Test Mavic Cosmic S 42 Disc wheels

With the Cosmic S 42 Disc, Mavic demonstrates that a major brand can offer a versatile and efficient carbon wheelset for less than €1000. A good way to optimize the behavior of a mid-range bike, especially since the Cosmic S are particularly reliable and easy to handle. A nice surprise on the route.

By Guillaume Judas – Photos: ©3bikes.fr

In the Mavic wheel range, the product names can sometimes differrouter novices. The name Cosmic has represented the family of aerodynamic wheels for around thirty years, with a medium or high profile. The S means the first level of the range (there are Cosmic SL and SLR at a higher level of the range), the 42 indicates the rim height, and the Disc the type of braking.

The Cosmic S 42 Disc are wheels with modern carbon rims tubeless and tubeless compatible tires, whose U-shaped profile has been studied in the wind tunnel with an internal width of 21 mm (30 mm external width) for atagand optimized tires from 25 to 32 mm section.

Unlike the high-end SLR models that benefit from nipples directly screwed into the carbon, the drilling in the rim is traditional here with classic spoke heads, which requires the use of rim tape. The rims are mounted around 24 profiled steel spokes at the front and rear, and Mavic MR801 hubs with the ID360 freewheel system. Reliable and smooth hubs with double-sealed cartridge bearings that adjust automatically when tightened, but they are not the lightest models of the brand.

Result: The wheelset weighs 1660g on the scale. (897g for the rear wheel and 763g for the front wheel), with rim tape and tubeless valves. This is 200 to 250g more (or even 300g) than high-end carbon wheels with a similar rim height, but it is not very noticeable on the terrain as we will see later because the additional weight is mainly concentrated on the hubs.

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Proven technology

The crossed spokes have an identical length at the front and rear, which facilitates maintenance and possible replacement.. At the hub level, we find the same cassette body system as on the models mounted on the wheels of the higher ranges. An advantagetage for compatibility and, again, for maintenance.

The clicking noise of the freewheel is very much attenuated, which reinforces this impression of quality and reliability from my point of view. It is however always possible to remove a rubber washer intended to attenuate this noise in the freewheel body, if you want to be noticed on descents or when crossing an urban area.

Finally, let us note that The wheels are handmade in Europe, and guaranteed for 3 years. This is in addition to a program of Crash Replacement, to benefit from a discount in the event of an accident (-50% for the first 2 years and -40% between 3 and 5 years). Additional arguments to oppose to those who would be tempted to equip themselves with little-known Asian brands, with after-sales service that is often absent or lacking.

The montagand tires, cassette (here with a Shimano HG type body, but Campagnolo ED11, N3W and XD-R type bodies are available as options) and Center Lock discs are no problem, although I should point out that for practical reasons and personal preference I opted for classic tube tires.

The spoke tension is quite high and well balanced on both sides, both front and rear.. Which obviously contributes to the overall rigidity of the Cosmic S, which are rather responsive on the ground. Throughout this test, I have not experienced any issues with wheel spin, cracking noises or freewheel body failure. The wheels support energetic and repeated accelerations with behavior consistent with that of a Tarmac SL8. I have never felt any mismatch in stiffness between the chassis and the wheels, and therefore any loss of efficiency during sharp accelerations with a high development.

In terms of comfort, I first appreciated the silent operation of the wheels, whatever the type of surface. And with 28 mm section tires (measured almost at 30 mm of actual width once mounted on the rims) inflated to 5 bar, the absorption of small vibrations and high grip in bends are there.

Measured stiffness and wind resistance

The Cosmic S 42 therefore demonstrate excellent rigidity., without being too stiff as soon as the route rises. When the need arises to stand on the pedals to overcome a difficulty, they remain easy to handle and docile, without weighing down the bike's behavior.

Their extra weight compared to my usual wheels is most apparent when lifting the bike, but I haven't climbed any hills long and steep enough to feel it in terms of performance. The few walls I had to climb were rather forceful, and in this area the Cosmic S are more than up to the task. The rims are not too heavy and do not penalize the general performance of a high-end machine.

More Their strong point lies mainly in their stability., whether on the flat at high speed and in gusts of wind, or on descents where they really inspire confidence. The 42 mm profile is a perfect compromise for a light size, with good aerodynamics while offering limited lateral wind resistance.

On the flat and with a favorable wind, I did not notice any noticeable difference in performance compared to 50 and 60 mm deep wheels, at least at a speed between 40 and 45 km/h. The rims have a higher inertia than a low profile, which helps maintain a good cruising speed.

With the wind in my face or three-quarters in my face, however, I often felt much less in grip than with higher wheels. The frequent small trajectory corrections necessary to combat the wind when it comes to bear on wheels with high rims can prove tiring in the long run, which is much less the case with the Cosmic S 42.

On the descents, I never felt any turbulence or weaving., even beyond 60 km/h when leaving an area protected from the wind by vegetation. The wheels remain perfectly stable, whether picking up speed or applying heavy braking. The shape of the rim, the width of the tire and the inflation pressure provide a lot of safety here.

A reference model

Aesthetically successful and benefiting from reliability and after-sales service reconnaked from a brand like Mavic, The Cosmic S 42 Disc are excellent wheels for those looking to upgrade a mid-range bike with basic aluminum wheels., or who are looking for a model designed to go anywhere and in all conditions.

They are not very light wheels, and they probably mark time a little in my opinion.tagor in high-level competitions compared to lighter, but also much more expensive models.

With the Cosmic S 42 Disc, Mavic nevertheless offers a reliable, reassuring product that is sufficient for most users. And whether it's in terms of pleasure or pilotage, they don't stand out at all on a bike costing over €10 either.

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