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:
- Ride 1 – Super Flagstaff: 20 miles, 3,000 feet of climbing, 41mph top speed
- Ride 2 – NCAR Hill Repeats: 15 miles, 2,000 feet of climbing, 42mph top speed
- Ride 3 – Double Flagstaff: 19 miles, 2,500 feet of climbing, 38mph top speed
- Ride 4 – Sunshine Canyon: 23 miles, 2,700 feet of climbing, 41mph top speed