Mavic Cosmic Carbone 40C Wheels

Mavic Cosmic Carbone 40C Wheels

The first time I encountered Mavic’s sealed bearings, I was Campagnolo-owning snob working in a bike shop. In short, the worst sort. Historically, this population scores high for low income, high girlfriend turnover and minds about as open as a safe deposit box.

Every now and then something is so good, so obvious in its quality, the item leaves you wondering why anyone else bothers. The way those hubs turned in my hand caused me embarrassment. I was busy telling people I was on the best stuff out there, Campagnolo. And in 1989, you could claim that without anyone arguing the point. But those hubs, they way they spun as I held them by their axles, I had to wonder why these things weren’t sporting the Campagnolo logo. And of all the companies with the power, creativity and audacity to upend the natural order to the world, how in the name of all that permits suffering could this usurper be French?

Dude, what gives?

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Since that day, I’ve eyed Mavic with alternating bouts of admiration, frustration, wonder and angst. One of my favorite wheel sets ever was a set of tubular Heliums. They were so light that switching to them meant adjusting to a bike that handled more quickly due to the reduced front wheel weight. Their electronic shifting systems were magnificent on paper, genius in the showroom and at best roulette on the open road. Their pedals have been … interesting. Heavier than a river stone and less clearance than a government intern, no amount of adjustability in their early clipless pedals could entice me to try them. Companies evolve, thank heaven.

It’s worth noting that Mavic popularized the idea of complete wheelsets, rather than hubs and rims chosen by your local wheel builder. It was an concept that carried all the mixed up feelings we have for the ex who was great in the sack but mean every other hour of the day. Complete wheels destroyed many a skill set by reducing the demand for hand-built hoops, but it also ensured that any shop on the planet could sell a first-rate, reliable set of wheels, no matter how bad their mechanics might be.

Some years back I had a chance to ride the original Cosmic Carbone wheels, and I recall how bummed I was that I wasn’t the editor who was going to pen the review. I thought they were amazing, the fastest wheel I’d ever ridden that also offered braking that didn’t frighten me. It was a potent mix. In the intervening years, every set of Mavic wheels I’ve ridden—Ksyriums and more—have proven to be reliable, ultra-true and stiff, and all of them have rolled like those hubs from ’89.

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The Cosmic Carbone 40s stand roughly at the midpoint of the Cosmic line of wheels. With a suggested retail of $2750, they enter that upper realm of carbon fiber clinchers also occupied by Zipp, Enve and Reynolds. You do get a lot for your money. A set of wheels also includes brake pads, quick releases and wheel bags, not to mention tires and tubes. They’ve got a relatively low spoke count—16 front and 20 rear—which would suggest they should be a fairly flexible set of wheels. They are, however, surprisingly stiff. Even when sprinting away from a stoplight they proved to perfectly stout for my weight. That spoke count contributes to the wheels’ overall weight, which is relatively low at 1551 grams.

I’ve encountered my share of wheels at the upper range of affordability that after a year of consistent use need bearings replaced in order to roll with the same smooth spin as when they were new. I was only able to ride these wheels for several months, and so they were rather unsurprisingly perfect when I boxed them up for their return, but my previous experience with Mavic wheels suggests these will still be rolling with the ease of one-syllable words off the tongue two years hence. Unlike many freehub bodies that I’ve encountered, when I removed the cassette lockring, the cassette slid right off; there were no deep notches in the splines, thanks to the fact that Mavic chose to use steel here to increase the wheel’s durability.

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Thankfully, Mavic went with external nipples to make these wheels easy to true. The rim construction is unusual among carbon clinchers, though. Without going full Commander Data on you, the design begins with an aluminum rim and foam around which carbon fiber is wrapped. An additional aluminum member acts as the spoke bed into which the nipples are threaded, the same as many other Mavic wheels. Mavic’s reason for this approach was to increase heat dissipation in order to keep brake response and tire pressure more consistent. I can’t say if this approach necessarily yields the intended results as I didn’t measure the wheels’ temperature at the bottom of descents, but what I can say is that unlike many other carbon clinchers, they didn’t begin to squeal under braking on long descents. Something was different for sure. I loved the fact that brake response on these rims was as smooth and consistent as with any of Mavic’s aluminum rims.

My experience on a variety of deep-V rims has taught me that not all Vs are created equal. Variations in the shape of the V will yield differences in behavior in crosswinds. My weekend rides often end with a run along the coast near LAX that results in a large helping of crosswinds. The Cosmic Carbones were reasonably well-behaved, which is to say that I didn’t have to add an additional buffer between myself and the rider ahead/next of me when riding in an echelon. However, everything I’ve learned from engineers working on frame designs (rather than wheel engineers who might have a reason to give me feedback favorable to their designs) has taught me that the longer a rim stays wide, the better the aerodynamics. In other words, the aerodynamic gains found in a wheel like the Zipp Firecrest 303 come less as a result of the the rounded spoke bed than the fact that the rim stays wide for most of its depth, which is why the deeper the rim, the faster the rim. My one knock against these wheels is that Mavic is effectively leaving cash on the table.

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On the other hand, the fact that these wheels come with a set of Yksion Pro tires (could they have found a name harder to pronounce?), which were designed for optimal leading-edge aerodynamics, Mavic is leaving less cash on the table than one might think. The Yksions (I dare you to say that three times fast) are a 127 tpi tire with slightly different designs for front and rear. The front, called GripLink, uses a lower durometer rubber for improved traction, while the rear, called PowerLink, uses a slightly higher durometer rubber for improved rolling resistance (and wear). It’s an incredibly well-thought system.

Within this class of wheels you’d be hard-pressed to find a set that offers a better combination of weight, stiffness and reliability, but you can definitely find a faster wheel. That said, I know plenty of riders who will give up some aerodynamics in exchange for the piece of mind that comes with owning Mavic. Reliability is its own value.

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7 comments

  1. backofthepack

    I’m so glad you reviewed these. I’ve only seen reviews from websites I think are a bit less than objective. I’ve been looking for carbon wheels and have been torn over which to get. The cost and weight are pretty much the same as the Zipp 303s. I have several guys in my group who ride 303s and rave about them…until we start going downhill or it gets wet. I know to give them plenty of extra room in those situations. I’m interested in your experience in wet weather braking, did they react more like aluminum or carbon rims?


    1. Author
      Padraig

      Backofthepack: Thanks for the kind words. Unfortunately, one of the benefits of living in Southern California is that I don’t have to ride in the rain much. The few times I got caught in the rain this year I just happened not to be on these wheels. My experience is that all wheels demonstrate reduced braking in wet conditions, but with new brake pad compounds, carbon clinchers aren’t nearly the death hoops they used to be, but I honestly can’t compare the braking performance in wet between the 303s and the Cosmic Carbones. My experience is that the Cosmic Carbones demonstrated smoother, more consistent braking than the 303s, but I’d rather have the 303s in a cross wind. Tough choice.

  2. randomactsofcycling

    Thanks for the review Padraig. It seems this 40mm ‘height’ of rim is the do-it-all that I am looking for. How did you find the tyres? I have a personal preference for 24mm open tubulars from Vittoria. Were these 23mm tyres?


    1. Author
      Padraig

      RandomActs: The Yksion Pros I rode are 23s and proved to be really nice tires. I’d put them up against any premium 127 tpi tire I’ve ridden. It remains true that higher thread count tires offer superior comfort and better cornering traction, though. The Yksion Pros also come in a 25mm width, but they won’t offer the same aero advantage with most wheels as the 23s do.

  3. spiff

    Mavic wheel have always been great, but I’m not sure of the rubber. 3 Garmin riders have slid out on the final turns untouched. Dan Martin in LBL, Farrar in the Giro early flat stage, and Tom Jelte Slagter in Paris-Nice(up hill)
    Just sayin.

    1. Mick

      Garmin Sharp don’t use Mavic’s tire line, Mavic only supply wheels… they source their own tires…Just sayin’

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