Kids' bikes by age and height

1Kids' bikes go by wheel size

Adult bikes are sold by frame size. Kids' bikes are sold by wheel size, from 12" up to 26". On CrankMart you can filter kids' bikes by 12", 16", 20", 24" and 26" wheels.

2Measure first, then use age as a rough guide

Children grow at different rates, so height and inseam tell you more than age. Giant's kids' sizing guide says choosing by age alone is not recommended, and suggests measuring inseam (K2).

How to measure inseam (the method in Giant's guide, K2):

1. Your child stands with their back to a wall, feet about shoulder-width apart, in the shoes they'll ride in.
2. Slide a thick book between their legs, spine up, and raise it gently as if it were a saddle.
3. Mark the top of the spine on the wall.
4. Measure from the floor to the mark.

Measure height against the same wall.

3Two example size charts

4Fits now beats "room to grow"

It's tempting to buy a size up. Both makers advise against it: Trek says not to size up thinking they'll grow into it, because a bike that's too big can slow learning and knock confidence (K1), and Giant suggests choosing one that fits today (K2). The good news: a well-kept kids' bike is easy to pass on or sell on CrankMart when it's outgrown.

5How a kids' bike should fit (from Trek's guide, K1)

• Seat height: for balance bikes and a first bike without training wheels, feet flat on the ground while seated. For bikes with training wheels and more confident riders, toes touching the ground.
• Standover: your child can stand over the bike with feet on the ground and a little gap above the top tube.
• Feet on the pedals: the ball of the foot rests on the pedal.

6Brakes, gears and extras

Trek's guide (K1) suggests:

• Brakes: start with no brakes (balance bikes) or a coaster brake (pedal backwards to stop), then hand brakes once hands are stronger. Some bikes have both.
• Gears: one gear to start. Add gears as skills and hand strength grow.
• Training wheels: a good option for kids too big for a balance bike or who want more time to build confidence.
• Accessories: definitely a helmet, plus front and rear lights on every ride.

7Buying a used kids' bike

Kids' bikes are great second-hand buys. A quick look-over:

• Wheel size matches your child's height and inseam on a maker's chart.
• Brakes stop the wheel when squeezed (or when pedalling backwards on a coaster brake).
• Wheels spin straight; tyres have tread and hold air.
• Chain runs smoothly; on geared bikes, every gear works.
• Seat post goes up high enough for growing legs, and the clamp tightens.
• Training wheels or extras you'd like are included, or easy to add.
• Run the frame serial through our free serial check (crankmart.com/au/community/check).
• Bring your child along to sit on it, if you can.

FAQ