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Road Gear

Review: Mavic Ksyrium SLR Exalith wheels

A look at Mavic's Ksyrium SLR Exalith wheels: stealthy looks, great braking, but can howl like a bee-stung toddler.

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Mavic Ksyrium SLR Exalith wheels review
The grooves can be loud, but also provide the best braking of any wheelset I've ever used. Photo: Caley Fretz © VeloNews

BOULDER, Colo. (VN) — Let’s be honest: most of us would love to roll around on carbon hoops every day, if not for the various impracticalities doing so would provoke. They’re light, sprightly, and look damn cool — the latter being more important than we’d care to admit. The problem is that carbon is ridiculously expensive to buy and replace, has a tendency to crack, and doesn’t brake particularly well. Not a solid recipe for an everyday wheelset.

Mavic has an answer for those who have come to terms with their cycling vanity, accepting their lust for things black and carbon-looking as an untenable but utterly unavoidable force of nature. They even add a nice little performance boost to the equation. It’s called Exalith, and it can be found on Mavic’s Ksyrium SLR (tested here), Comete disc, Cosmic Carbone SLR, Cosmic Carbone SLE, and R-Sys SLR.

Tech specs
The Ksyrium SLR Exalith is the lightest clincher Ksyrium ever — our set came in at 1,419 grams. The front wheel gets 18 Zircal aluminum spokes, while the rear uses 10 crossed Zircal spokes on the drive size and 10 radial Tracomp carbon spokes on the non-drive side. The rims use Mavic’s proprietary Exalith coating.

Like the K10 system introduced last year, the Ksyrium SLR is a wheel and tire system, coming packaged with Mavic’s own Yksion GripLink (front) and PowerLink (rear) tires. The set also comes with the special brake pads, wheel bags, a computer magnet, bearing adjustment tool, spoke wrench, Tracomp ring tool, and quick releases.

Exalith is a super-hard, 10-micron thick rim coating. The technology adds to the wear life of aluminum rims, and allows Mavic to machine tiny grooves into the rim itself, increasing braking friction. It also colors rims a carbon-esque anthracite black. Exalith rims require special brake pads — regular pads will be eaten alive by the hard grooved surface (as I found out, see below).

The hardness also allows Mavic to machine an additional 10g off each rim, and along with increasing brake-track life, decreases the chance of hairline cracks at the spoke outlets.

Since the Exalith is just a coating, it is possible to damage it and have the aluminum rim underneath show through. Quartz is harder, so bits of sand stuck in a brake pad can wear a groove into the coating. That said, Mavic is confident that the coating extends rim life considerably, though company officials aren’t comfortable placing exact figures on it.

“So much of wear depends on riding conditions and how the wheels are used,” explained Mavic marketing manager Zack Vestal. “Our engineers are uncomfortable making claims they can’t back up with repeatable data. But it’s a safe bet they’ll last a lot longer.”

The ride
The ride quality of Ksyriums is a known quantity — it’s always been good, and it still is. They Ksyrium SLR’s spin up nicely thanks to the light rims and are both stiff and ultra durable. They’re not the most aero (OK, maybe they’re quite literally among the least aero), but as a racing and training workhorse wheelset, they’re tough to beat. Price is higher than the regular Ksyriums, but these are better — and don’t forget all the other bits that come in the box, including tires.

The Exalith coating and machined grooves provide the best braking I’ve experienced from any wheelset, bar none. Raw power is phenomenal, and modulation is still surprisingly good. Rain has very little impact on performance. Even the first grab, when the water hasn’t been shed from the rims yet, is powerful — it’s easy to see why Garmin-Cervélo riders were snatching up Exalith wheels for rainy stages of the Tour this year.

I would go as far as to call the Exalith rims confidence inspiring. The braking is so consistent, and so powerful, that I was able to come into corners just a hair faster than I usually do. The wheels themselves helped here too: they’re stiff in the corners and the low profile rims don’t catch unexpected wind gusts. The Ksyrium SLR’s quickly became my favorite mountain wheels, equally as pleasurable going up as going down.

Though Mavic advises against it, Exalith would be fantastic for cyclocross. Wet-weather braking is key, and Exalith has the best available. The rims would undoubtedly get a bit scratched up, but the terrific stopping power would remain. For 2012, a R-Sys Exalith tubular set will be available that would fit the bill — just don’t expect to file a warranty claim when your rims don’t look pretty anymore, Mavic doesn’t condone using their wheels in such conditions. “Use them for cross at your own risk,” says Vestal.

The Yksion GripLink and PowerLink tires were actually quite impressive. I had zero flats, and they still appear to be in great shape. No cuts or holes, even in the softer front tire. The rear hasn’t even begun to flatten out yet. Ride quality is on par with other high-end clinchers like Continental’s GP4000 or the Michelin Pro3.

Now, the downside.

Mavic Ksyrium SLR Exalith wheels review
The non-drive side gets 10 Tracomp spokes, which work in compression and tension. Photo: Caley Fretz © VeloNews

Exalith has a tendency to screech like a two-year-old with a bee sting if not properly coddled, particularly in the first 300-500km of use. New (or just bad) mechanics: be advised. There is very little room for error during brake setup. The pads must be properly (even dramatically) toed in to prevent an unearthly howl. With my rear brake, even that wasn’t enough. A small amount of play was allowing one of the pads to move a bit, incurring the screech under hard braking. It wasn’t until I shimmed the pad that I was able to stop in peace.

In the first 300km (might be longer for those not descending in the mountains, hastening wear), there was literally nothing I could do to get the these wheels to shut up completely. I got rid of the horrid screech, but the wheels still produced a light whistle whenever the brakes were applied. According to Vestal, this is just a function of the brake track grooves. The peaks are sharp at first, causing the noise. Once they’ve been blunted a bit the wheels quiet down considerably.

That said, I now have a bit over 2,000km (1,242 miles) on them, and they still whistle just a bit during hard stops and light feathering (but not in between … odd).

The brake pads wore very quickly during those first 300-or-so kilometers, but the wear slowed down shortly thereafter. I’m still on my first set of pads, and wear seems to be occurring at a normal rate. I expect the pads will last at least another 500-1000km, depending on the weather, and the next pair will last much longer without that initial wear period. For testing purposes, I did one ride with brand new regular black Shimano brake pads. About 6,000 feet of descending later, they were chewed to bits. They worked fine, but simply couldn’t hold up to the hard, grooved surface.

The rims have no real noticeable wear, other than a bit of smudging. There’s certainly no bare aluminum showing through.

Mavic Ksyrium SLR Exalith
MSRP: $1,800
You get: wheels, tires, tubes, special brake pads, wheelbags, skewers, computer magnet, various tools
Pros: best braking on the market, cool looks, durable brake track
Cons: improper shoe adjustment creates sounds like small-mammal murder