Mavic’s Cosmic series of wheels balance weight, aerodynamics and efficiency for cyclists looking to optimize their bike setup. In this review, we’ll be looking at Mavic’s mid-level Cosmic SL 40 which are one of the few wheelsets in the Cosmic lineup with a rim brake option. These wheels are also one of the few wheelsets to survive Mavic’s recent bankruptcy and are part of the brand’s plan to regain their position as a premier wheel manufacturer. Retail price on the Cosmic SL 40 is a mid-level $1,550 which includes Infinity Hub w/ Instant Drive 360 and a UST tubeless compatible design. Despite being a rim brake setup, the Cosmic has impressive braking thanks to Mavic’s patented iTgMax laser brake surface treatment.
The Mavic Cosmic SL 40 combines Mavic’s impressive iTgMax brake surface treatment and a modern 40mm depth and 19mm internal width.
| Retail Price | $1,550 (set) |
| Rating | Design: A Weight: A- Comfort: A Value: A |
| Measured Weight (in g) | 600 (front), 802 (rear) – both without valves or quick release levers |
| Likes | + Competitive pricing + Strong braking in any weather condition + Attractive exposed carbon fiber weave and versatile 40mm depth |
| Dislikes | – No extra spokes or wheel bag included – Loud braking means everyone knows when you are slowing down |
| Where to Buy (US) | Mavic |
UNBOXING
Each Mavic Cosmic SL 40 wheel comes in its own nondescript cardboard and individually packed. There was no Mavic branding on the exterior of the box to tip people off to the contents and simple cardboard inner dividers to protect each wheel. Inside the box you’ll find:
- Cosmic SL 40 wheels
- Mavic branded carbon brake pads
- Tubeless valve + tool
- Aluminum spoke tool
- Tire lever / hub tool
We were a bit disappointed to see that Mavic does not include spare spokes or wheel bags with the wheelset. Having at least a spare set of spokes would provide some peace of mind for future repairs as all shops may not have Mavic bladed spokes on hand.
FIT & FINISH
Visually, the Mavic Cosmic SL 40 has an exposed carbon fiber weave and smooth rim profile. The wheels have a 40mm depth and 26mm external depth to provide aerodynamic performance while still being easy to ride in cross winds. Surprisingly, Mavic not only offers the SL 40 in a rim brake configuration, which is becoming increasingly rare to find as most bikes transition to disc only, but also the budget Cosmic S 40 and high-performance Cosmic SLR 40 as well. Mavic does offer a variety of Cosmic wheelsets in disc setups but with different depths than 40mm. Long time Mavic fans may be disappointed by the lack of Mavic’s iconic yellow spoke or a carbon fiber hub as these wheels are nearly all-black. It’s an unfortunate downside to Mavic’s restructuring and streamlining which simplifies the number of part numbers. Instead, these wheels have a simple yellow Mavic sticker on the rim and along the hub as their only branding.
As far as the rim profile, the Mavic Cosmic SL 40 has a smooth hole-free design with a 19mm inner width. It’s a step up from the traditional 17mm inner widths of previous models but not as wide as some of the competition. That said, for most rim brake bikes you’ll be limited by frame clearance which means the 25-32mm tire compatibility will be more than enough. These wheels are also hooked and UST Tubeless compatible which means you can use them with a wide variety of tubeless or tubed setups. With the smooth inner surface there is no need for tubeless tape for tubeless setups or worrying potential sharp edges causing punctures in tubes.
One of the other notable features of these wheels are the iTgMax Brake surface which provides fast and reliable braking in any weather condition. This is Mavic’s patented technology that’s short for “integral glass transition temperature” which consists of one-piece carbon rim contour and laser treatment. It’s a technology that ensures the rim temperature stays cool while under heavy braking to optimize braking efficiency. Mavic recommends using their own carbon pads with this setup, but we suspect any well-designed carbon pad should also work. The etched surface has a slightly lighter color than the rest of the rim when you look closely, but otherwise blends in giving the wheels a disc appearance at first.
The Cosmic SL 40 wheels also have Mavic’s upgraded Infinity Hubs. These optimize power transfer by using non-contact spoke lacing and tension distribution. The wheels also use the same length spokes for both the front and rear wheels which make it simpler to source replacements and have a tool-free. Mavic has also incorporated their Instant Drive freewheel into these wheels which have a ratchet design with 40 point engagement. This design is easier to maintain with less parts and has a 9 degree engagement. That means the hub activates quickly and makes maintenance easier as the design and parts are shared across the Mavic lineup.
THE RIDE
As long time Mavic fans and owners of five sets of Ksyrium wheels we were excited to try out the Cosmic wheels for the first time. We installed the wheels onto our Specialized Tarmac SL5 with some fresh Continental 5000 tire using a tubed setup. Installing the tires was quick and easy as the inner surface is smooth and has a standard hooked setup that makes tire installation easy. While we were disappointed by the lack of a yellow spoke, one of Mavic’s most identifiable features on their wheelsets, the 40mm depth and exposed carbon weave look great and gives the wheels a pro-rider look.
Compared to the lightweight Ksyrium 125th wheelset that we normally ride with, the Cosmic SL 40 felt responsive and smooth. While the deeper profile adds a bit of weight compared to Ksyrium wheels, the Cosmic SL 40 still accelerates quickly and feels good on climbs.. At higher speeds the aero design and bladed spokes help to maintain speed and also have a satisfying sound. What impressed us most was the braking which has smooth modulation and is fade free. Mavic’s proprietary technology is a huge upgrade from the weak braking most people associate with aluminum rims and work confidently in wet or dry conditions. The performance is similar to Mavic’s Exalith aluminum wheelsets which have a textured special treatment that provides more grip and excellent wet weather performance.
As far as the hub sound, the Mavic Cosmic SL 40 has a deep tone clicking when freewheeling that amplifies to a bee hive sound when you back pedal. It’s a nice balance that’s relatively quiet yet can be loud enough when you back pedal to ensure people hear you coming. Compared to other wheels like the Bontrager Aeolus, the 9 degree engagement on the hub feels a bit dated and doesn’t feel smooth when starting to pedal after coasting. Speaking of sound, the brakes are probably the loudest part of the Cosmic wheelsets and sound like a boiling tea pot during high-speed braking. Everyone will know when your braking as the etched surface has a distinctive sound even on light braking.
THE VERDICT
Overall, we found the Mavic Cosmic SL 40 to be versatile and great looking wheels. Mavic has combined a 40mm depth with a full carbon construction to create a relatively light and aerodynamic wheelset that can excel in any conditions. The exposed carbon fiber look and depth make the wheels easy to handle in cross winds while still offering additional aerodynamic benefits at higher speeds. We were impressed with how smooth and fast the wheels felt on climbs and high-speed sprints. While the wheels lack Mavic’s iconic yellow spoke, the minimalist look and small yellow stickers result in a premium appearance. The best feature of the wheels is the braking which feature Mavic’s iTgMax surface that offer strong braking in any condition that rival disc wheelsets. As far as what could be improved, we would have liked to see wheelbags and spare spokes included with the wheels and less noisy braking. That said, if you’re looking to upgrade your rim bike setup the Mavic Cosmic offer an impressive combination of performance and versatility.
Disclaimer: The product for this review was provided by Mavic. The views expressed on this website are solely those of the authors and are here to help people make an informed choice before a purchase. The authors or the blog itself does not get any monetary compensation from the product manufacturer or third-party websites/vendor links that are posted here.