There's a lot of physics knowledge required for a seriously in depth discussion about the HED H3D FR Carbon Tubular Road Wheel, but we're not scientists, so we'll sum it up as best we can: it's damn fast. That said, it excels in fairly specific conditions, so you should be sure about how you're going to use it before you drop some fairly significant cash. By specific conditions, we mean that the H3D is best at particular speeds. If you're going to be riding consistently faster than 25mph, it'll work well as a front wheel, but if you'll be dipping below 25mph, the H3D should only be ridden in the rear. This has a lot to do with the rim depth and things called yaw angles, but you don't need to tax your wee brain trying to understand those right now. What you do need to understand is that the H3D is one of the fastest, stablest non disc wheels on the market. Its Uni woven carbon rim fabric is incredibly stiff and light, and the 90mm rim depth connects smoothly with the airfoil section spokes to manage airflow and reduce resistance. The V shaped rim is only 19mm wide, which minimizes the effects of wind when you're riding quickly and allows smooth airflow passage when you slow down. Hed also hooked the H3D up with its top secret Stability Control Technology, which is so hush hush that the company won't even say how it work, just that it helps minimize the effects of crosswinds, no matter the angle they come from. The H3D comes in both SRAMShimano and Campangolo compatible versions, and has a titanium skewer and ratchet ring to make sure it doesn't fall off in the middle of a ride.