Shimano Dura Ace WH-9170-C40 Disc Tubular Wheelset

SHIMANO DURA ACE WH-9170-C40 DISC TUBULAR WHEELSET
Expanding their wheel offerings meant Shimano was bound to embrace road disc brakes. Their entries don’t disappoint.

One of the benefits of going with road disc braking is that it opens up the fork and stays to allow for wider tires. And wider tires benefit from wider rims. Shimano started with that on these wheels. The rims are 24mm wide and 37mm deep. The width makes it easier to run extra-wide tires at lower pressure, as the increased volume helps protect the rims and reduces tire deformation at the same time. That also means that, on the road at least, wider tires roll faster. When going the tubular route, the extra width not only supports the tire better, but provides more contact area for the tire to be attached to the rim.

The design sits in the sweet spot of Shimano’s wheel offerings. It’s more aero than their shallow rims, lighter than their deep rims. It balances weight and aerodynamics, so it’s home everywhere-whether that’s grinding up steep grades in your lowest gear, or taking advantage of a tailwind in your 53x11.

The rims are designed to be aero, and the fastest profile will be with tires 23-25mm wide. Because of the aero, the spoke nipples are internal. A bit harder to work on, but faster in the wind. For the same reason, the spokes are bladed. The head end is straight-pull for greater strength. Because this is a rotor-disc brake wheel, the spokes are 24 front and rear, and crossed two. This braces the wheel better when dealing with the forces that rotor braking creates.

The hubs are designed for 12mm thru-axles. They call it Road E-Thru. Even with the thru-axles, Shimano has designed the hubs the way they design their traditional quick-release axle hubs. That is, the flanges are set as wide as possible to improve lateral stiffness. This gets noticed in out-of-saddle thrashing, but it doesn’t get noticed in an important way. It improves wheel durability as it’s less likely to taco or fold in crashes.

The freehub is the same as you’ll find on quick-release hubs, with a newly-designed titanium freehub body and smoother, quieter internals.

Weight for the tubular version is 618g for the front, 771g for the rear.