A coaster brake is a convenient feature found on around-the-town cruiser bikes. It is easy to engage, requiring only a swift backpedal, and virtually maintenance-free. The sealed unit of the brake protects it from sand and saltwater, if you live near the beach. Plus, having a bike void of brake cables makes for a great-looking ride. A wobbly back wheel indicates the need to adjust the hub on your coaster brake. It's an easy fix and will have you back on your head-turning cruiser in no time.
Stand your bike upright with your kickstand.
Use your socket or adjustable wrench to loosen the axle nuts on both sides of the rear wheel hub.
Set your bike down on its left side.
Stick the cone wrench into the right-side cone, located on the hub.
Turn the cone wrench clockwise until the cone just touches the bearings. Turn it back counterclockwise 45 degrees.
Tighten both axle nuts with your socket or adjustable wrench.
Stand your bike upright. Lift the rear wheel off the ground and move it left to right. Note any play.
Spin the back wheel to check there is free movement in the bearings of the rear hub.
Fine tune the adjustment, if needed. For wheel play, re-tighten the bearing cone. If there's resistance in the spin, loosen the bearing cone a hair.
Tips
The left bearing cone is immobilized by the reaction arm, therefore adjustments need only to be made on the right side.
English coaster brakes are built differently. When adjusting them, use a wrench to turn the whole axle.
Warnings
When reassembling your bike, make sure that the axle nuts are affixed tightly. Loose axle nuts could wobble off while riding and you could lose your back wheel.