Kids' bikes: which size to choose by age?

Bike size is everything

A bike that's too big scares a child (they can't touch the ground), a bike that's too small holds them back. The right bike is the one where the child feels confident and can progress naturally.

The size / age / inseam chart

Wheel size is the main criterion. Age is just a guideline — what really matters is the inseam.

How to measure inseam

This is THE measurement that determines bike size. Here's how to take it correctly:

1. The child stands upright, barefoot, back against the wall
2. Place a book between their legs, spine up, pressed firmly into the crotch
3. Measure from the floor to the top edge of the book
4. That's the inseam

Golden rule: the child must be able to place both feet flat on the ground while sitting on the saddle in its lowest position. This is the non-negotiable condition for confidence.

The balance bike: the best start

Forget training wheels (stabilizers). A balance bike teaches balance naturally, and the transition to pedals then takes just minutes. A child who has spent 6 months on a balance bike typically pedals on the first try on a 14 or 16 inch bike.

Recommended brands: Puky (LR series), Strider, Early Rider, Decathlon (B'Twin).

What really matters on a kids' bike

Weight

This is the most underestimated criterion. A 20 kg child on a 12 kg bike is like a 75 kg adult on a 45 kg bike. Absurd. A good kids' bike weighs:

• 12-14": 5-7 kg (ideal), 8-9 kg (acceptable)
• 16": 6-8 kg (ideal), 9-10 kg (acceptable)
• 20": 7-9 kg (ideal), 10-12 kg (acceptable)

Brakes

• 12-14": rear coaster brake + front hand brake (small lever)
• 16" and up: two hand brakes. Check that the child can actually pull the levers — some are too stiff for small hands.

Gears

• 12-16": single speed (no need for gears, it just adds complexity)
• 20": single speed or 6-speed depending on use
• 24": gears recommended (7-10 speed)

Brands to look for

What to avoid

• Department store bikes at €50-80: they weigh 12-14 kg in 16", the brakes are dangerous, and they break quickly
• Buying "so they'll grow into it": an oversized bike is dangerous, the child won't feel confident and won't enjoy riding
• Training wheels: they delay balance learning and create bad reflexes

When to change size?

When the child's knees come up too high (closed angle > 100 degrees) with the saddle at maximum height, it's time to move up. Generally, a bike lasts 2-3 years per size.

To find exact specs for a kids' bike or compare weights, ask L'Atelier. Our assistant knows the catalogs of the main brands.