Bike sections can vary greatly from race to race, ranging from technical singletrack to fast gravel roads. In short, you need a mountain bike that can tackle a wide swath of terrain types. For two seasons, Giant Bicycles' Athem X1 has been my solid and speedy companion. The dual-suspension bike is fast and light—pared down and stocked with new wheels my size-large bike is just 23 pounds. It climbs efficiently, cruises on flats, and it has yet to find downhill terrain on a race too tough for its mountain goat build.