Balance bikes and the first pedal bike
A balance bike is simply a small bike with no pedals. Children push along with their feet, learn to glide, and pick up the instinct for steering and leaning into corners before they ever have to worry about pedalling. Balance bikes are cheap to buy used, hold up to plenty of abuse, and are the single best investment a parent can make for getting a young child riding well. Most children who ride a balance bike from two years old are riding a pedal bike without stabilisers by four.
The first pedal bike, usually a 14 or 16 inch wheel, should be as light as you can reasonably afford. A cheap supermarket bike at this size weighs close to the child riding it, which makes learning to pedal uphill or turn a frustration. A lightweight alloy bike from Frog, Isla, Hoy, Squish, or the better Specialized, Trek or Giant kids ranges weighs half as much and the difference is enormous for small legs.
Training wheels have gone out of fashion for good reason. A child who rides a balance bike does not need them. If the bike you are buying comes with stabilisers fitted, you can usually remove them and find that the child rides without them inside an afternoon.
Buying used, where the savings really are
The best value in kids' bikes is buying used from parents whose child has outgrown a bike that was barely ridden. A decent child's bike typically gets used intensely for one to two years before the child grows out of it. Frames are usually in excellent condition. Components may need a quick service but nothing is usually worn out.
Look for bikes from the specialist kids' brands first. Frog, Islabikes, Hoy Bonaly, Squish and Early Rider are all designed around child ergonomics, with narrow Q factors, properly sized brake levers that small fingers can actually reach, and gearing that works on small hills. These bikes hold their value exceptionally well on the used market, which means you can often buy them, use them for a year or two, and sell them on for nearly what you paid.
Supermarket bikes and no-name imports are best avoided. They are usually too heavy, the components fail quickly, and they are sized for an average child who does not exist. The resale value is also zero.
Fit matters more on a kids' bike than on any other type
Children grow at different rates. A seven year old can comfortably fit on anything from a 20 inch to a 24 inch wheel depending on their leg length. Always check the standover height before you buy. The child should be able to straddle the top tube with both feet flat on the floor and an inch of clearance to spare.
Seat height should allow the child to touch the ground with their toes when seated. For a new rider still building confidence, set the seat low enough that both feet can be flat on the ground. For a more confident child, raise it so the leg is almost straight at the bottom of the pedal stroke. Pedalling efficiency matters once the child is beyond the basics.
Brake lever reach is the detail most often overlooked. Small hands cannot pull a brake lever designed for adults. If the child cannot comfortably wrap their fingers around the lever and pull it firmly, they cannot stop the bike. Quality kids' brands adjust the lever reach properly. Supermarket bikes almost never do.
Checking a used kids' bike
The single most important check is the bottom bracket. Kids' bikes often live outdoors, get left in the rain, and the bottom bracket is the component that suffers first. Hold each pedal and try to wiggle it. Any movement means the bottom bracket is past its best. On many kids' bikes it is a sealed cartridge and easy to replace for ten to twenty pounds in parts.
Check the tyres for cracking and perishing. Kids' bike tyres often do not wear out through mileage. They age. Rubber goes hard, the sidewalls crack, and grip disappears. A set of new tyres on a 20 inch wheel is thirty or forty pounds, which is usually worth paying for.
Inspect the frame at the welds. Look closely around the bottom bracket shell and the seat tube. A dropped bike or a bike that has been slept on can crack at these points, and on aluminium it is often not repairable.
Finally, squeeze the brake levers all the way to the bar and back. They should return cleanly. Sticky levers usually mean corroded cables, which is a cheap and quick fix.
Brands to know and what each one is worth
Frog Bikes are the leading British brand for kids' bikes. Lightweight aluminium frames, proper sized components, good geometry. Prices on the used market are strong because demand is high. A three year old Frog 55 in good condition still sells for over sixty percent of its new price.
Islabikes stopped producing bikes in 2023 but the existing stock remains on the used market and is still highly prized. They were the original specialist kids' bike brand and the engineering is excellent. Prices can be eye-watering on eBay but fairer on Cyclesite and similar.
Hoy, Squish and Early Rider are the other respected UK kids' brands. All three make lightweight, well thought-out bikes. Hoy in particular is worth looking at for older children moving onto 24 or 26 inch bikes because the geometry is designed for performance riding.
Specialized, Trek and Giant all make kids' bikes through their dealer networks. These are generally good bikes, though heavier than the specialists. Decathlon's Btwin range is genuinely good value in the lower price brackets and worth considering if you are on a tight budget.
Passing the bike on
A well-maintained kids' bike can pass through three or four children and still be worth selling. The trick is to keep it out of the rain when not in use, wipe the chain occasionally, and keep the tyres inflated so the rims do not get damaged by kerbs.
When it is time to sell, photograph the frame number and original receipt if you have one. Cyclesite checks every listed bike against UK stolen-bike databases. Kids' bikes are stolen surprisingly often, and having the paperwork ready speeds up the listing process.