Kreitler Rollers are known as the very best for good reason: the combination of a durable steel frame and precision-machined aluminum drums makes for a consistently smooth ride. The Kompact Alloy 3. 0 Rollers have all the features of the original Alloy Rollers in a smaller, lower profile design. The Kompact frame eliminates the extra material at the front and back of the rollers for a shorter overall length, which is easier to take along for race warm-ups and store when not in use. While the rollers will work with any style bike, the Kompact model is only compatible with wheelbases of 38 to 42in.