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Children: Choosing A Bike / Buying a Bike





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Infants / Child Seats Vs. Trailers Vs. Backpacks

Infant and Child Helmets

Buying a Bicycle

[For a discussion on the differences between adult bikes go to " Selection And Preparing A Bike"]

Bigger Kids: Which Bike to Choose and Buy As Children Grow

Kids grow so if they are in a child seat or trailer it won't be long until they outgrow it.  At 2-4 years they can move on to their own appropriately sized tri-cycle.  On a bicycle, kids can experience/learn the laws of inertia, pedaling, steering, braking and sitting on a saddle.  Tricycles don't do much to develop a sense of balance and they can be tippy (excluding low-lying "big wheels").

Most kids try a two-wheeler with training wheels around age 3 years.

Between the ages of 4 and 8 years most kids have developed sufficient physical coordination and agility, good balance, and master starting and stopping on a tricycle or training wheels so that they are ready to learn to ride a bicycle.  (Note: Kids generally lack the coordination and strength for hand brakes until at least 5.)  But, along with physical skills it also takes mental readiness (self-confidence) and motivation to learn to bicycle.  Some kids don't develop this until they are 10 or more years old.  It sometimes takes a lot of patience on the part of parents.  Interest and readiness to learn to ride a bike can manifests itself as questions about bicycles, a desire to ride with friends, talk about tricycles and training wheels as things for "babies," etc.  For tips on how to teach a kid to learn to bicycle click on this link.

Guide to Kid Bike Sizes: Children's bike sizes are determined by wheel diameter, not seat height and frame size as is the case with adult bicycles. The chart below should help you narrow your search, but it is not a substitute for an expert helping you find a bike that is most suitable.  A critical factor is the brakes.  Coaster brakes tend to be easier for young kids to use but they become less common as the bikes get bigger.  It can be a conundrum and dangerous when kids who are tall for their age fit bigger bikes with hand brakes that they can't operate well.  After kids outgrow children's bikes they'll move into small-framed adult bikes with 26 inch, 27 inch or 700c wheels, which are sized by the length of the seat tube.

Approximate Age Child's Inseam Wheel diameter
"bike size" *
2-4 years 14-17 inches
35-42 cm
12 inches Most come with training wheels, some are direct drive
4-6 years 16-20 inches
40-50 cm
14 inches Sold at many toy stores and big box stores.
5-8 years 18-22 inches
45-55 cm
16 inches Most have rear coaster breaks and pneumatic tires, some have front hand brakes.
6-9 years 20-24 inches
50-60 cm
18 inches not commonly available
7-10 years 22-25 inches
55-63 cm
20 inches Some models are multi-speed with hand brakes.
9+ years 24-28 inches
60-72 cm
24 inches Can have most of the feature of adult bikes.

* The size doesn't have any relationship to a real measure: It is certainly not the diameter of the rim. Generally the given size is closer to the tire/tyre diameter from tread-to-tread, but it is usually greater that this distance as well.

Note: the highest rate of bike-related head injuries is among boys 10-14 years old. For more information on helmets go to

Children under 12 years going solo on a tri-cycle or bicycle have a very limited range and don't get as much pleasure from simply cycling.  If you want to have a family outing with more cycling, as you child outgrows their child seat (age 3) or trailer (age 4), there are a couple of options to consider: tandems with kid-kits on the rear seat and third wheel kid's seats.  But you will still need destinations and activities that appeal to them.  Whether by tandem or third wheel, your children will be right with you no matter how fast you ride.  On a conventional tandem both cyclists have to pedal together, so when the adult pedals the child will have to pedal, unless they take their feet off the pedals.  The third-wheel cycles are designed to be free wheeling so the child can sit back and enjoy the ride anytime they want.  For links to equipment providers go to our link section and click on "technology & innovation".

Buying a Bicycle

There are literally hundreds of brands of kids’ bikes.  We don’t have the resources to collect, test and rank even a fraction of them, and we don’t know anyone who is.  A second problem for the consumer is that most of kids’ bikes are being sold at stores where you can’t trust the employees to know the difference between coaster brakes and side-pull brakes, and they similarly don’t know very much about the quality of bikes on the showroom floor.  A third problem is often these same employees assemble the bikes -- with no formal training as bike mechanics -- so even a good bike may be assembled wrong, making any rating dubious.  Given the circumstances, caveat emptor!

The best we can do is to try to educate consumers so that they can make a more informed decision about what is a good bike:

Even though kids’ bikes are small, to get the same quality in the bearings, machining, assembly, finishes and lightness as an adult bike would cost about the same.  But kids are expected to out grow their bikes in a year or two, so not many parents are willing to spend $300, $600 or $900 on a bike for their child.  Hence, you generally won’t find kids' bikes with the same quality found in adult bikes. Don't be surprised if your kid's bike weighs more than your own.


The first step in picking a bike is getting the right size.  Where adult bikes are sized by the frame (measured from the center of the bottom bracket to the top of the seat tube), bikes for children are sized by their wheels: 12”, 16”, 20” and 24”.  The bike should fit the child.   The rider should be able to dismount and comfortably straddle the bike flat footedly.  And then with a slight lean of the bike, get their bottom back onto the seat, put their foot on the pedal and, when the skill is there, ride away.  They shouldn’t be riding scrunched up with their knees hitting the handlebars and they shouldn’t be stretched out and unable to turn the handlebars easily.  At the slow speeds that kids start out riding at, steering by turning the handlebars is much more of an element of riding than at faster speeds where steering is done largely by leaning.  If there are training wheels on the bike, all of the steering is done with the handlebars.


If there is a range of prices available in your child's size, pick up a couple of bikes.  It’s likely the heavy bikes will be cheaper.  They are probably made of steel, where the lighter bicycles are built with some alloy metals.  Other than the ease of handling the bike, the one place the choice of metal can make a significant difference is in the wheels -- which we return to below in the discussion on brakes.


The next filter is seriously dangerous designs – eliminate these from the pool.  In the United States, the Consumer Product Safety Commission (CPSC) has taken care of most of this and a lot of the rest of the world has followed suit so you might not find any problems.  It is more likely to find dangerous features on older bikes.  Many of the major bad designs features of the past were thing in front on the rider -- along the top tube or handlebars -- that the rider could impale themselves on if they fell forward, like spiky gear shift knobs and large bolts.  Bikes without a derailleur should have well mounted chain guards.


The most important mechanical parts of a bike, overall, are the brakes.  Whatever has gotten the bike moving, you want your child to have control of getting it stopped.  Kids' bikes usually have either coaster brakes (brakes on the back wheel that are engaged by pedaling backwards), or handbrakes (brakes engaged by a grip on the handlebars that pinches brake pads against the rim of the wheel) or both.  Because of their small hand size and limited hand strength, the smallest kids’ bikes have coaster brakes.  Until a child’s hands are large enough and strong enough to effectively use a handbrake, they should rely on coaster brakes.  Before they move up to a multi-speed bike with a derailleur it is good for them to get some experience on a bike with both types of brakes so the get used to hand brakes, because bikes with a derailleur can only have hand brakes.

There are a variety of designs of brake mechanisms of handbrake activated brakes that go by names such as side-pull, center-pull, u-brakes, v-brakes, and cantilever.   There are good and bad quality products of each design so you will need to make your own assessment.  When accessing the braking mechanism you want to make sure that it is stiff enough and strong enough to handle the weight and speed of the rider (mass times velocity equals momentum, mv = p.)  If the bike only has brakes that work by rubbing on the wheel rims, it is best to have rims made of alloy.  Steel rims are chrome plated and are especially dangerous when they get wet, they have a low co-efficient of friction so it takes much longer to stop the bicycle—which can be dangerous!

If the brakes utilize brake pads, make sure the pads are aligned over the rim and the nuts are tight.  If properly adjusted, the drag-end (relative to the movement of the rim) of the brake pad should touch slightly before the lead end.  This is called “toe-in.”  If the brakes squeak when you brake they are not toed in properly.  On cheap bikes and kids’ bikes in general, it can be agonizing trying to get this adjustment correct -- without taking pliers and slightly twisting the brake caliper.


The CPSC requires the front wheel to have a safety mechanism so that even if the nuts on the axle come loose a ways, the front wheel won’t fall off.  Ideally the hub, spokes and rim should be metal.  If you hold the tire and try to wiggle the wheel from side-to-side, you shouldn’t feel any play, and the wheel should spin freely when you give it a spin.


Generally the frames are strong enough to handle moderate abuse.  An average strong adult should not be able to bend it by hand.  The frame should be in alignment.  You can check this by standing a couple meters in front or behind the bike and checking to see if the both wheels are in the same plane.  Check to make sure that the posts (seat post and handlebar stem) coming out of the frame are all bolted tight and can't be twisted.  The seat post and handlebar stem should also have been greased before they were assembled so that they don’t freeze up after the first couple of rains.  You can’t usually check this until you get the bike home.  After you take them out, grease them and reassemble them, make sure that the bolts are tight.

Drive train

The CPSC requires bike without a derailleur to have chain guards.  They can be very effective at keeping shoe laces and pant legs from getting caught between the chain and the chain ring and causing an accident.  Make sure they don’t rub against the chain, but keep them on.  The better crank arm/bottom bracket sets are three pieces, where the crank arms bolt on.  Second best is three piece sets where the crank arm are held in place with cotter pins.  Third place goes to one piece crank/bottom bracket sets.  These are most common on kids’ bikes.  In all cases, if you hold the pedal and try to wiggle the crank from side-to-side you shouldn’t feel any play, and when you spin the crank, the bottom bracket should spin freely.

We welcome additional information or anecdotes regarding any of this material.

Teach a Kid to Learn to Bicycle

Teach Your Child Well: Bicycle Safety Issues

Bicycle Safety Education Literature, Bike Helmet Offers and Safety Materials

IBF's Bicycle / Safety / Sustainability Bibliography / Reading List


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