Right Bike Size for Kids – Guide

A properly fitting bike allows a comfortable and safe sitting position for children as well as teenagers. The size of a child’s bike is usually based on the wheel diameter.

In adults, this is based on the frame size or seat tube length.

Proper bike fit allows the muscles can deliver optimal strength. This is less tiring and avoids overloading the knees.

How to size a kids/youth bike

Because children have less experience and balance, they are more susceptible to falls.

However, the habit of cycling is taught at a young age, and a seat tailored to a child’s height ensures optimum comfort and encourages them to ride on their bicycle.

All the while teaching them how to ride more intuitively. So how does one choose the right size of a child’s bicycle? Here is a table for a general rule.

Age	Body Length	Bike Size
2-4 year	87-103 cm	12 inch
3-6 year	96-117 cm	14 inch
5-7 year	110-123 cm	16 inch
6-9 year	117-135 cm	18 inch
7-10 year	123-140 cm	20 inch
8-11 year	129-146 cm	22 inch
10-14 year	140-164 cm	24 inch
> 13 year	160-176 cm	26 inch

Here is a graphic that describes the size of kids better. (I do not own the rights to this graphic, credit goes to http://www.wiggle.co.uk/)

Case 2: Size Based on Inseam and Height (More Advanced)

The size chart for children is based on age and height. Since not every child is equally tall at a certain age, it is better to choose the bike size based on body length.

A study [1] in which young children between 7 and 14 years show that choosing a bike just based on the bike size is not the proper way.

Along with the bike size, the most influential parameter for a sitting position is the inseam.

Kids Bike Size Chart

This is significantly different for children even of the same height. Based on the body size of 1,400 youth, one arrives at a conclusion summarized in the following table, which takes into account the growth:

Body Length	Inseam	Bike Size
120-140 cm	< 52 cm	16 inch
	52-74 cm	20 inch
	> 74 cm	24 inch
141-160 cm	< 62 cm	20 inch
	62-80 cm	24 inch
	> 80 cm	26 inch
> 160 cm	< 74 cm	24 inch
	>74 cm	26 inch

The study was conducted with over 1400 young folks. 9 body measurements were taken, which in the end determined the size of the bike.

With these data, one could find out which size fits the children for anybody’s length. The only thing you need to adjust is the seat and handlebars.

A criterion of good seat height is the distance between the pedal and the saddle, corresponding to 88.3% percent of the inseam. Children between 120 cm and 140 cm tall fit so almost on a 20-inch bike.

For children between 140 cm and 160 cm, the average bike size is 24 inches. For teens bigger than 160 cm, the best fitting bike would be a bike with a wheel size of 26 inches.

Although most would prefer to go for the standard and easy to use first case, some like to go beyond paying close attention to detail and choosing the bike that would perfectly suit them.

This would require more hard work, but it would make your purchase all the more enjoyable in the end. You can always check out the comprehensive study referenced below for more information.

Kids Bike Sizes: How To Choose The Right Children’s Bicycle

Reference

[1] Laios L, Giannatsis I. 2010 Ergonomic evaluation and redesign of children bicycles based on anthropometric data. Appl Ergon 41: 428 – 435.