Review: Mavic Cosmic Carbone SLE Exalith Wheel System

Our boy Gavin spent a little over a week on our demo Mavic Cosmic Carbone SLE wheelset to help us add some dimension to our product reviews.  Gavin is the perfect guy to test wheels for us, really.  He's got the ability to really put a lot of watts through wheels, he's been riding for quite some time, and since he doesn't own the wheels we can trust that he'll be more objective.  He was also given free reign to ride them as he saw fit on whatever ride he saw fit.  Here's what he came away with:

First ride - small group ride, tempo pace mostly with one good sprint, ~35 miles. Weather: not friendly. It started pouring about 10 minutes into the ride - the kind of rain that when you're driving, you pull over because the sheets of water are pounding the windshield and you can't see anything. We rode anyway, and I figured this would surely be a good test of the Exalith braking surface and Mavic's brake pads. The braking can really only be described with one word, and that word is 'great'.  Really, just as good in a downpour as when dry.
 
At the designated sprint point, they held up well - they are just as stiff as my everyday Ksyrium ES wheels, no flexing to rub the brake pads under a 1250W effort. 
 
The only downside was a flat rear I picked up at around 25 miles. Small piece of glass I probably picked up in the gutter from all the rain runoff, unfortunately it made a fairly large cut just off center on the tire… I probably wouldn't use the GripLink and PowerLink as regular training tires, but maybe I'm just used to running one set of GP4000s for the last year and a half with no flats. Water does tend to collect in the tires as well; probably from the valve stem cutout. I did go through standing water that was deeper than the rims, so I wasn't too surprised. The only way to get the water out is to let the air out and put the tire off.

 

Second ride - solo, regular North Shore route. Seemed a bit easier to hold speed - as far as aero-ness, they're certainly better than my everyday set when rolling along at 22mph+ in a group or not. They are a bit on the heavy side, so require a bit more effort to spin up, but once you're cruising, they just want to keep rolling.

Third ride - group of 15, rotating paceline, long portions maintaining 25-27mph. Coming from non-aero wheels, the ease of holding a high pace in the group was a different feel. I did a lot of coasting and soft-pedaling when a few wheels back from the front. I did get constant comments on what the braking sounded like, from "bottle rocket" to "plane landing" so there's that.

Pros - Great braking in all conditions, black braking surface looks cool, stiff, more aero than box-section wheels
 
Cons - Braking noise is odd, a bit on the heavy side, may collect water under severe conditions

There you have it.  For $1700 you get the Exalith treatment on your Cosmic Carbone SL wheelset which turn it into the SLE.  For $1000 less than the SLR, you gain a little weight and lose the carbon spokes.  Gavin's take on Exalith mirrors mine so far, the braking performance is unparalleled.