Buying guide - Children's bikes
The main thing is to make sure that it's the right size. It's better to progress in stages than to fit your child onto the biggest bike they can pedal.
There are four main stages:
Pre-school (sub-16in wheel), Ages four to six (16in wheel), Ages six to 10 (20in) and Ages nine to 12 (24in). After that children can progress onto small adult bikes.
Here are some key considerations so that your child gets the new bike that they deserve.
Weight - Because children are smaller, lighter and less strong, weight makes a bigger difference to the fun and manoeuvrability of a child's bike than to an adult. A kilo saved from the bike of a six-year-old weighing 30kg is like 2.5kg saved from an adult's.
Wheels and brakes - Don't buy big wheels for small riders, they need scaling down too. While a larger wheel will roll over bumps and kerbs better, it will also be heavier (more inertia), and the steering will be less responsive. It's likely that the reach to the bars will be greater too, because the bottom bracket to front axle distance will be greater, and the bottom bracket itself will be higher. All these factors make for a slightly-too-large bike that bit more difficult to control than one that fits.
Brake levers must be within easy reach of the bars (is there an adjustment screw?) and easy to operate. Check that you can operate the brakes with only the little finger of each hand. Try to choose levers which are metal rather than resin.
Reach – is how far away you are from the bars. This is something that doesn't scale down well to children's bikes, particularly those of younger children. Most children are happier in a riding position that's more upright than adults would be, so they need the bars higher and closer. BMX bars are excellent on bikes with 20in or smaller wheels for that reason.
Suspension forks –Suspension forks on children’s bikes tend to be heavy, costly and generally non-serviceable. Rigid forks are better than bad suspension forks.
Pre-school - Children can learn to ride a two-wheeler from around three years old. It's much easier for them if they can balance and steer already. There are two ways to learn this: on a two-wheeled scooter or on a balance bike. (Stabilisers prevent a child from learning to ride a bicycle as balance is key.)
You can turn a starter bike into a balance bike by removing the crank arms and lowering the seat so your child can put both feet flat on the floor. Find a gentle slope and let them coast down it towards you. When they've got the idea, refit the pedals and get them to ride towards you.
First bikes will have 12in or 14in wheels. The bike should have: a low stand-over height; ball bearings in hubs, bottom bracket and headset; 90-100mm cranks; pneumatic tyres; at least one working brake.
Ages four to six - Bikes with 16in wheels still sometimes come with stabilisers: if so, remove them. All 16in wheel bikes come with a single speed gear.
Low overall weight will give a more easily manoeuvred bike. Avoid suspension and fat steel frames; thin steel tubes are fine. A lowish bottom bracket will enable your child to get a foot down from the saddle – which, as they can now ride properly, you'll be gradually raising. Cranks should be 100-120mm; the shorter the better. A chainguard of some sort will keep clothing or fingers out of the drivetrain.
By this age, children can hurtle along so easily operable brakes are a must. A light action V-brake or sidepull is fine up front, but less effective at the rear: the longer cable run means more friction so the lever is harder for the child to pull. A back-pedal coaster brake is a good solution.
Ages six to ten - 20in wheel bikes come with more gears. For a durable and easy to understand option, a three-speed hub gear is great. However five- and six-speed derailleurs are what you'll usually find. For casual riding single speeds can also be a good option: they're lighter, simpler and rarely develop problems.
Some 20in wheel bikes come with suspension forks. They'll be basic, unadjustable springs that children seem to love. There are two disadvantages: extra weight and less money to go round elsewhere. If the bike costs £120 or more, front suspension may be adequate. Rear suspension is poor unless you spend a lot more.
If the bike has a rear derailleur, get a derailleur guard for when the bike is dropped on its side. A kickstand is useful, as kids this age aren't good at propping their bikes up. Look for easy-to-use shifters. For cranks you’ll want 120-130mm; 140mm may do.
Ages nine to 12 - Spend in the region of £200 and you'll get a light(ish) weight aluminium mini-mountain bike that can be passed on to siblings. You’d want to see a 24in wheel bike with a single chainring and a decent, wide-range eight-speed cassette hub (ie. 11-30T). But you'll get a seven-speed, screw-on freewheel hub and most likely a triple chainset up front. If it's a double, look for a smaller inner ring (22 or 24) rather than a larger (42) outer.
Bike spec should compare to an adult's bike at the same price. So expect a micro-adjust alloy seatpost, a cartridge bottom bracket, an alloy flat or riser bar, a threadless stem, brand name V-brakes and a decent set of a wheels. They'll have off-road tyres, but a set of semi-slicks would be better for all-round use.
'Less is more' applies: instead of disc brakes, look for disc mounts for later upgrading. And look for a good suspension fork (adjustable preload and damping), not full suspension. The cranks will again be too long: you want 140mm, 150mm at a push. You may get 160mm.
Adapted from bikeradar.com