Children’s bicycles are sized by the diameter of their wheels. When purchasing a bike for a toddler, the bicycle should be sized to fit the child at their current height. Buying a bike that is slightly larger can compromise safety and may increase the risk of an accident. To measure a toddler for a bike, the inseam and child’s height should be measured.
Position your toddler against a wall while he stands up tall with feet flat on the floor and heels touching the wall.
Place one end of the measuring tape in line with the floor between the feet.
Measure upward until you reach the child’s crotch. Record the measurement in inches.
Measure the child’s overall height by placing a flat object, such as a ruler, flat on top of the toddler’s head. Use a pencil to make a light mark on the wall. Measure from the floor to the mark on the wall to determine the child’s height.
Use the measurements to determine the appropriate size bike needed for the toddler. Parenthood.com notes that children with an inseam of 18 inches and an overall height of 36 to 40 inches require a bike with 12 inch wheels. Children who are 41 to 49 inches tall and have an inseam of 18 inches require a bike with 16 inch wheels. Taller children with an inseam of 23 inches and an overall height of 50 to 56 inches require a bike with 20 inch wheels.