Buying a bike for a child
Children give up on bikes that are too big and too heavy. Almost every other decision matters less than those two.
Buying a bike for a child is mostly about avoiding two mistakes: buying too big so they will grow into it, and buying something so heavy they cannot control it. Both are extremely common, and both put children off cycling.
Size by wheel diameter, not age
Adult bikes are sized by frame. Children’s bikes are sized by wheel diameter in inches. Age ranges printed on the box are marketing — children of the same age vary enormously. Measure the child instead.
| Wheel size | Approx. height | Rough age | Notes |
|---|---|---|---|
| 12in balance | 85–100cm | 2–4 | No pedals — for learning balance |
| 14in | 95–105cm | 3–5 | First pedal bike |
| 16in | 105–115cm | 4–6 | The most common first proper bike |
| 20in | 115–125cm | 6–8 | Gears start appearing here |
| 24in | 125–140cm | 8–11 | Essentially a small adult bike |
| 26in / small adult | 140cm+ | 11+ | Adult sizing from this point |
Do not buy a size up to grow into. It is the most common mistake and the most damaging. A child on an oversized bike cannot put their feet down, cannot reach the brakes properly and cannot control the bike — so they feel unsafe, and they stop wanting to ride. Buy the size that fits now.
Weight matters more than people expect
Many children’s bikes from supermarkets and general retailers weigh 11 to 14kg. A five-year-old might weigh 18kg. That is a bike approaching three quarters of the rider’s body weight — the equivalent of an adult riding a bike weighing 50kg or more.
As a rough target, look for a bike under about 40% of the child’s body weight. Lighter is genuinely transformative: they can lift it, start it, corner it and pick it up after a fall. Specialist children’s bike brands cost more and are noticeably lighter, and it is the upgrade that makes the most difference.
Balance bikes beat stabilisers
The hard part of riding a bike is balancing, not pedalling. Stabilisers let a child pedal without ever learning to balance, and often teach them to lean the wrong way in corners — which then has to be unlearned.
A balance bike has no pedals. The child sits, walks it along, and gradually starts gliding with both feet up. Most children then move to a pedal bike with no stabilisers and very little drama, often in a single session.
- Balance bikes suit children from around two, once they can walk confidently
- The saddle should be low enough to sit flat-footed
- Some pedal bikes can have their pedals and cranks removed to serve the same purpose
- If a child already has stabilisers, simply removing them and lowering the saddle usually works
The details worth checking
Brakes
- Small hands need short-reach levers — many are adjustable with a small screw
- Check the child can pull the lever hard enough to stop, while holding the bar
- Coaster brakes (pedalling backwards) are common on small bikes and confuse some children, especially those who learned on a balance bike
- A bike with hand brakes teaches a skill they will use for life
Gears
Not needed below 20in wheels, and often unhelpful — more to go wrong and more to think about. From 20in upwards, a simple single shifter with a modest range is plenty. Complexity adds cost and maintenance, not enjoyment.
Fit checks in the shop
Standover
Standing over the frame with both feet flat, there should be a small gap between the child and the top tube.
Feet down on the saddle
Sitting on the saddle, they should get the balls of both feet down. Beginners want flat feet; confident riders can sit higher.
Reach to the brakes
They must reach and squeeze the levers while holding the bar normally — not by shifting their grip.
Let them lift it
If the child cannot pick the bike up, they will not manage it at the park, in the hallway, or when it falls over.
New or second-hand?
Second-hand is excellent for children’s bikes. They are outgrown long before they are worn out, so the used market is full of bikes with plenty of life left, and a good used bike often beats a new heavy one at the same price.
- Check the frame for cracks and deep dents, especially around welds
- Spin both wheels — they should run straight and the bearings should feel smooth
- Check brakes work and pads have material left
- Surface rust on a chain is fine and cheap to replace; rust inside the frame is not
- Check the frame number against a stolen-bike register before paying
The choosing a bike guide has a full twelve-point checklist for used bikes that applies equally here.
Helmets and riding together
A helmet should sit level, roughly two finger-widths above the eyebrows, not tipped back. The straps should form a V under each ear and you should fit no more than a finger under the chin strap. Replace any helmet after an impact, even if it looks undamaged.
When they are ready for roads, the skills and safety guide covers positioning, junctions and being seen. Ride behind and slightly out from a child on the road so you shield them and can see everything they do.
Three things that decide whether they ride
Fit now, not next year
A bike bought to grow into is a bike a child feels unsafe on. That feeling is what stops them riding.
Lighter changes everything
Aim under 40% of body weight. It is the difference between a child who can manage the bike and one who fights it.
Skip the stabilisers
Balance first, pedals second. Most children make the jump in one session and never need stabilisers at all.
Questions parents ask
Balance bikes suit many children from around two, once walking is confident. Pedal bikes commonly follow between three and five. There is a wide normal range and no benefit to rushing.
No. This is the most common and most damaging mistake. An oversized bike is genuinely harder to control, and children who feel unsafe stop wanting to ride.
They work, but they are heavy, and weight is the thing that matters most for a child. If the budget allows, a lighter specialist bike or a good second-hand one is a substantially better ride.
Lower the saddle so they are flat-footed, remove the pedals or use a balance bike, and let them scoot on a gentle slope until they are gliding with feet up. Then refit the pedals. Running along holding the saddle is far less effective.
It depends on the child and the road, not the age. Judgement of speed and traffic develops gradually. Start on quiet routes and paths, ride with them, and build up.
Enough to get a light bike that fits. Buying good and selling on when outgrown often costs less overall than replacing cheap heavy bikes, since children’s bikes hold their value reasonably well.
Related guides
Three more that pair naturally with this one.
Choosing a Bike
The five bike types, frame sizing, and a 12-point checklist for buying second-hand.
Skills & Safety
Road positioning, junctions, riding in traffic, and staying visible after dark.
First 30 Days
A realistic four-week plan for getting started, and what not to worry about.
Checking a used bike?
The buying guide has a twelve-point checklist that works for adult and children’s bikes alike.