SHIMANO DURA ACE WH-9100-C40 CLINCHER WHEELSET
In revamping the C40, Shimano has taken the all-rounder of their Dura-Ace lineup, and made it even more so. The WH-9100-C40 is lighter and faster, thanks to a rethinking of almost the entire wheel, and that goes for both the clincher and tubular versions.

The first thing is Shimano has embraced wide. Wide rims. The all-carbon tubular is 28mm wide. The aluminum/carbon hybrid clincher is 24mm wide. The width works in three ways. First the greater air volume both increases comfort and decreases rolling resistance. It also improves aerodynamics, as the transition from the tire sidewall to the rim is smoother and flatter. Both are 37mm deep and are shaped to save two watts over their predecessors. Wheel weights are 605g front, 750g rear for the tubular set, and 680g front, 847g rear for the clincher.

As should be on aero wheels, the spokes are bladed. Shimano went with exposed spoke nipples to make servicing easier. At the other end, they chose to make their hubs with wide flanges for better bracing angles. This results in greater lateral stiffness. They also designed the flanges to work with straight-pull spokes. The front wheel has radial spoking and sixteen spokes, while the rear sports a 2:1 ratio they call OPTBAL. Optimal Balance is their way of evening out spoke tension on a highly-dished hub. By having two drive spokes for every non-drive spoke, they achieve their goal. there are fourteen spokes on the right side and seven on the left.

They finish the hubs with loose-ball bearings for smoother rolling and they’ve redesigned the freehub as well. The titanium body is light and strong and covers newly-refined internals, which run quieter and smoother.

The wheels come with skewers. The all-carbon rims require Shimano’s RC55C4 pads, which are available in two widths, and need to be purchased separately. As Shimano designs the wheels as part of a system, they recommend you use these pads and only these pads, when riding their carbon-rimmed wheels. As the clincher rims feature aluminum braking surfaces, you needn’t purchase a special pad for the rims, though, naturally, Shimano prefers their own here as well.

SPECIFICATION :
Compatibility
Quick Release
Brake Type
Rim
Wheel Size
700c
Rim Depth
40mm
Rim Material
Carbon
Weight (front/rear)
605/750g
Bearing Cone/Cup
CBN Finish
Tire Type
Tubular
Spoke Count (front/rear)
16/27
QR Skewer Length (front/rear)
133/163, 168mm