Two ways to stop matter more at this size than at any other, because a 3 to 4 year old has the leg strength to get moving well before they have the grip strength to squeeze a lever. Back-pedaling works from day one; the hand brake waits until fingers catch up. Wheel size is matched to a 16 in to 17 in inseam and riders 31.5 in to 41.3 in tall, so feet reach the pedals at the bottom of the stroke. Training wheels bolt on until balance arrives. Welded metal rated to 143 lbs, with the chain fully covered.