand has believed in for several years, even though it no longer supplies tires with its wheels in the 2021 range.

Once fitted, tubeless theoretically brings many advantages, particularly in terms of efficiency and comfort, with less friction thanks to the absence of an inner tube inside the tire. Still, the system does not win unanimous support among riders, given that fitting can sometimes be tricky, the price is high, and repairs on the road can be difficult if a cut in the tire is too large to be fixed with sealant.

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Of course, the Cosmic SLR 32 Disc are also compatible with traditional tires with inner tubes, an option we favored for the wheel test, all the more enthusiastically since no rim strip is needed here. As noted above, this saves weight at the outer edge of the wheel, which has to be weighed against the competition.

Fitting Continental GP 5000 700×25 tires is a bit of a workout but manageable, thanks to the internal rim shape and its width. Mounted with lightweight butyl inner tubes (around 70 g), these tires provide a light, high-performing setup (lighter than a tubeless one) that is easy to repair at the roadside in case of a puncture.

The internal rim width (21 mm) is a perfect match for 25 or 28 mm tires, and even allows running slightly lower pressures than on a narrower rim. Thanks to the well-rounded shape of the tire in this setup, and sidewalls that continue the line of the rim section, handling stays precise, with no floaty feeling when cornering. The 25 mm tires measure a solid 28 mm in reality.

Light and dynamic

On the road, the Mavic Cosmic SLR 32 Disc immediately stand out for their zip when accelerating and changing direction. The bike feels more direct than with its original wheels. The gain in comfort compared with 19 mm rims is also noticeable, giving the impression of riding on a padded carpet where asphalt usually feels a bit rougher.

Easy to handle and well planted on the ground with the right tires, the Cosmic SLR 32 benefit fully from disc braking, for confidence and safety. And their low height makes them not very sensitive to crosswinds, although the influence of the spokes and their relative thickness should not be entirely ignored.

On steep climbs, they again add responsiveness to the bike, whether you push a bigger gear or opt for a more supple gear ratio. They make changes of pace less costly in energy than some heavier wheels, and the bike also feels more “docile” at low speeds, livelier and quicker to respond to the wide movements of the front wheel needed to get going on steep gradients. Although we did not get the chance to ride the Cosmic SLR 32 in the mountains, there is no doubt that with their light weight, comfort and handling, they would be ideal in those conditions.

The Mavic Cosmic SLR 32 Disc make changes of pace less costly in energy than some heavier wheels

On the flat, we are obviously more nuanced, although it is harder to determine precisely the aerodynamic difference with deeper wheels. They show stability and reassure in strong gusts of wind, but they lack a bit of momentum for maintaining a good cruising speed. The difference is in any case noticeable above 35 km/h with 40 or 45 mm profile wheels.

In the end, the Mavic Cosmic SLR 32 Disc are light, perfectly finished wheels that are stable and reassuring, and their hubs should not pose a problem despite intensive use. Their light weight and responsiveness are perfect for tackling hills, and they only find their limits on long training sessions on the flat. That should obviously not be the case for the other versions of the Cosmic SLR Disc, in 45 or 65 mm profile, offered at the same price, which should be chosen according to how you ride.

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