Table of Contents
Our Guide
If you’re about to buy a new bike for your kid, you might be wondering how to pick the right size bike for them.
You might have even tried searching ‘how to buy the right size bike for a kid’ in which case it’s probably left you even more confused than when you started!
We’ve scoured every brand, fitting guide and all the expert advice out there to put together a simple, easy to follow guide on how to make sure you know how to pick the right size bike for your child.
We’ve also added a section on buying a BMX - as just to add a little more confusion, these are measured differently to a normal pedal bike.
How kids bikes are measured
The first thing you need to know is that kids bikes come in sizes measured by wheel diameter , as opposed to adult bikes, which are measured by frame size and seat height.
But how do you know which size wheel diameter you need for your child? Lets start with some measurements.
First things first - measurements
The first thing you need to do before we go any further is to grab:
- your child
- a hardback book
- a pencil
- a measuring tape.
We’re going to measure the following two things (and if you can, measure in inches for ease).
Height
Have your child stand barefoot against a wall. Get them to stand tall, but with feet flat and their bum against the wall. Pop the book flat on their head and make sure it’s flush against the wall.
Take a pencil and draw a dot at the bottom edge of the book.
This measurement is your child’s height (I know you know this, but just for consistency).
Inseam
Firstly - have your child pop their shoes back on - we want to measure their inseam as if they were about to ride their new bike.
Pop the book between your child legs, with the spine of the book facing towards their crotch
Raise the book until the spine firmly hits the crotch, and again the book is flush to the wall
Take the pencil and draw a dot at the top edge of the bool.
This measurement is your child’s inseam.
Finding the right wheel diameter
Now we’re going to check these three measurements along with their age using the chart below in the following order:
- Inseam
- Height
- Age
It’s very likely that your child will fall into at two of these measurements. Don’t panic, once we have the right wheel size we can do a bit more investigating using our measurements.
Checking the Standover Height
Now you’ve narrowed down the wheel measurement, you can start taking a look at the bikes you might be interested in.
The next thing we’re going to look at is in the specs of your chosen bike - and is called the Standover height.
This refers to the height of the frame, where your child will positioned if they are standing with their legs over each side of the bike.
This number needs to be at least the same as the inseam measurement of your child. The inseam height needs to be higher than the standover height - ideally a tiny bit more.
For eg: if your child’s inseam is 18”, you need to choose a bike with a standover height of 18” or less.
Any higher than this and they won’t be able to maneuver the bike.
Standover Height ≤ Inseam Measurement
Sometimes with balance bikes and bikes for younger kids, the standover height isn’t included, but instead they’ll let you know what inseam range these bikes fit.
Look for the Seatpost Height
This isn’t always as easy to find as the standover height - but if this information is included in the bike specs it might also be referred to as Seat Height.
As you might expect, this is a reference to the seat height on the lowest setting.
The best height for these depends on how experienced a bike rider you have:
New riders
If this is the first pedal bike, the rider should be able to sit on the seat and have their feet flat on the ground.
Seat height should be equal to the inseam measurement. At most it can be 1” more than the inseam measurement.
For eg: if your child’s inseam is 18”, you need to choose a bike with a seatpost height of 18-19”.
Experienced riders
Kids who have been riding a while, and know how to use the brakes, ****should be able to sit on the saddle and have their ****tip toes touch the ground.
Seat height should be 2 to 4 inches higher than the child’s inseam.
For eg: if your child’s inseam is 18”, you need to choose a bike with a seatpost height of 20-22”
Still using stabilisers?
The seatpost isn’t so important as your kid won’t be balancing the bike with their feet. Anything from 0-3” will be fine.
What if my kid is in-between bike sizes?
This is common - in fact, most kids will likely be in-between sizes.
If you have a kid that can already ride confidently - then the advice is always to take the size up.
If you’re buying a first pedal bike (even if they’re great balance bike riders) then you’re better off taking the smaller size.
BMX Bikes
If you’re buying a BMX for your child, you’ll want to work with slightly different measurements.
As BMX bikes are designed for a different type of riding, racing and performing tricks, you want your BMX to be small and fast for better control.
sizing of a BMX is based on age, height and experience - check the table below.
The advice with a BMX is to always size down if you are inbetween sizes.
Summary
If you’ve worked through the guide step by step you’ll now know exactly what size bike you need to buy for your child.
Looking for your next bike purchase? Explore open box and pre-loved bikes at KiDSiE , where we are committed to providing affordable and high-quality options for families, ensuring that every child can enjoy the thrill of riding a new bike!