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Rim Depth: 24mm front, 25mm rear
Internal rim width: 15mm
Spoke count: 18 front; 20 rear
Deflection: 5.33mm front/ 6.94mm rear
Poor aluminum. It was once the belle of the ball, a material for high-end race bikes, and indispensable for rim manufacturers. Trust us: Life with steel rims was not that great, and Mavic deserves credit for popularizing alloy hoops. But today, carbon fiber wheels are de rigueur. So what about a humble set of wheels like Mavic’s Ksyrium Pro SL? If you pay attention to details, they might be all you need in a carbon fiber world.
It should be said, right away, that we prefer the feel of alloy brake tracks. The day may come when all road bikes have disc brakes, but for now, when we ride bikes with rim brakes, it’s confidence-inspiring to have consistent feel and power on long descents. Some carbon rims come close, but alloy always seems to perform best in our tests.
Doesn’t a metal rim weigh more than carbon? Often, that’s true, but in this case, Mavic managed to pare the Ksyrium Pro SL wheels down to a feathery 1,395 grams, essentially equal to its Pro Carbon SL C wheels. Plus, they cost $1,049 less.
The Ksyrium Pro SL wheels do have modest rim profiles, about 25mm deep, so it’s likely they don’t have the same headwind-defying properties of something like Easton’s EC90SL wheels. If you like to smash wide-open roads in the big ring, that might be a hang-up. But we like how low-profile rims behave in crosswinds.
Carbon rims are also usually applauded for stiffness. That can be true, but these alloy Mavic wheels put up some impressive numbers in our lab tests. They deflected less than both the EC90SL and Specialized’s Roval CLX40 wheels. The Ksyrium Pro SL wheels are not, however, stiffer than their carbon kin, the Ksyrium Pro Carbon SL C.
Overall, after about 1,500 miles of riding this season, we were pleased with the Ksyrium’s reliability. We’ve yet to true the wheels, and aside from the first-week break-in period, which required bearing adjustments front and rear, they were maintenance-free.
The one quibble we have is that the inner rim width is quite narrow at 15mm. That didn’t hamper our tire choice — riding 28mm-wide rubber was no problem — but generally, it seems behind the overall trend toward wider rims, which afford more tire footprint. Incidentally, we also rode Mavic’s Yksium tires on these wheels for about 600 miles, and they performed admirably — a vast improvement over some of Mavic’s previous tires.
Best of all, alloy wheels, and the Ksyrium SL Pro in particular, are usually affordable. The $1,150 price is not cheap by any means, but as an upgrade, its a fair price, considering the performance afforded by this humble wheelset.