Training wheels attach to the rear axle with a bracket and bolt

Training wheels mount to the two sides of your bike's rear wheel using a metal bracket that clamps around the axle. The bracket comes with bolts that thread into the axle nuts — you do not need to remove the wheel. Most training wheel kits include the bracket, two wheels, bolts, and a wrench or hex key. The whole job takes about 15 minutes once you have the right tools.

Before you start, check that your bike's rear axle has nuts on both sides (not quick-release levers). Quick-release axles need an adapter kit, which some training wheel sets include and others do not. If your bike has a quick-release, confirm the training wheels you bought will work with it.

Key Takeaways

  • Training wheels bolt onto the rear axle nuts on both sides of the wheel, so you need a wrench or hex key that fits your axle bolts.
  • The bracket must sit level and centered behind the wheel, or the training wheels will drag unevenly and wear out fast.
  • Tighten the bolts firmly but do not over-tighten, which can strip the threads or crack the bracket.
  • Adjust the training wheel height so they just barely touch the ground when the bike is upright — they should not carry the bike's weight.

Gather the right tools and check the axle type

You will need the training wheel kit, a wrench or hex key that matches your axle bolt size (usually 10mm, 12mm, or 14mm), and a level or a straight edge to check alignment. Lay the bike on its side on a flat surface so you can see both sides of the rear wheel at once.

Look at the rear axle. If it has a nut on each side, you are ready to install. If it has a quick-release lever instead of a nut, you need an adapter. Some training wheel kits come with adapters that thread onto the quick-release axle; others do not. Check your kit's instructions before you buy, or bring your bike to the store to test the fit.

Position the bracket and insert the bolts

Slide the bracket onto the axle so it sits centered behind the wheel. The bracket should be level — use a level tool or check by eye that the metal arms on both sides are at the same height. If the bracket tilts, the training wheels will not sit evenly on the ground.

Insert the bolts through the bracket holes and thread them into the axle nuts by hand first. Do not use the wrench yet. Hand-tighten until the bolts are snug, then stop. This prevents you from cross-threading the bolts, which happens when you turn them at an angle.

Tighten the bolts in a crisscross pattern

Use your wrench or hex key to tighten the bolts. Tighten the left bolt a quarter turn, then the right bolt a quarter turn. Repeat this crisscross pattern until both bolts are firm. This keeps the bracket level as you tighten.

Stop when the bracket no longer moves side to side. You should not be able to wiggle it by hand. Do not over-tighten — if you feel strong resistance or hear a cracking sound, you have gone too far. Over-tightening can strip the bolt threads or crack the bracket.

Attach the training wheels and adjust their height

Slide each training wheel onto the axle stub on its side of the bracket. Most training wheels have a bolt or clip that holds them in place. Tighten or clip them so they do not spin freely on the axle — they should be fixed in position.

Stand the bike upright on flat ground. The training wheels should just barely touch the pavement. If they are too high, the bike will tip backward. If they are too low, they will carry some of the bike's weight and make pedaling harder. Adjust the bracket height by loosening the axle bolts slightly, moving the bracket up or down, and re-tightening. Check the height again after each adjustment.

Test the installation before riding

Spin the rear wheel by hand to make sure it turns freely and does not rub against the bracket or training wheels. If it does rub, loosen the axle bolts and shift the bracket slightly until the wheel spins without resistance.

Rock the bike side to side gently. The training wheels should stay in contact with the ground and support the bike evenly. If one training wheel lifts off the ground, the bracket is tilted. Loosen the bolts, level the bracket, and re-tighten.

Frequently Asked Questions

Can I install training wheels on any bike?

Most kids' bikes with axle nuts work fine. Adult bikes and bikes with quick-release axles need an adapter kit. Some BMX bikes and single-speed bikes have axles that are too short or oddly shaped for standard training wheels. Bring your bike to a shop if you are unsure.

How tight should the bolts be?

Tight enough that the bracket does not move when you push on it by hand, but not so tight that you strain to turn the wrench. If you feel the bolt getting harder to turn suddenly, stop — that is the point where it is snug. Going further risks stripping the threads.

Why do the training wheels drag on one side?

The bracket is tilted. Loosen the axle bolts, use a level to straighten the bracket, and re-tighten in a crisscross pattern. If the bracket is level but one wheel still drags, that wheel may be bent or not seated fully on the axle stub.

Do training wheels need to touch the ground all the time?

No. They should just barely touch when the bike is upright and still. As the rider leans into turns or shifts weight, one training wheel may lift slightly. That is normal. If both wheels are off the ground during normal riding, they are too high.

What if the axle bolts keep coming loose?

Use a wrench to hold the nut on the other side of the axle while you tighten the bolt. If the nut spins freely, the bolt will not tighten. Some people explore a small amount of threadlocker compound to the bolt threads, but this makes future removal harder.