Three years in development, Mavic has released details of its ‘carbon clincher’ wheel – the Cosmic Carbone 40c – a wheel that they said they’d never make.

Carbon clinchers have been on the market for some years but not every manufacturer has adopted them, including Mavic – arguably the largest name in wheels – until now. Carbon clinchers are something the French manufacturer has previously said it would never make and yet this isn’t a volte-face. Let us explain…

Building a clincher wheel out of carbon is a straightforward process, you just copy the shape of an extruded aluminium box section rim. The problem is that when you go downhill and brake, you heat up the very part of the rim that is holding the tyre securely. As it heats, the carbon resin starts to become malleable and the force of the air in the inner tube is trying to push the sides apart so that the tyre comes off with obvious results.

In simple terms, to get around this carbon wheel manufacturers have to add material and/or expensive heat resistant carbon and resin, which adds weight and cost – just what you don’t want to do.

Mavic has long resisted doing this and continues to do so in its new wheel, instead they have been very clever and created a thin alloy box and built a carbon rim around it, so you get the best of both worlds. One of the proprietary keys to this is TgMax, a special carbon resin element which chemically bonds the carbon to the alloy section.

The first wheel to use this technology is the Cosmic Carbone 40c. A catchy name it’s not, but the technology inside the wheel shows that the French company has really done its homework. Below we’ve listed the wheel highlights:

– 40mm windtunnel optimized rim profile

– 1545g, 670g front and 875g rear

– 2085g, wheelset including innertubes and Mavic 190gram Yksion Pro tyres

– TgMax resin technology (Maximum Glass Transition Temperature)

– A new brake surface treatment that gives 45% improved braking in the wet using standard yellow Swiss Stop pads

– Carbon and alloy hubs previously seen on the Cosmic CXR-80 wheels

– Priced 2000 euros, UK prices are yet to be confirmed

Fore drilling with integrated nipples and alloy inserts for ease of service


  • David

    The design appears to be the worst of all worlds — the weight of an alloy rim with a carbon braking surface and a high price.

    Shopping for aero wheels last year I looked at everything available, considered all the pros and cons and opted for wheels with an alloy braking surface, similar weight and much lower price — a set like these Mavics doesn’t sit favourably anywhere in the market.

  • Jacob

    Not sure why Mavic did this. They already have a wheelset (the cosmic carbone slr) that is almost as light (it’s a 53mm rim height so actually comparable lighter) and a better breaking surface. If they were 1445g I could see the point. Am I missing something?

  • Ken Evans

    But it has a carbon braking surface not an alloy one, other firms have reinforced the rim in other ways, that are more high-tech. 2000 Euros for 1545g, isn’t competitive with some other brands.