Every brand of disc wheels purports that its construction is the fastest on the market. And while we won't go so far as to pick a favorite, we will tell you that the HED Stinger Disc FR wheel is among the fastest of the fast. It's faster than the HED Jet Disc by nine seconds in a 40k time trials. And while nine seconds may not seem much, the race against the clock often comes down to just a few seconds.
The Stinger is faster than the Jet for two reasons. One is that the toroidal bulge is longer. The second is that the sides of the disc where the disc meet the tire are taller. Both these features help smooth out the air flow over the tire and wheel. The result is something stunning. The Stinger disc has -90g of drag when the yaw angle is 14-degrees. Negative 90g. At 14-degrees of yaw, a conventional spoked wheel has almost 220g of drag (a 310g shift in aerodynamic drag) and even the HED Jet Disc has 30g. Compared to a conventional spoked wheel, the Stinger saves you 28 watts.
As with the Jet, the Stinger is built via a hybrid construction. The wheel begins with a 24-spoke HED Sonic hub, 24 14-gauge spokes, and a carbon-fiber 24-spoke C2 tubular rim. Once the wheel is built, two carbon fiber lenticular panels are fitted over the spoked structure. The toroidal bulges in the rim section flare out to 26mm at their widest. Once the construction is completed, you have one fast wheel that is not only extremely durable but very stiff in the lateral plane. This lateral stiffness adds to drivetrain efficiency, propelling you forward with very little energy loss.
As with all HED's C2's, this carbon-fiber rim is 23mm wide. C2 stands for the two C's that the rim is designed to minimize, Cda, or aerodynamic resistance, and Crr, or rolling resistance. The width is designed to maximize the efficiency of air passing over the tire and rim by smoothing out the air flow as well as maximize the efficiency of tires by providing better support and a better-shaped contact patch for the tire. Because of the width, you'll minimize rolling resistance and maximize aerodynamics by using 22-23mm wide tires. 19-21mm tires means a rough, bouncy ride; choosing 19-21mm tubulars is also not a great idea as not only won't they seat well, the tall sides will come perilously close to bottoming out on rough road surfaces.
When the wheel is spinning, the air will flow smoothly over the tire and across the bulged rim wall where it speeds up a bit, then moves on to the lenticular sides where it stays pretty smooth. HED has found that the lenticular sides do better in crosswinds than flat-sided discs.
The HED Stinger disc comes with a steel-shafted HED quick-release skewer and a valve extender. Any carbon-specific brake pads should work well on HED's brake track. HED says that the tried-and-true Silca disc wheel adapter fits great in the opening. The freehub body is available with Campagnolo splines or with Shimano/SRAM splines.