How do you complete the ‘Science of Speed’ equation for the new Shimano Dura-Ace & Ultegra groups? New wheels, of course! And not just any wheels, but something that Shimano considers “redefining” when it comes to their wheel offerings. Specifically, they asked themselves what was most important—speed? Aerodynamics? Rigidity? That probably depends on the type of rider and each specific use, which led to three distinct platforms.
New Profiles
Sort of like the rim brake thing, Shimano will offer their new wheels in tubular form, but most people will only see these as tubeless-ready options for the road. With a goal of reducing drag without sacrificing control, new rim profiles were developed to fit three distinct rider profiles. That includes the C36, C50, and the C60_HR or High Rigidity. For the climbers, the 36mm deep C36 is skewed towards being light weight over aerodynamics and lateral rigidity.
The C50, at 50mm deep is more of an all-around wheel with equal focus on aerodynamics, rigidity, and weight. In terms of aerodynamics, the new C50-TL outperforms the previous C60-TU by a full watt, and it offers 5.1w less drag compared to the outgoing C40-TL. Just as important though, the wheel also offers similar levels of control to the shallower C40-TL with less impact from cross winds.
Finally, the C60_HR offers +20% increased lateral rigidity for sprinting and heavier riders while also featuring low drag.
Each of the rims measure 21mm internally with a 28mm external width, and a hooked bead.
Tubeless ready, each rim comes pre-taped with a high quality tubeless valve that matches perfectly to the contour of the carbon rim. Note that the wheels include a label that advises against using tire levers. That may or may not be possible depending on the tires you choose. I started with some Vittoria Corsa tube-type tires which went onto the rim without tools fairly easily (you can still run tubes on these wheels with any tire thanks to the hooked bead).
However, the only tubeless tires I had on hand were a pair of Continental GP5000 Tubeless tires, but they were so tight that I wrestled with them to no avail. Eventually, I had to resort to one well-placed lever stroke to get the tire on the rim enough for it to seat. Long story short, it will depend on what tires you choose and your abilities, but Shimano would rather you not use a tire lever.