Shimano Dura Ace C40 tubeless wheelset

Shimano rarely makes mistakes when it comes to creating high-quality components. In fact, the really great stuff often seems so commonplace that we forget to recognize it for what it is: exceptional product, meticulously designed.

The Dura-Ace C40 wheels follow that narrative: They’re excellent carbon wheels that offer plenty of stiffness without being jarringly harsh. That leaves room for personality on climbs, though pure sprinters might opt for a deeper profile rim. And boy do these all-black wheels (with subtle fades to gray) look cool.

Shimano touts these as the ideal all-rounder’s wheel. After spending a few months on them, it’s pretty clear why: the lightweight carbon rims spin up quickly (we’d guess these score pretty well in the moment of inertia tests VeloNews has performed in the past), and they felt surprisingly planted in crosswinds.

Our disc-ready test wheels feature a 40mm depth. It’s crazy to think that not long ago, this would have been an unthinkable depth for climbers, but it became easier and easier with each ride to think of these as climbing wheels. More importantly, I became increasingly confident in their stability on high-speed descents, especially coming down Lookout Mountain in Golden, Colorado, where a good gust of wind is likely to throw you off your line. The C40s tracked incredibly well and held stable in all but the biggest blusters.

Unsurprisingly, Shimano has expanded the rim width to a generous 24 millimeters internal on the disc tubeless version of the wheel. This played nice with our Hutchinson tires and allowed for lower tire pressures, thereby reducing rolling resistance.

We set them up tubeless for testing. Initial setup was basically on par with every other tubeless setup we’ve wrestled with. The tires went on easily enough, but creating a seal took some doing. That could be due to the rim, but it also could be due to the tire (we ran Hutchinson Fusion 5 tires). We don’t fault Shimano for this; the issue has more to do with wheelmakers and tiremakers creating products that often don’t work well together. Chalk this up to technology growing pains.

But once it was set up and sealed, we’ve had no air leaks since. In fact, the setup has held air better than most of our tube-and-tire setups.

Ultimately, we had trouble finding fault with these wheels. They’re everything you need in an all-around wheelset; they spin up quickly, track well in corners, remain stable in crosswinds, and offer enough give to make them comfortable in variable conditions. These complement Shimano’s already excellent Dura-Ace line of components.