Review: Mavic Cosmic Carbone 40C Carbon Clinchers


Our test rig is a Parlee Z5sl with SRAM Red, except for Rival cranks to accommodate a Stages Power Meter and Rotor Q-Ring chainrings (52×36).

First, let’s get some important details out of the way. Due to limited availability of test wheels, RoadBikeReview was only able to log four rides on Mavic’s new Cosmic Carbone 40C carbon clinchers before having to return them. Thus we can only label this a short-term review.

That also means we did not get a chance to ride them in wet road conditions, which for some potential buyers will be a very important consideration. The reason being is that among several heady claims, Mavic says its new $2750 carbon hoops are far better than Zipp’s 303 Firecrest or the Reynolds 46 when it comes to wet-weather braking. In fact, during internal testing, Mavic claims the 40C’s stopped in less than half the distance, 43 meters versus 88 meters and 91 meters respectively.

Like we wrote in our initial assessment of the wheels, which you can read here, we don’t know exact protocol for those braking tests, but it’s a significant claim and one that Mavic is very proud of. (Obviously, if we get another crack at riding these wheels, we’ll do our best to (safely) test stopping distance in wet weather.)

Like all Mavic wheels, the Cosmic Carbone 40C are part of a wheel-tire system. These come with a 190-gram, dual compound 120 TPI GripLink front tire and PowerLink rear tire.

What We Did Learn

From the beginning, Mavic has been pushing these new wheels as a best-in-class performer when it comes to safety. During its product launch, the France-based wheel-and-apparel maker made a PR push to point out past instances of carbon clincher failure, and proudly beat its own drum when it came to its new wheels’ braking performance and overall safety.

Some might argue this was a subtle attempt at scare tactics. We’ll simply say that during our four test rides, the wheels performed as advertised. Dry-weather braking, even at speeds in excess of 40mph, was consistent and predictable, with no grabbing, pulsing or fading. And there were no catastrophic failures to speak of.

Each of our rides took place in the hills around Boulder, Colorado, and included significant climbing and the requisite descending, with downhill pitches of at least 8 percent, and one near-quarter-mile-long section that’s over 17 percent. Here are the four Strava files from our test rides:


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About the author: Jason Sumner

An avid cyclist, Jason Sumner has been writing about two-wheeled pursuits of all kinds since 1999. He’s covered the Tour de France, the Olympic Games, and dozens of other international cycling events. He also likes to throw himself into the fray, penning first-person accounts of cycling adventures all over the globe. Sumner, who joined the / staff in 2013, has also done extensive gear testing and is the author of the cycling guide book "75 Classic Rides: Colorado." When not writing or riding, the native Coloradoan can be found enjoying time with his wife Lisa and daughter Cora.

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  • Sandro says:

    Jason Sumner
    The Mavic Cosmic 40C is faster inertia in climb?

  • gkuch says:

    Love your photo from Mars Hill!

  • Bryan girton says:

    No catastrophic failures in four rides? I guess that would be a priority for any wheel manufacturer. $2700 for a wheelset that’s not super light or super aero and squawks when hitting the brakes? I don’t understand the aero wheel crowd, and especially how they would pay that kind of $$$ for little if any benefit over a good set of aluminums. I’ll stick with my “old skool” kysrium sl’s (tubeless) thank you, they’ve been a great wheel at a reasonable price.

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