Termed a pro-level climber’s shoe, the Mavic Cosmic Ultimate SL has a featherweight upper consisting of a TPU skeleton bonded to ultralight mesh, so there are no seams. It feels extremely pliable and so thin that you wonder if it’s robust enough to cope with serious cycling.
The overlapped upper design is retained by a Lycra panel to provide some structure to the flimsy tongue section, but it does make foot entry more of a challenge, and you need to smooth it all out before tightening.
While the uppers are flexible, the heel cup is solid, with upholstered pads inside to cradle the heel and prevent slip. There’s a little supporting structure at the front of the toe box too, but otherwise, the uppers just take on the shape of your foot, and are fastened by a single BOA IP1, with a single lace that crosses the opening five times before its anchor point.
The dial takes a lot of turning to tighten the shoe and usually needs more tightening as your ride progesses, because it’s hard to know when it’s finally tight, there’s so much movement in the upper. It’s not unwanted flex, as the skeleton structure prevents stretch, but the mesh panels have plenty of give.
Mavic’s Full Carbon SL sole has a 6.5mm stack height, two recessed toe vents and two lengthy vents towards the rear, plus rubber walking bumpers.
Such a light shoe — 436g in a size 45 —is best in hot weather because the ventilation breezes through it from every angle, and even by the top of hot climbs, my feet were still cool.
I didn’t feel any lack of efficiency from the light uppers, they handled every sprint and climb effort as well as the best shoes I’ve tested.
They are a shoe with quite a specific window of operation and unless you live somewhere warm, with mountains on tap, they’re hard to justify.
Mavic Cosmic Ultimate SL specifications
Upper material: TPU skeleton bonded to ultralight mesh
Outer sole: Full Carbon SL
Closure: BOA IP1
Weight (pair): 436g
Size tested: 45
Sizes available: 35–49
Price: £340 / $360