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While we're fans of Mavic rims and wheels, not since the days of GEL 280 and GL 330 tubular rims have they chosen to build something stunningly light. The Ksyrium line of wheels is a modern legend, but more for the great quality control and durability, not for lightness. Mavic makes no apologies for building their wheels to withstand daily abuse. Big guys and 'crossers can take any Mavic wheelset and beat them like the proverbial rented mule and the wheels will still be rolling true at the end of the day.

When the spy pictures of the Cosmic Carbone Ultimate wheels first started turning up on the web, there was speculation that they were just Lightweight brand wheels with Mavic decals. Countless all-star riders did this in the past. But not with this set. There are a number of differences. First, the rim depth. The 40mm depth is unique. Most companies either use a shallower depth, for light wheels, or greater for aero wheels. Mavic decided this was the perfect depth, shallow enough to be light, deep enough to be aero. Mavic is also unique for the aluminum rear hub body and the ability to true the rear wheel. There are tiny steel spokes at the end of the radial non-drive spokes. They're attached to spoke nipples that are attached to the hub flange. These nipples can be adjusted with a standard spoke wrench. Like Lightweight, the spokes are epoxied into place on the front flanges, and on the rear drive-side flange. This means the front wheel can't be trued, and the rear has only limited truing. With most wheels, there are spoke holes at both ends of the rim. That isn't the case with the Cosmic Carbone Ultimate; like Lightweight, the Ultimate's tire bed is smooth, no holes. This allows the carbon bed to be both lighter and stronger. It also means the rim is totally sealed from the elements. No water can be forced inside the rim, even on the wettest days.

The Ultimates weigh 1185g a set. And they're still built for the rigors of everyday riding; Mavic designed them to pass the same stress tests all other Mavic wheels undergo before being released to the public. As a friend at Mavic pointed out that they're not cyclocross wheels, but if you look through Mavic's catalogue, you'll see that they don't produce 'cross wheels, and a quick scan of the web shows there are no shortage of people running Mavic wheels in cyclocross. Their sponsored 'cross riders are already jonesing to put these wheels on their cyclocross rigs.

And they're aerodynamic to boot. Mavic's road wheels have pretty much been either about being light-ish or being aero, but never both. The Cosmic Carbone's of various iterations have always been aero, but never light. One complaint about light wheels is that they aren't stiff; these wheels might be light but they're definitely stiff. Thanks to the profiled spokes, bladed front hub flanges (the flange is sharp like an arrow rather than bulky enough to support either a j-bend or straight-pull spoke), and aero rim, the front wheel has very little drag. According to Mavic's testing, the Ultimate is a whopping 59% more aero than the heavier, shallower, more flexible Ksyrium SL.

The profiled spokes are more aero than traditional bladed spokes, more than twice as stiff as a 15 gauge spoke and weighing 35% less. By some accounts, the Cosmic Carbone Ultimate is stiffer than a standard Lightweight wheel, which is amazing since the Lightweights are 54mm deep, and these are only 40mm deep.

The Mavic Cosmic Carbone Ultimate wheelset starts with a 100% woven 12k carbon fiber rim. The rear rim is slightly asymmetric for greater strength. There are 16 spokes in the front wheel, 20 in the rear. The front wheel and the drive side of the rear are comprised of unidirectional carbon fiber spokes that extend from one side of the rim, to the hub, where they're bonded, to the other side. They're set up in a 1x pattern. The non-drive side of the rear wheel has radial unidirectional carbon fiber spokes that have a metal threaded end near the hub. These are attached to spoke nipples and can be trued with a green Park spoke wrench. The front hub shell has both a carbon fiber center section and carbon fiber flanges. The front hub runs on serviceable sealed bearings. The rear hub is made of aluminum. Both front and rear axles are made of aluminum. The rear wheel uses Mavic's QRM+ bearing system and Mavic's FTS-L cassette mechanism. The cassette is steel; Mavic doesn't believe the weight savings of titanium is significant enough to merit the extra cost. The rear axle is an aluminum monocoque design, which allows it to both lighter and stronger than their two piece axles.

Each wheel comes with a BR601 titanium-shaft quick release, and a valve extender. The front wheel comes with a spoke magnet for bike computers. The wheels also come with a complete set of Swiss Stop Yellow King Carbon pads and a bearing adjustment tool. Available for both Campagnolo and Shimano cassettes. 700c tubular only. 1185g/pair.