Mavic Cosmic SL Wheels Tested (Rim Brakes)

Although the market has shifted almost entirely to disc brakes, there are still plenty of riders who use bikes with rim brakes. Whether it is personal preference, the terrain and weather encountered on rides, or a desire to stretch the budget within certain limits, the reasons for this choice are potentially numerous. Among the manufacturers that still offer wheels for this type of braking, Mavic remains a brand that aims to appeal precisely to fans of this technology, which some consider old school, with a pair of wheels full of personality: the Cosmic SL. Let’s see how they hold up after 2,500 km of riding.

Text: Olivier Dulaurent – Photos: www.3bikes.fr, Mavic

Characteristics geared toward versatility

A historic wheel maker, Mavic knows its stuff, and when it came to testing an all-round pair of wheels in a fairly attractively priced range, this is the model I was steered toward. Indeed, with a 40 mm “U”-shaped profile and a wide rim (26 mm wide externally and 19 mm internally), the results are often very satisfying because this type of wheel strikes a good balance between weight, aerodynamics, stiffness, stability and handling. Going with a deeper or shallower profile would necessarily have meant sacrificing one of these qualities. Another asset of the model, and keeping up with the times even though some brands have dropped this option, is that the Cosmic SLs are tubeless compatible. This feature improves grip and comfort in particular. For the test, however, we used tires with inner tubes. Note that Mavic recommends tires 25 to 32 mm wide, which offers a broad range for favoring either responsiveness or comfort (and grip).

Within the French brand’s wheel range, the Cosmic SL sits second in the hierarchy. At the top is the Cosmic SLR, whose higher price (€2,100 instead of €1,450) is justified by the following improvements:

• The brake caliper mount on the fork is lighter on the SLR version, saving 10 g.
• As for the spokes, they are more aerodynamic, elliptical (Mavic patent) and thinner on the SLR, for a weight saving of 100 g.
• The rim is conventional on the SL, whereas the SLR benefits from the Fore Carbon concept, saving 100 g.

The SL model tested weighs 1,617 g as measured, which is not particularly light for a 40 mm profile, but in this case, minimizing weight was not part of the brand’s specifications. That goal is left to its bigger sibling, the SLR, which hovers around 1,400 g.

Finally, and this is a real strong point that could justify the purchase on its own, both models mentioned here are covered for life and eligible for the Mavic Care program (see www.mavic.com/care), that is, crash replacement and loyalty programs, included after registering online on the brand’s website.

On the road

Before going out, mounting the tires is an unavoidable step and not always the most fun. As mentioned above, standard tubetype tires were used for the test. To be clear, whether it was a Michelin Power All Season (28 mm) up front or a Continental 5000 (25 mm) at the back, mounting them was no picnic. And that was in a comfortable setting in the garage, with the right tools and no time pressure, meaning no need to finish quickly because of cold weather or a sudden downpour. By the roadside, had rain or cold set in, there would have been plenty to complain about in the tedious job of refitting the tire. But the 2,500 km covered during the test did not result in a single puncture. Either way, the tubeless + preventive solution, which limits the risk of punctures that would force a stop by the roadside, is certainly a good way to avoid most hassles, not to mention the other supposed benefits (comfort, grip, efficiency for the best riders) linked to tubeless technology, which is widely adopted at the professional level.

From the first turns of the wheels, two characteristics stand out in particular: braking and vertical stiffness.

When it comes to slowing down, at first the brakes were not very reassuring, enough to raise doubts about future rides in the rain or even on dry mountain descents, with the pads supplied by Mavic. Fortunately, over the kilometers the whole system seemed to bed in, as if the pad–rim pairing had to wear off a layer that was too slippery, and therefore not abrasive enough, to produce the right friction coefficient and, consequently, the expected results. So everything fell into place, with very satisfying braking power, even in the rain, although of course a disc brake system remains far ahead in terms of performance.

As for vertical stiffness, it will probably surprise you. On asphalt patches and the grooves that unfortunately are increasingly common, the bike tends to “thump.” To make sure these impressions were not tied to the Specialized S-Works SL6 and Mavic Cosmic SL pairing, we also rode with a Levacon titanium frame, which is more forgiving and comfortable. The conclusion was the same: you should not choose these wheels for comfort. However, since people adapt more than expected and the test ran over several weeks, this sometimes surprising characteristic eventually faded. Lowering tire pressure by 0.5 bar was also an effective way to limit this relative discomfort.

It is also easy to imagine that the SLR, with its thinner spokes (and therefore more flex) and lighter rims, is more forgiving in this respect.

Furthermore, and this is perhaps a corollary of the pronounced vertical stiffness, lateral stiffness is top-notch, to the benefit of efficiency: nothing flexes under powerful pedal strokes, even in a sprint. This will certainly delight riders who race the federation events, especially those who fight for top spots in the final bunch sprint, or more simply, “strong-legged” riders who don’t always find in their wheels a partner that matches their power.

For a less powerful rider who prefers to spin the pedals, this stiffness will not really be a handicap, except on steeper climbs, where the wheelset’s 1,617 g combined with this stiffness is not the best partner when a 36×25 or 36×28 is needed.

In any case, this wheelset will be an excellent complement for a frame judged not stiff enough, or for the rider who wants to raise the overall stiffness of their bike. At high speed on the flat, the impression is also very good, and the inertia–aerodynamics pairing allows a sufficiently high cruising speed to be maintained without feeling like you are battling the wind.

Another advantage of the versatile 40 mm profile combined with wide rims is overall stability in crosswinds (not very noticeable in this case), or when tackling tight corners after carrying a lot of speed: there is no real need to change your habits compared with a shallower profile, nor to “force” the bike into the turn.

The overall verdict on the Mavic Cosmic SL wheels clearly shows that this is a model to be chosen with full awareness. Given their slightly high weight (though rather beneficial at high speeds thanks to inertia) and their high overall stiffness, both vertical and lateral, these wheels will shine on fairly fast courses. On the other hand, rolling climbs will pose no problems.

So riders who prioritize efficiency under pressure will be delighted, while climbers who tackle steep passes in search of a smooth, economical pedal stroke will probably turn to the SLR, about 210 g lighter and supposedly more forgiving and lively thanks to its thinner spokes, whose shape was specifically developed for that model.

=> SEE ALSO: All our Equipment articles