The aero wheel landscape has been changing quite a bit in recent years. Or more accurately, the entire wheel landscape has been changing. The ascendency of disc brake systems (which we will write more about in a later article), the broad acceptance of clinchers by pros and amateurs alike, a focus on increasing rim/tire width, and careful analyses of both aerodynamics and rolling resistance have all become important topics. The result is that consumers have a broader range of choice, an easier time getting confused, but ultimately the choice of many truly fantastic products.
Today, we are taking a look at a pair of wheels that innovates in a slightly different way. The clincher wheels we have from Xtreme Carbon are traditional rim-braking carbon clinchers, and the rims are fairly unremarkable. They feature what appear to be fairly best-practices shaping for what you might call the current "Firecrest" era. That is, the rims are wide, with a blunt trailing edge that makes a decent leading edge when it rotates around and the wind is hitting it from the other side.
At 25mm wide, and around 930 grams for the front 60mm and 200 grams more for the rear 90mm Race Grade versions, there are lighter alternatives. But weight isn't what Xtreme is trying to innovate. Sure, there are some extra grams hanging around here. But what's missing is a whole lot of frontal area. When viewed from the front, the spokes are virtually invisible, thanks Xtreme's custom hubs that feature a very narrow flange spacing.
This kind of design tactic has been all but abandoned in the industry. Felt features narrow flanges on some of their in-house wheels, but that's the only example I can remember seeing in the last decade or so. Xtreme managed to fix their spokes to the hub with a cleverly designed flange that allows them to stay tucked in around 30mm more on each side than a traditional wheel. Looking at the wheels straight-on from the front or rear they appear to “float” with zero spoke visibility. This design looks a bit strange because of the difference in how the carbon hub protrudes from each side away from the oversized flange.