Wald's 742 training wheels feature three slots on the brace arm allowing this wheel set to mount on most single speed bicycles with 16- to 26-inch wheels. The brace arms are designed to fit rear frames tubes up to .75 inches in diameter. This model is intended for use by riders weighing up to 125 pounds. - The Wald Training Wheels fit 16- to 26-inch bicycles. - The Wald Training Wheels support riders up to 125 pounds.