Roval 321 - Rim BrakeMaking up about 50% of your total race time, the bike portion of a triathlon is where equipment choices can make the difference between first and fifth. And no other equipment choice will save you more time than a disc wheel. While traditionally shaped disc wheels are faster than their spoked counterparts, the 321 disc turns conventional design on its head, creating the fastest wheel available. Disc wheels often fall into two categoriesa completely