Cracked Training Wheel: Stop Riding and Inspect

A cracked training wheel may show a split through its plastic body, missing tread material or damage around the hub. Because the support repeatedly takes side load when the bicycle leans, a crack can grow even during a slow ride. Remove the child, place the bike on firm level ground and inspect both support assemblies before deciding on replacement.

Find which material is damaged

Clean away surface dirt and rotate the support wheel slowly by hand. Look for a line that opens, a chunk missing, hub separation, sharp edge or tire material pulling from the wheel body. Compare with the other side. Keep fingers clear of brackets and do not press the bicycle sideways to load the damaged wheel.

Check the cause beyond the wheel

A curb strike, excessive clearance, bent bracket or loose axle hardware can overload a support. Inspect the bracket shape, wheel fastener and shared rear-bicycle axle without casual disassembly. Confirm the main rear tire is inflated correctly. Replacing the small wheel alone will not solve a distorted mount or incorrect setup.

Use an approved matched replacement

Diameter, width, axle bore and hardware order matter. Do not glue plastic, wrap missing tread or install a random skate wheel. Use the model's replacement and retain every specified washer, spacer and cover. A qualified mechanic should handle a bent bracket, damaged frame mount or uncertain rear-axle arrangement.

Reset and test the whole bicycle

With correct tire pressure and the bike upright on level ground, set both training wheels to the approved even clearance. Verify rear-wheel retention, chain movement and brakes. Let the child complete a slow straight ride, small turn and controlled stop. Recheck both supports for wobble, rubbing or shifted hardware afterward.

How the current product examples fit

The light-pink XJD training-wheel bike and blue XJD kids BMX offer support-wheel configurations across multiple sizes. Replacement wheels and bracket settings must match the selected size and delivered rear-axle hardware. See XJD Girls Bike with Training Wheels & Basket – Light Pink, XJD Kids BMX Bike with Training Wheels – Blue for the exact current options and specifications.

Quick checklist

• Remove the rider immediately.
• Inspect wheel body, tread and hub.
• Check bracket and rear axle too.
• Do not glue or wrap a crack.
• Reset clearance on level ground.

Common questions

Can a crack be used if it is only on the tread?

Missing or split tread can change rolling and expose sharp material. Obtain the manufacturer's replacement guidance before use.

Should both training wheels always touch the ground?

Follow the model's clearance instructions. A small even gap may be intended, but a cracked wheel is never a way to create it.

Explore related guides

Use the training-wheel-bike collection and kids-BMX collection to compare other suitable configurations without assuming every model has the same features.

Bottom line

A training wheel is a load-bearing support, not a disposable decoration. Replace the damaged matched part, correct the cause and verify the full rear assembly before riding resumes.