Losing the aluminium insert also drops the weight of the rim, now a claimed 450g for the Cosmic and 400g for the Ksyrium, and that reduced inertia should improve the responsiveness and handling across both wheelsets. The claimed weight for both wheelsets is suitably low, at 1,450g for the Cosmic Pro Carbon SL C and 1,390g for the Ksyrium Pro Carbon SL C.
Both the Ksyrium and Cosmic rims have a 17mm internal width and are 25mm wide at the brake track, and Mavic say this optimally supports a 25mm tyre, which has become the standard across the industry over the past couple of years, and the width of rubber specced on these wheels.
Speaking of which, Mavic sell their wheels as a complete Wheel Tyre System, and the tyres supplied are Mavic’s own Yksion Pro Griplink at the front, and Yksion PowerLink at the rear. The two tyres are front and rear specific, with the Griplink designed to improve front wheel cornering grip by uses a sticky compound and ‘water evacuation tread pattern, while the Powerlink focuses on lowering rolling resistance. The tyres weigh a claimed 210g a piece.
Mavic’s wind tunnel has also been put to good use, with extensive testing resulting in a new aero profile being introduced for both wheelsets. Mavic arrived at the NACA (National Advisory Committee for Aeronautics) airfoil profile after a lot of trial and error with different NACA profiles to find what produced the best results in the wind tunnel. Mavic claim the final shape offers improved stability and aerodynamic efficiency at the wind angles cyclists spend most of their time fighting.
“Across these average wind directions, we find our new wheels save watts in relation to our rivals. The new Cosmic Pro Carbon SL, for example, beats Zipp’s Z303 Firecrest 46mm rim by 2.3 watts over these yaw angles, at a range 10 degrees left-to-right,” says Brunand.
Additionally, Mavic have taken the opportunity with this second generation of carbon rim technology to use a patented laser treatment technique to improve braking performance and consistency in wet conditions, while remaining competitive with rivals in the dry.
“With the curing process we’ve developed, there is no machining, which cuts and damages the fibres,” adds Brunand. “The result is a rim surface that has almost zero variations, meaning reduced heatspots under braking and more reliable performance.
“In order to maintain this, we’ve also patented our own laser treatment – called iTGMax – for the brake track, which keeps braking consistent and free of shuddering, and maintains the carbon. For performance, it’s competitive versus our rivals in the dry, and sets new benchmarks in the wet.”
Mavic claim in the wet, the iTgMax technology reduces stopping distances by up to a third against key rivals, such as Zipp’s Firestrike and Firecrest rims – with lab tests having been carried out at Mavic’s design centre in Annecy, alongside field tests on the famous descent of Mont Ventoux.
The wheelsets all take advantage of Mavic’s alloy Instant Drive 360 hub design – a dual ratchet system introduced last year at the launch of the Pro Allroad range, engaging at just nine degrees with the scope to be compatible with any type of retention system.
The straight-pull, double-butted bladed spokes remain constructed of stainless steel for both the Cosmic and Ksyrium ranges – with the Cosmics benefitting further from Mavic’s wind tunnel work with a new tapered aero design. Each are laid out in a radial 18-spoke front and Isopulse 24-spoke rear pattern for optimum power transfer. That Isopulse pattern sees the spokes laced radially on the driveside and two-cross on the non-driveside to maximise driveside dish, thus providing a better spoke tension balance between left and right flanges.
Availability and pricing
Availability varies with each model: the new Cosmic Pro Carbon SL C goes on sale on March 15 (£1,450 RRP), while there will also be disc sibling available a month later (£1,500 RRP). A tubular version of the disc model is already available for £1,650 RRP, while the rim brake tubular version will be on sale from July 1 (£1,575 RRP).
The new Ksyrium Pro Carbon SL carbon clincher wheelset will be available from June 1 (£1,500 RRP for rim brake, £1,575 RRP for disc-specific), while rim and disc brake tubular versions are already on the market at the same price points as their Cosmic tubular siblings.
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