A common mistake made by parents purchasing a bike for their child is to get one that is too large so the child can "grow into it." If the frame of your child's bike is too large, she will not be able to easily control it and an accident could happen. Learning how to measure a child for a bike is a simple process and will help to ensure that your child gets a bike that will be safe to use and comfortable to ride.
Using a tape measure, measure your child's inseam. A person's inseam is measured from the inside of their crotch (where the leg meets the hip) to the ground. Write this measurement down on a piece of paper for easy reference.
Select several bikes to try at the store by looking at the height of the bike frame that is printed on the bike's description. If you are shopping for a bike for a child online, search for bikes with frames about two inches less than your child's inseam measurement.
Have your child straddle the bike so she is standing with both feet on the ground and holding the handlebars. Measure the distance between her crotch and the top of the crossbar of the bike's frame; you want at least a two-inch clearance. There is no difference in the amount of clearance you want if you are looking at a traditional boy's design bike or a one designed for a girl with a sloping front bar. If you are shopping online, you will have to rely on the difference between the listed frame size and your child's inseam measurement.
Tell your child to half sit on the bike seat, keeping one foot on the ground to balance the bike and have her hold the handlebars. Your child should be able to reach the handlebars easily, without leaning forward with more than a slight bend at the waist. If your child is bending her elbows or can reach the handlebars while sitting straight up on the seat, the bike frame is too small and will be uncomfortable to ride. Some online sites provide a measurement for the distance of the handlebars from the seat; measure that distance from your child and have them pretend to hold the handlebars to get an idea of how comfortable the frame will be.
Look at the available accessories for the bike. Some bikes, like the BMX-style ones, are designed to have frames that would be typically considered too small or uncomfortable to ride. You can purchase different length seat posts to add to the height of the bike so it will fit your child better. You can also often purchase a different style of handle bar that will bend the handles toward or away from the child so the bike is a better fit.
- Have your child wear the shoes or sneakers she will most like have on when using her bicycle when measuring her inseam; the extra inch or half-inch added by the sole of her shoes may make quite a difference in the choice of bike models you look at.