Shimano has four 11-speed Dura-Ace wheel models now, each named for their rim height. BikeRadar recently received a test set of the C50 wheels, which Shimano is positioning directly opposite Zipp's 303. Shimano claims that the C50 is more aero than the 303, although the company declined to give out test data.
Shimano said the C50 is faster than the 303 between 0 and 15 degrees of yaw, but the 303 is faster at yaw angles above 17 degrees. Zipp wasn't immediately able to respond to BikeRadar's request for their perspective. We will add that information when we have it, and we hope to get both wheelsets into a wind tunnel.
In keeping with the current wider-is-better trend, the C series wheels have a wider, 23mm rim (designed to work with 25mm tires) and a wide spoke bed (for stability in crosswinds).
In a notable departure from the carbon clincher trend, however, Shimano is holding the line on metal brake tracks for its C24, C35 and C50 clinchers. Each of those wheels feature a carbon cap co-molded to an aluminum tire bed.
"With carbon clinchers, if you look at the total weight of what we’re able to do with aluminum extrusion, there is very little additional weight savings to using all carbon, but the price goes up dramatically," Shimano vice president Wayne Stetina said. "If you could save another 30-40g, but the price goes up $1,000 and you lose the aluminum braking surface, what’s the point?"
Built for 11-speed, the C50 wheels are compatible with 9- and 10-speed cassettes, too
The C50 clinchers weigh 1,672g and cost $2,200/£1,445. The Zipp 303s, by contrast, weigh 1,520g and cost $3,350/£2,199.
These new C series wheels, with bladed spokes and new rim shapes, represent Shimano's first fully committed effort towards aero wheels. While the C24 and C35 models have external spoke nipples, the C50s hide the nipples inside the rim.
Check back soon for a review of the C50 clinchers after we have some miles on them.
Shimano is also introducing a 30-day guarantee on all its new road wheels. Customers who buy them and decide they don't like them can return the wheels for a full refund, or trade them for another model.
Check back soon for a full review after we have some more miles on the C50s