We’re currently testing the updated version of this model called the Mavic Cosmic Pro Carbon SL UST. I expect to update this review in late July or early August 2018. Steve

The following review is part of the post BEST CARBON CLINCHER WHEELS

Despite the growth of a new, high-end wheelset market with the breakaway success of carbon clinchers since the early part of this decade, Mavic went out the back of the pack with its seeming unwillingness to offer a model to compete. The closest they came were wheels with an aluminum insert underneath the otherwise carbon rim in an attempt to absorb heat energy coming from braking.  Mavic’s view was that an all carbon wheelset wasn’t totally safe, something that most riders of first generation carbon brake tracks would agree with.

It appears that hiring some new engineering talent a couple years ago has given them an opportunity to come up with some new designs to get back in the bunch with the introduction of their first all-carbon wheelsets, the 40mm deep Mavic Cosmic Pro Carbon SL-C (clincher) for all-around riding and a 25mm Ksyrium Pro Carbon SL-C for climbing.

I had the opportunity to ride these wheels for a couple of days.  While I normally like to ride a wheelset 500-1000 miles before reviewing them, I got a good start on figuring out the character of this wheelset with the time I had and the range of conditions under which I was able to ride it.

The first ride was on a beautiful fall day covering 122 miles (196km) and 8802 feet (2682 meters) of elevation on a range of road surfaces from new, smooth pavement to packed dirt and gravel with the typical range of good to cracked but all paved road surfaces most of the ride. The climbing included a good amount of hills (<5%), moderate climbs (5-7%) and a couple 2 mile long roads to peaks, the first which averaged 12%, the second 8% and both with a few of 15-20% segments.  Of course with the distance we rode, much of the riding I did was part of a paceline on flat roads and with plenty of time solo as the group broke up and I found my nose in the wind.

The second day, as luck would have it (at least for testing purposes), I did a short recovery ride in the rain.

Mavic Cosmic Pro Carbon SL ClincherBased on this riding experience, I find the Mavic Cosmic Pro Carbon SL to be a strong all-around performer.  Its versatility is clear as it handled the range of conditions I described above equally well. The Cosmic’s dry braking is clearly its strongest feature, the performance being almost on par with the ENVE and Zipp NSW textured brake tracks on dry roads and when descending mountain pitches. On wet roads, it was notably inferior to both and more on par with the better non-textured carbon brake tracks like the Zipp Firecrest line.

The $1800/£1670/€1860 suggested retail pricing makes it attractive especially when you consider that other carbon wheelsets with similar braking performance will cost you about 1000 US dollars, Euros or Pounds more.

On the flip side, I find the noisy free-hub to be a real distraction akin to the Chris King hub volume at a slightly lower frequency. My personal preference is for a much quieter free-hub like what you get with the DT Swiss 240 but if you don’t mind or even prefer the “here I am world” sound of a freehub, this might be the wheelset for you.

Overall, the Mavic Cosmic Pro Carbon SL clincher has a very solid feel.  It is stiff when powering forward or uphill and handles and grips well on the 25C Yksion Pro tires that are sold with the wheels.

I normally test all wheels on known, low rolling resistance Continental Grand Prix 4000S II but since Mavic claims the wheels and tires are a “system” and you have to buy the tires along with the wheels, I rode them this with the tires provided.  They ride comfortably on all surfaces.  The tires measure 25.5mm inflated at the 85psi pressure I rode them at and about 26.0mm at my benchmark 100psi.  This is nearly the same width as the 25.6mm external rim width I measured halfway up the brake track and 25.8mm at the widest point, slightly diminishing their aero performance. Ideally, you want the rim width to be about 1mm wider or more than the mounted, inflated tire width so that the wind coming off the tires will re-attach to the rims with the least amount of turbulence.

Of course, I can’t test the aero performance in a wind tunnel but on the road, they feel fast but not as fast as the Zipp 303 Firecrest or Easton EC 90 SL also reviewed in my all-around post that I linked you to at the top.  I don’t know how much of their relative speed is due to this rim/tire width difference, the rim’s U-shaped aero design (usually a plus), the rolling resistance of the Yksion tires (not slick), the friction in the hub or something else.

They roll smoothly and maintain forward momentum well once getting up to aero speeds of over 18-20mph (29-32kph). They also accelerate well but nothing out of the ordinary.  As mentioned above, they felt solid climbing, if not any lighter than other all-around wheelsets.  Their measured weight of 1574 grams (well over the claimed 1450g weight) puts them at the high end of the range of wheelsets in this all-around category.

A few additional comments on braking. While I put more value on the going fast performance characteristics of wheels than the slowing down ones, several carbon wheels in this review either don’t do well slowing or shriek so much when they do or both.  Those are deal breakers for me.  Others do just fine slowing and do so quietly but don’t slow you as quickly as alloy wheels on dry roads, less quickly still on wet, and you’ve got to adopt alternate front/back braking techniques going downhill so you don’t warp them.

The latest ENVE and Zipp NSW carbon wheelsets are just as good as wheels with alloy brake tracks in the dry and wet (ENVE) and just a bit off the pace in wet (Zipp NSW) while being quiet throughout.  You can almost drag them like you do alloy wheels though I wouldn’t “poke the bear” and tempt fate.  I do it for the sake of you, my fellow road cycling enthusiast, and only after making sure my life insurance is paid up.

I’d put the Mavic Cosmic Pro Carbon SL in the mix with the ENVE and Zipp NSW in terms of dry braking performance.  I alternated the front-rear braking going down the steepest of hills (10-15%) and dragged them going down the slight less pitched ones (7.5-10%).  No heat build up, great performance in both situations though some shrieking after a while when dragging.

In the wet conditions, I found they were really no better than other non-textured tracks.  They will slow and they will stop, but you might use up all your fingers on one hand counting the seconds before they do.  I’ve read other reviewers say their experience was as good on wet roads as on dry ones.  That was clearly not what I found.

The Mavic brake track is what I would call “roughened” rather than textured like the ENVE or scalloped like the NSW. Perhaps Mavic’s doesn’t provide any place for the water to escape.  I’m also not wild about the Swiss Stop Yellow brake pads that come with these wheels and that you must use in order to prevent voiding the wheels’ warranty.  Besides leaving a yellow film on the rims, I’ve found they are more likely to squeal than other pads I’ve used on multiple carbon rims.
It’s good to see Mavic is in the all-carbon wheelset game now and, depending on the characteristics you value most, offering a well-priced option. The Mavic Cosmic Pro SL clincher aka SL-C is available at Competitive Cyclist, UK/EU Tredz 10% discount with code ITK10, Chain ReactionWiggle, stores with the best prices on this wheelset and high customer satisfaction ratings.

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  • Steve,
    First, I appreciate all of the write-ups and tests you provide to everyone that looks at the site. It’s extremely well done. I’m pretty torn regarding what direction I want to go in regarding a new wheel set-up. I’m riding a 16 TREK Emonda SL6. I weigh around 155 lbs. and ride in a hilly area. I ride three times a week, a 20 mile (1200FT), a 35 mile (2000FT) and a 50 (2500FT). I usually average around 16-17 mph riding alone. I’d rather not break the bank with a $2k set of wheels and would like to stay in the $1K-$1.5K range. With my riding style would I even see a benefit from upgraded wheels?



    • Mark, Perhaps, depends what your goals are. You aren’t riding fast enough to benefit from deeper, carbon wheels like these Mavics but if you plan to ride more and improve your speed to north of 18mph you might. As an intermediate step, you might consider a low profile alloy upgrade like those I’ve reviewed here. Will be better performers and likely more comfortable than your Bonti Race wheels. If you are interested in a higher performing all around wheelset, take a look at this review here which reviews and recommends other wheels similar in depth, material and performance to the Mavics. Steve

  • How is the ride quality compared to the mavic cosmic carbone 40 clinchers which you referenced in the intro?

  • Steve,

    Do you consider these wheels to be a significant step up from Dura-Ace C35s for all around riding? I like their price point and I am not sure I want to pay $1000 more for Zipp NSW. Being confident on descents has been quite important to me which is why I have stuck to alloy wheels (C35s and C24s) for a while.

      • Thanks for the quick reply Steve. How would you rate them in terms of comfort against C35 and C24s?. My previous experience with Mavic Ksyriums was that they were overly harsh for my 127 lb 5ft-6inch frame. By comparison to the ksyriums, the Dura-Ace wheels are a pleasure to ride (btw I ride an Aluminum CAAD10 frame, average 5000 miles a year with over 350,000 feet of climbing). I imagine the carbon on these Cosmic Pro Carbon wheelset would make these less harsh than their previous wheels, but would you say they are appropriate for a light rider like me?

        • Omar, Ksyrium are shallower, narrower alloy and these are deeper, wider carbon. Totally different wheels. They aren’t any more comfortable than the C35 or C24 but they are comfortable and would be fine for a rider of your weight. Steve

  • fernando bagnasco

    I have the choice between a set of the mavics you just reviewed or set of Easton Aero 55. Which should I get?

    • Fernando, depends on your riding profile – frequency, distance, speed, terrain, events, weight, current wheels, etc. – and what you want from a new set of wheels – more speed, comfort, climbing, racing, fondos, tubeless, etc. Tell me more and I’ll try to answer your question with more knowledge about you. Generally speaking the Easton’s are faster, true aero wheels while the Mavics are all arounders that can do more. Have you read my Easton review here? Steve

      • My apologies Steve – I should have given you more information.
        My in season race weight is 170 lbs,
        I ride 5-6 days a week with club criterium once a week and races on weekends…and they are a mix of road races and crits.
        My rides range from 60-80km durning the week up to 150km on weekends with averages of 34-37 kph The roads in Ontario Canada are pretty much flat with rolling hills and some steep pitches thrown in. No mountains here.
        I consider myself a sprinter or more of a fast finisher. I’d like a wheelset that can be both a race set and durable enough to train on too. I’d like a wheelset that gets up to speed and can maintain it but also one that can tackle the steep pitches we have here.
        I currently ride Fulcrum Quattro LG wheels on a carbon argon 18 gallium.
        I have the opportunity to pick up either wheelset for a really good deal but I don’t know which i should get.

        I came across your site just recently while looking at the Aero 55 review and I’m hooked. What a great site you have and I really enjoy reading all the reviews.
        Thanks for your quick response and I hope the information about myself gives you a clearer picture of what I’m looking for and you can give me your recommendations.

        • Fernando, Thanks. That makes my recommendation easy. From the kind of riding you do, the Easton will do more for you than the Mavics. Beyond the added speed the Aero 55s will bring, they will hold their speed far better than the Mavics. Without any really climbs, the Eastons will serve all your purposes for both training and racing far better than the Mavic. Enjoy! Steve

          • Thanks for the recommendations Steve. Since I was getting a great deal on the wheelsets, I decided to get both. I figured i will use the Mavics for my everyday riding and use the Easton wheels for races. I still have the fulcrum Quattros as back up or foul weather days.

            One last question. The Fulcrums have an aluminum alloy braking surface. Are there any concerns about using carbon specific brake pads on them.,,and what about going back to carbon afterwards. Will I risk potentially damaging the carbon braking surface after using the brake pads on non carbon wheels?


          • Whoa, that’s one way to do it. Must be one heck of a deal. How’d you swing that? (Jealous!) As to you last question, you really want to use the brake pads designed for the wheels. I don’t know what the effects would be of doing what you asked about but I don’t think it would be good for the pads. Fortunately, both of those carbon wheelsets come with the same brake Swiss Stop yellow brake pads so you don’t have to switch the pads when you switch the carbon wheel. Unfortunately, those pads make a ugly green/yellow ring on your nice black carbon tracks and the squeal pretty badly on the Eastons if they get warm. I’d ask Easton and Mavic if there any alternatives they recommend. I experimented with some ENVE pads with the Eastons and they were quieter but had different modulation. Steve

  • “Deal” is a relative term in this case 🙂
    Looks like I will be selling the Fulcrums and using mavics as my main wheels.
    I did read in your reviews about the yellow residue on the wheels from the brake pads. I’ll see how much of a pain it is.
    Thanks again.

  • Hi Steve, I love your column like everyone else. In comparing the new Mavic 40 clinchers to Enve 3.4’s you already mentioned they brake similar in the dry but the Enves are better in the wet. How about the hubs ? See any difference between the Mavic hubs and the DT Swiss 240s in terms of smoothness and rolling resistance ? Also, regarding tires you seem sold on the Continental GP 4000 II’s. Have you used the Michelin Pro 4 Service Courses ? If so, How do you compare them to the Conti’s ?

    • Stephen, The Mavic and DT240 hubs perform – roll and engage – about the same though, as noted, I found the Mavic ones very loud and the 240s are quiet. I have used the Pro 4 Service Course for a couple years and switched to the Contis for a far more comfortable ride. The Contis also have a significant amount less rolling resistance (about 6-8 watts) than the Michelin Pro 4s. Michelin’s new Power tires have replaced the Pro 4 line and the Power Competition is on par as far as rolling resistance as the Conti GP4KIIS. Steve

  • Hi Steve…
    Would you recommend the Mavic Cosmic Pro Carbon SL over the Reynolds Assault SL? They’re around the same price
    range and depth/width. The recommendation is for a long 6000 KM endurance ride – mostly flat with rolling hills, except for a few hundred kms of pure hills. I’m a light rider at 64 kg and average 26-27 km per hour over a 150 km distance. Thanks in advance!!

  • Prashant, Not sure where you are looking but through the stores I’ve found that have great prices and top customer satisfaction, the Assault SLG can normally be had for about 1/4 to 1/3rd less than the Mavic. For the kind of ride and speed you describe, I don’t think the two would perform a great deal differently. If you can get up to speeds around 30 km/hr, the Mavic would give you a bit better aero performance and maintain your speed with a little less effort. Steve

    • Thank you Steve…
      Just a related question – a few downhills on our trip can be as much as 50-90 km (although only 2 or 3 days out of 45 days ). Do you think the braking on a carbon wheel will be a problem? – overheating, noisy, etc? Also, out of curiosity…If you had an alloy wheel recommendation for the whole trip – what would that be?

  • I got a pair of cosmic carbon pro sl about 6 months ago from my local bike shop “Serious Cycling” and I like the wheels very much and ride the Santa Monica Mountains often. I recently descended Tuna Canyon for the first time and I MELTED my rear wheel. I am 6′ 4″ and 180 lbs and have been descending without any issues but this canyon is very long and steep and I had to drag the brakes more than I like to and it seems that I was a bit heavy on the rear brake. I read articles like this explaining the wonders of the brake features and improvements made in the heat management and tests conducted at iconic descents. I cannot imagine that Tuna Canyon could be more challenging on the brakes than the iconic European mountains described in multiple articles. The main difference may have been the rider 🙂 …. In any case, I took the wheel to Serious Cycling, they contacted Mavic and they replaced the wheel to which I am grateful and I am not planning on descending that Canyon again with these wheels.

  • Hi Steve,

    Can this Mavic Cosmic Pro Carbon SL C use with the Reynolds Cryo-Blue pad? I bought these wheels second handed and they come with the Cryo-Blue so I wonder if I have to buy another SwissStop Flash Pro YellowKing pad to use with these wheels as Mavic recommend?


    • Non, I’d use the recommended SwissStop. I don’t know how well the Reynolds pads will work on this textured brake track. Reynolds is kind of fussy about the pads developed for their own wheels none of which have textured tracks. Steve

  • Steve,
    I ride around 3,000 miles a year on mostly flat terrain. I weigh 178 lbs., ride an Merckx Meroux69 with disc brakes. Which would you recommend, Reynolds Assault Disc, Reynolds Aero 46 Disc or the Mavic Cosmic Pro Carbon SL Disc. I am considering ordering from Do you have any experience with this vendor. Also, what experience do you have with customs or import taxes on a set of carbon wheels. How much is the import tax if any?


    • Jeff, Of the three, I’d recommend the Assault as the best combination of performance and value for the kind of riding you describe you are doing. Take a look at my detailed recommendations on carbon disc brake wheels along with the best prices you can get them at from stores I reccommend here . Steve

  • Steve, thank you as always for the help in making these decisions. I have looked at the Cosmic Pro Carbon Exalith which is the alloy rim with a carbon Faring. Have you ridden these and if so do you have any thoughts?

  • Mat, My thoughts on these and other carbon-alloy wheels is that they are on the way out now that lighter all-carbon wheels are improving their braking performance. You really don’t see many (any?) new carbon-alloy wheels being introduced these days. Mavic claimed weight is about 200g more for the Carbon Exalith (1650g) than the Carbon SL (both without tires) and I measured SLs about 125g more than the claimed weight so the Exaliths may end up being a good deal more than the claimed weight as well. Even at the claimed weight, the Exaliths are pretty heavy as all-arounders and if you are only riding the flats, you could go 15-20mm deeper in a carbon-alloy wheel focused on just speed and pay a lot less than these. Steve

  • Steve, how would you say the Mavic Cosmic wheels compare with the Swiss Side Hadron 625 wheels?

    I’m looking for a daily riding wheel, upgrading from the OEM wheels on my bike. I ride approximately 300km a week and weigh around 120lbs.

    Thank you.

    • John, very different wheels for very different purposes. The Cosmic Pro Carbon SL Clincher is a carbon all-around for riding a wide range of terrain. The SS Hadron 625 is a heavier carbon-alloy aero wheel mostly for flat terrain ridden at high speeds in triathlons or time trials.

      Riding as much as you do, it would be best to assess what range of terrain you normally ride or plan to ride, how fast you go, how much you want to spend etc. There are several categories of wheels varying in material properties (carbon vs. alloy vs. carbon alloy), in their intended use (all-around, aero, climbing, etc.), whether they are to be used on rim or disc brake bikes and in their cost (from $500 to several thousand). I’ve done comparative reviews on wheels in most of these categories. You can find them on the homepage of the site. Steve

      • Steve thank you VERY MUCH for your quick and timely response. As an aside your website is a WEALTH of information. Thank you.

        That said I think you answered my question for me. I am looking for an all-round wheel, good in a variety of situations. The Mavic seems to fit that description. The SS Hadron 625, while a nice wheel, would only suit my needs maybe once or twice a year based on the above information.

        The roads I ride on are your average every day roads. Nothing fancy. Some hill climbs here and there too although I am not fast on my descent. I like the look of the Mavic’s and feel/think the carbon wheel will give me the most improvements. That said, I generally am not a fast rider, averaging speeds around 25 km/h. And my bike does not have disc brakes, so breaking will be rim based.

  • So these are the first pair of carbon wheels I have tried and I have to say I was impressed. I had a demo week on these wheels so I don’t own them. Personally I found the braking to be superb in the dry but during the week I had them there was no rain so I doused the wheels with about a litre of water from my bottles and I still found them to be far better than expected, of course there was no grit pick up from the roads. I will go out and say I preferred the feel of the brakes over my alloys but that is personal, the only downside is the free hub volume for me.

  • Hey Steve- I just bought these wheels. Once the OEM tires (Yksion Griplink/powerlink) wear out, what tire size do you recommend? 23 mm or 25 mm? I’ve used contis (4000sii) in the past on shallower rims and have been happy with them, but not resistant to something else. Thanks!

  • Thanks Steve. I realize different brands actually have different actual widths. I like the GP4000s. Would either 23 mm or 25 mm for that tire brand also work just as well? Presume 25C means I lose some aero advantage?

  • The GP4000 was the Conti tire I was referring too. And yes the 25C version of that tire will give up some aero benefit as it will run wider than the rim.

  • Hi Steve – Thanks a lot for your review. I’m looking to hugely upgrade from Shimano RS11s and wanted to get your opinion. I ride 3-5 times a week, 3-4 times as loops around central park (4 loops, 25 miles) and once in Jersey (40-60 miles depending on mood). Rolling hills mostly, 20-21 mph on average. Would these wheels serve my purpose the best or would you recommend another set? Thanks!

    • Dan, I don’t recommend these when compared to other all-around wheelsets. There are better ones for the same price and far better ones if you are able to spend more. Take a look at my review here of the best all-around wheels for rim brake bikes. Steve

  • Hello Steve. Thank you for the review. I intend to upgrade my Campagnolo Zonda wheelset on my Specialized Tarmac. The new wheelset will be the only wheelset that I will own so it should be an all-arounder. I’m a 64 kg cyclist. I attend GranFondos from 100 to 150kms with 1000 to 2000m elevation gain and pure climbing events 25-30kms with 2000m elevation gain. My question is which wheelset would fit me better, Mavic SL C or Zipp 302? I have opportunity to purchase Mavic SL C exc. tax at €840 and Zipp 302 at €960. When compared with the price of SL C on your review this sounds like a great bargain but Zipp 302 also sounds nice. Thanks in advance.

    • Burak, Considering only two wheelsets is quite limiting. Additionally, you should base your decision on a more comprehensive profile than you’ve presented here. I’d suggest you read this post, preparing a rider profile similar to what I’ve outlined and looking at a fuller range of options suggested by the profile that I’ve laid out in that post. Steve

  • Hi Steve. Thank you for your thorough reviews. I’m looking at upgrading my Campagnolo Zondas (15c) on my 2014 Cervelo R3, to a set of carbon all-rounders. I can get the Mavic Cosmic Pro Carbon SL C for around 1K euro, and likewise the Reynolds Assault SLs you have judged best value wheels in this category. With the Mavics at the same price, which set would you recommend?
    I’m 70 kgs and avg 6-7K kms in hilly areas a year. Avg speed 29-30 kms +. Apart from the bling effect speed is my priority, without wanting to run higher rims. Thanks.

    • Morten, Mavic, assuming you are good with the hub freewheeling sound. Also recognize that speed comes from a lot of things of which your training and position on the bike play a far bigger role than your wheels. All else being equal, tires are also important and I would change out those that come with the Mavic wheels. Steve

  • Christopher Titus

    Hi Steve,
    Thaks for the great reviews here. I was wondering if you could help me decide on wheels. I am a little overwhelmed by the options! Anyway, I was originally looking at a set of Mavic Pro Cosmic Sl C wheels at a great price but I missed my chance. So I am now comparing Reynold Assult SLG Clinchers to the Mavics. I weigh 163ish am a recreationally rider who rides a lot and averages 10-20 mph speed wise. I want to upgrade from my current Ksyriums. I like the wider rim design( of the mavics and reynolds)plus improved aero and stiffness of the wheels I’m looking at.
    There is also the newer Ksyrium carbon set which I feel are to similar in rim depth to my current wheels to be much of an upgrade.
    Any thoughts? Thank You!

    • Hi Christopher, Thanks for reading and supporting the site. Hard to recommend something based on your comment. May I suggest you take a look at this post on how to pick the right wheelset to help you navigate to what is best for your specific situation. Thanks, Steve

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