Mavic's new wheels are designed around ultra-stiff tubular carbon spokes that are clamped both at the rim and inside the hub. The technology essentially this minimises wheel distortion, especially when you turn on the power, and allows Mavic to shave off the weight.
The R-Sys wheelset hits the scales at just 1,335g (clinchers: 570g front, 785g rear) which is about 10 per cent less than a pair of top-end Ksyrium ES hoops. You can certainly find lighter wheels, but it's the combination of impressive weight and incredible stiffness that really scores.
The wheels accelerate fast up to speed and are lively on the climbs. Get out of the saddle and jump on the pedals and they stay tight and responsive, efficiently converting all your effort into speed on the road. Even when you're giving it everything you've got, the wheels just won't flex.
This doesn't mean that they're uncomfortable, though. Despite being laterally stiff, there's a reasonable amount of vertical compliance (aluminium spokes on the drive side at the rear add some give) so the ride isn't too harsh, even after long stints in the saddle.
The tubular carbon spokes are too wide for a standard computer magnet, so Mavic have built one in; you just slide it up and down the spoke. We haven't managed to get ours to work with a Polar system, but it speaks to all the other units we've tried without any problems.
The build quality is excellent and, although it's too early to say for sure, we expect Mavic's usual high level of durability. They're available in September in clincher and tubular versions, for around €1,100, though as yet the final price hasn't been announced.