A must for BMX, recumbents and any bike with tires having an outside diameter of 22" or less. The small wheel adapter raises the level of the resistance unit of any of the Kinetic Trainers by up to three inches. By doing this, the trainers fit tires with outside diameters as small as 16". By using this adapter, Kinetic Trainers accommodate most BMX, kids and recumbent bikes. The T-580 does not work with 24" bicycles.