Almost any deeper section carbon wheel rim you can think of nowadays adopts a bulbous U-shape, which is claimed to increase stability in crosswinds. That wasn’t always the case; seven or eight years ago, a V-shaped rim profile was prevalent.
Reynolds has been one of the few brands to continue to use the V-shaped profile though, on its top-spec Blacklabel Aero rims, although its less pricey rims have adopted a U-shaped profile.
