Making a bike grow with your child

Riding a bike can be a life-long pleasure, especially if you start your experience as a young child. There is nothing more contagious than the thrilling laughter of your child as he or she has learned to ride solo – no parents – no trainer wheels – with the wind in their hair and the road to freedom ahead.
To help make their future bike rides as much fun as the first, it is important that the bike is fitted to them for comfort and safety. Fitting an adult comfortably on a bicycle while not easy is at least a one or two time adventure; fitting a child on a bike is much harder because their bodies are constantly changing. This article covers how to do it with kids in the 5-12 age range.

Getting Started

First you need a bicycle frame with wheels that fit your child. That may seem obvious, but choosing too big or too small a frame is a common error adults make. Bring your child and try frames out because some kids are bigger or smaller than the norm. There are some other important points about choosing a frame that can affect the life of the bike for that child. I highly recommend that you make sure the stem – the post with the handle bars that fit into the frame - is angle adjustable; this will allow you to adjust it out as your child grows. The seat post should also be adjustable. Then make sure the saddle rails are long. Moving the saddle back will allow a frame to accommodate a taller child, because it increases the distance to the pedals. Hence, it will grow with them for longer. Adults always prefer smaller frames if they can be made to fit properly. This is doubly so for kids since smaller frames are lighter and easier for them to control. Keeping a small frame with longer seat post, stem, and saddle rails can keep a small frame usable for much, much longer.

From a Kid’s Perspective

It is important to let your child have a say in the selection of the bike once you have determined the right size. If they don’t think the bike makes them look “cool,” they likely won’t ride it when you get it home.

Size Makes a Difference

When we talk about the size of the bike for children we are really referring to the wheel size not necessarily the frame size because the proportions of the frame with a kid’s bike is determined by the wheel size. While kid’s wheel sizes are measured in 12, 16, 20, and 24 inches we will concentrate on the 20 and 24 inch sizes.

We recommend that you determine the size of bike for your child in two ways.

First, you can use a chart.


Age Height


Wheel size

5-11 yrs old 4'-4'8"



11+ yrs old 4'9"+



Second, you should have your child test drive the bike.

A chart is a good place to start but if your child doesn’t look comfortable on the bike you need to rethink your choice. They should be in close to an upright posture. Their knees should not be touching the handlebars. Their legs should be at about a 30o angle when the peddle is at the lowest extended position not stretched out. There should be no difficulty in them turning the handlebars left or right.

Safety is in the Eyes of the Beholder

Buying a bike for your child that is too big with the idea that he or she will grow into it is a big mistake. For safety reasons your child should be able to put a foot on the ground while on the seat without leaning the bike very far.

Please only use the above information as a guideline since each child is different.

©2018 Dr. Yan Lyansky