What training wheels do and why they matter for a 20-inch bike

Training wheels are a pair of small wheels mounted on either side of a bike's rear axle, positioned slightly above or at the same height as the main rear wheel. They keep the bike upright when your child is learning to pedal and steer, removing the balance challenge so they can focus on coordination and confidence. A 20-inch bike is the size most children use between ages 6 and 10, depending on their height and riding experience, so training wheels at this size are common for kids moving from smaller bikes or starting to ride for the first time.

The real purpose of training wheels is not to teach balance—it is to build pedaling rhythm and steering control in a stable environment. Once your child can pedal smoothly and steer without wobbling, the training wheels come off and balance work begins. Skipping this step or leaving training wheels on too long can actually slow down the transition to independent riding, because your child never learns to feel the bike shift under them.

Key Takeaways

  • Training wheels on a 20-inch bike should be adjusted so they barely touch the ground when the bike is upright, allowing the rear wheel to carry most of the weight.
  • A child is ready to remove training wheels when they can pedal smoothly for several minutes without stopping, steer in a straight line, and show no fear of the bike tipping.
  • Training wheels come in bolt-on and quick-release styles; bolt-on is more stable but takes longer to remove, while quick-release allows faster adjustment as your child progresses.
  • The most common mistake is setting training wheels too low, which props the bike up so much that your child never learns to balance and becomes dependent on them.

How to measure and install training wheels on a 20-inch frame

Before you buy training wheels, check your bike's rear axle diameter—most 20-inch kids' bikes use a 3/8-inch axle, but some use 10mm. Measure the distance from the center of the axle to the ground on your bike, then subtract about 1 inch. That is the wheel diameter you need. Most training wheel sets for 20-inch bikes come with 12-inch wheels, which is the standard size.

Installation depends on your axle type. If your bike has a bolt-through axle (a bolt that goes all the way through the center), you will remove the bolt, slide the training wheel bracket onto the axle, and reinstall the bolt hand-tight. If your bike has a quick-release lever, you will open the lever, slide the bracket on, and close it again. Either way, the training wheels should sit about 1 to 2 inches above the ground when the bike is upright and the rear tire is fully inflated. This gap is critical: it means the rear wheel is still doing most of the work, and the training wheels only catch the bike if it tips.

After installation, spin each training wheel by hand to make sure it turns freely and does not rub on the frame or tire. Check the bolts or quick-release again after your child's first ride, because vibration can loosen them.

Adjusting training wheels as your child gains confidence

Training wheels are not a set-it-and-forget-it part. As your child becomes more comfortable, you will gradually raise them so they touch the ground less and less. Start with the 1 to 2-inch gap mentioned above. After a week or two of regular riding, raise them another half-inch. Your child should not notice the change, but the rear wheel will start to do more balancing work.

Keep raising them in small increments every few weeks until they barely kiss the ground—just enough to catch the bike if your child loses balance, but not enough to support any real weight. At this point, your child is learning to balance without knowing it. The training wheels are there as a safety net, not a crutch. This gradual approach works better than removing them all at once, because your child's confidence stays high while their balance skills develop quietly in the background.

Watch for signs that your child is ready for the next adjustment: they stop looking down at the training wheels, they lean into turns without hesitation, and they can coast for a few feet without pedaling. These are signs the bike is becoming natural to them.

When and how to remove training wheels

Most children are ready to ride without training wheels between ages 5 and 8, though some take longer and that is normal. The readiness signs are more important than age: your child can pedal continuously for at least 5 minutes, they steer in a straight line without weaving, they can stop by braking (not by putting their feet down), and they show no fear when you mention removing the wheels.

Remove both training wheels at the same time, not one at a time. Removing just one creates an unstable, tilted feeling that confuses the learning process. Use the same method you used to install them—unbolt or unlatch both wheels, then check that the rear axle bolts or quick-release are tight.

The first rides without training wheels should happen in a wide, flat, empty space: a parking lot, a tennis court, or a long driveway. Have your child wear a helmet, wrist guards, and knee pads. Run alongside holding the seat, not the handlebars—holding the seat lets your child feel the bike's balance while you catch them if they tip. After a few rides, let go for short stretches. Most children find their balance within a few days of regular practice.

Common mistakes that delay learning

The most damaging mistake is setting training wheels too low. When they sit on the ground and carry the bike's weight, your child never feels the bike shift or lean, so balance never develops. They become dependent on the training wheels and often struggle when they come off. If your training wheels are touching the ground hard enough that you cannot slide a finger under them, they are too low.

Another common error is leaving training wheels on too long. Some parents keep them on for a year or more, thinking it is safer. In reality, the longer they stay on, the more your child expects them to be there, and the harder the transition becomes. Once your child can pedal smoothly and steer, training wheels should come off within a few weeks, not months.

A third mistake is removing training wheels before your child can pedal continuously. If your child still stops and puts their feet down every 20 seconds, they are not ready. Pedaling rhythm is the foundation—balance comes after. Rushing this step leads to falls and fear.

Training wheels versus balance bikes for 20-inch learners

Some parents wonder whether a balance bike (a pedal-less bike where children push with their feet) is better than training wheels. Balance bikes teach balance first, which is a real advantage. However, a balance bike is usually smaller (12 to 16 inches) and your child will outgrow it quickly. A 20-inch bike with training wheels lets your child learn on the bike they will use for several years, so they do not have to buy two bikes.

If your child has already used a balance bike, they may be ready to skip training wheels entirely on a 20-inch bike. If they have never ridden before, training wheels on a 20-inch bike work just as well as a balance bike, as long as you adjust them correctly and remove them on schedule. The key difference is that you have to be more intentional about raising them gradually—balance bikes force balance learning, but training wheels only teach it if you manage them actively.

Maintenance and safety checks for training wheels

Training wheels take a beating. Check them before every ride: spin each wheel to make sure it turns freely, look for cracks in the wheel rim or bracket, and make sure the bolts or quick-release are tight. Loose training wheels can catch on the ground or fall off mid-ride.

If a training wheel starts to wobble or rub, the bracket may be bent. This usually happens after a fall or a hard bump. A bent bracket should be replaced, not straightened, because it will not hold the wheel in the right position. Most training wheel sets cost between $20 and $50, so replacement is affordable.

Keep the wheels clean and dry. Mud and water can cause rust on the axle and make the wheels hard to turn. After riding in wet conditions, wipe the wheels dry and spin them a few times to clear water from the bearings.

Frequently Asked Questions

Can I use training wheels on a 20-inch bike with hand brakes instead of coaster brakes?

Yes. Training wheels work the same way regardless of brake type. Hand brakes are actually better for learning, because your child learns to use the brakes they will use on adult bikes. Make sure your child's hands are strong enough to squeeze the brake levers—if they cannot, coaster brakes are a temporary option until their grip strength improves.

What if my child is afraid to ride without training wheels?

Fear is normal and does not mean your child is not ready. Start by raising the training wheels so high they barely touch the ground, then let your child ride for a few days without knowing they are almost off. Once they feel confident, remove them. You can also practice in a grassy area where falls are softer, which often reduces fear faster than talking about it.

Do training wheels slow down a 20-inch bike?

Slightly. Training wheels add weight and drag, so the bike is a bit harder to pedal. This is not a safety problem—it actually helps your child build leg strength. Once training wheels come off, the bike will feel noticeably faster and easier to pedal, which is a fun reward for learning.

How long should training wheels stay on?

Most children use training wheels for 4 to 12 weeks of regular riding. Some need longer, some shorter. The timeline depends on how often your child rides and how quickly they build confidence, not on age. Riding three or four times a week speeds up the process compared to once a week.

Can I adjust training wheels while my child is riding?

No. Always stop and remove the bike from under your child before adjusting training wheels. Adjusting them while the bike is in use can cause them to catch or fall off, which creates a crash.