The Chris King ISO Small Diameter (SD) front hub is designed for mountain bikers seeking a lightweight hub that doesn’t compromise performance. Milled from solid bar stock, the high flange diameter grants the use of shorter spokes and a wider bracing angle to increase wheel strength. Proven by professionals and chosen by privateers, our ISO SD hub puts you in the race with legendary Chris King performance. Our steel bearings, have heat-treated, surgical grade steel races that are machined simultaneously, with tools of equal wear to ensure perfectly matched inner and outer races. The quality and speed of our bearings is what sets us apart from the competition and they are what you will feel and notice on every single ride. As Chris King bearing tracks burnish they get faster with age and all our hubs and bearings are fully serviceable for years upon years of demanding use.