MAVIC COSMIC PRO CARBON SL UST – SOLID BUT UNEXCITING
The Mavic Cosmic Pro Carbon SL UST is an update of the Cosmic Pro Carbon SL C, Mavic’s first medium depth rim brake wheelset using only carbon fiber and resins in its brake track.
In going from “SL C” to “SL UST”, Mavic widened the rims, put on new hubs, and built it to their new UST tubeless standard.
The result? The new Mavic Cosmic Pro Carbon SL UST is a more comfortable, quieter, and more tubeless-ready wheelset. It’s clearly an improvement over the SL C it replaces and that I reviewed with the headline – A strong, noisy performer at a good price.
The SL UST is 2mm wider than the SL C, now 19mm across the inside of the rim (measured between the bead hooks). I could feel the added comfort in the ride. This is especially so with the Mavic Yksion Pro UST 25C tubeless tires that are included in the price of the wheels and come pre-installed. These are also better tires than Mavic supplied with the wheels before.
Compared to the much-heralded Schwalbe Pro One tubeless tires, the new Yksion rates equivalent in rolling and puncture resistance (see tubeless tire ratings here). In my experience, these tires also have a better road feel and their aerodynamics are better for this wheelset (and many others). The mounted and inflated width for the 25C tire is a mm narrower than the Schwalbe and closer to the wheels’ 25.5mm external or brake track width.
The Mavic Cosmic Pro Carbon SL UST hubset is also new but, according to the word out among shop mechanics, is a knock-off of DT Swiss 240 hubs used on many other carbon road bike wheels. Whatever the hub’s heritage, the new Mavic hub is smoother and quieter than the noise created by the SL C hubs while retaining the distinctive Mavic freewheeling sound.
This is real progress if you care about freehub buzz. We’re talking about going from it’s really annoying; don’t buy it to something like it’s acceptable if you like to hear your freewheel spin.
Mavic continues with the same version of their textured brake track on this Mavic Cosmic Pro Carbon SL UST wheelset that was used on the SL C. At the speeds I ride (18-20mph on an average training or group ride), I found it gives you good braking on dry pavement but is not very good on wet roads.
My fellow tester Nate rides considerably faster (23-26mph) and challenges wheelsets a good deal more. He was unimpressed with the braking power and heat dissipation of these wheelsets down long, steep alpine descents. We both noticed they squeal after warming up.
While these new Mavic Cosmic Pro Carbon wheels climb well enough, this kind of braking seriously dulls the reward you’ve earned from climbing when you are looking to cash in doing a long downhill. They do handle well in the crosswinds you often find in high mountain passes or those coming across open spaces.
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While they are clearly stiff when you want to turn up the speed or head up a ramp, they aren’t lively. There’s no snap and little giddy-up when you want to accelerate or get out of the saddle.
They do hold their speed well once you get moving but nothing out of the ordinary. The same can be said for their handling – solid but not inspiring aggressive riding in the corners.
Over the year or so that Mavic improved these wheels, other well-established wheel makers like Zipp, Bontrager, Roval and DT Swiss were also improving the design and performance of their hoops with new or updated wheels in this carbon clincher wheelset category popular with serious roadies. Lesser known brands and those sourcing and selling carbon bike wheels designed and made by others have also pushed further into this category at the same time.
The market price for this wheelset of around $2,100/£1,700/€2,000 puts it in a tough spot as it doesn’t match up against others in a similar price range. You can find and order it using these links to my top-ranked store Competitive Cyclist, at recommended store Planet Cyclery, and at other recommended stores at Know’s Shop.
You don’t have to spend a whole lot more to get much better performance and you can spend a lot less and get performance nearly as good. If you don’t have the budget for better performing carbon road bike wheels or if you value Mavic’s extensive dealer network and aren’t going to ride them as hard as a Group A rider like Nate, this solid wheelset will work for you.
This review appears alongside reviews of similar wheels in the post THE BEST CARBON ROAD BIKE WHEELS
First published on August 23, 2018. Date of the most recent major update shown at the top of the post.