Is your child ready for their first bicycle? Most youngsters learn the basics of pedaling, steering, and braking on a tricycle or "big wheel" cycle. And around age 4 they are ready to try a two-wheeler with training wheels.

A bike with training wheels gives children more practice riding without worrying about balance. Between ages 4 and 8, your child will likely develop enough coordination, agility, and a sense of balance to ride a bike without training wheels. But you are the best judge of your child. Some children are mentally ready at age 8 or even earlier. Others are not ready until age 10 or older. Let your child's interest in biking show you if they are ready. Keep in mind that most children younger than 5 don't have the strength or coordination to use hand brakes, advises the nonprofit International Bicycle Fund (IBF).

Many bicycles made for kids don't have the high quality of adult bikes, the IBF says. That's because a high-quality bike—no matter what the size—costs hundreds of dollars. And many parents don't want to spend that much on a bicycle their child is going to outgrow in 1 or 2 years. But buying a bike that is age-appropriate and safe for your child is worth the investment.

A bike should be the right size for your child. That means your child should be able to comfortably straddle the bike with their feet flat on the ground. Your child should be able to get onto the bike seat by slightly tipping the bike to one side. When your child is riding, their knees should not hit the handlebars. And their knees should not be so stretched out that your child can't maneuver the bike easily.

Kids' bikes are sized by wheel diameter instead of height of seat or size of frame, the IBF says. Here's an approximate guide:

• Ages 2 to 4. Wheel diameter, 12 inches; child's inseam, 14 to 17 inches. Most of these smaller bikes come with training wheels.
• Age 4 to 6. Wheel diameter, 14 inches; child's inseam, 16 to 20 inches. Most of these bikes have coaster brakes; some have hand brakes.
• Ages 5 to 8. Wheel diameter, 16 inches; child's inseam, 18 to 22 inches. These can have more than one speed with hand brakes.
• Ages 7 to 10. Wheel diameter, 20 inches; child's inseam, 22 to 25 inches. Some models are multispeed with hand brakes.
• Ages 9 and up. Wheel diameter, 24 inches; child's inseam, 24 to 28 inches. These often have the features of an adult bike.

Aside from fit, the most important parts of a bike are the brakes, the IBF says. Bikes for younger children often have coaster brakes, which work when the cyclist pedals backward. A young child doesn't have the hand size or strength for hand brakes. As your child grows, consider a bike with both a coaster brake and a hand brake. This gives them a chance to practice with both. Bikes with a derailleur only come with hand brakes.

When choosing a bike for your child, check the front wheel. Make sure it spins freely, but doesn't move when you try moving it from side to side. Look for a wheel with metal hub, spokes, and rim.

Examine the frame and make sure it is strong (you shouldn't be able to bend it by hand), the IBF says. Look at the bike front-on to see that the wheels are in line. Check all bolts to see that they are tight. Single-speed bikes should have a well-mounted chain guard. The guard shouldn't rub against the chain.

Don't forget the helmet when buying a bike for your child or yourself. The helmet should fit correctly. And you should insist that your child wear it whenever they ride. The Centers for Disease Control and Prevention says that the highest rate of bike-related injuries treated in emergency departments occur in children 10 to 14 years old.