Steering wheel shimmies that occur at speeds of 55 to 60 miles per hour are often due to tire or tire balance problems. Vibrations that only occur during braking are usually due to bad brakes. The steering wheels of some vehicles shimmy due to a problem with the steering linkage.
Vibrations from tire balance problems often get worse as the driver increases the speed. The size and weight of the tire, wheel and vehicle all affect the speeds at which the vibration begins. Tire stores have balancing machines that allow them to test the tire balance to determine if it is causing a problem. Rebalancing the tires normally takes care of the problems.
The wear patterns on tires can also cause the steering wheel to shimmy. It is sometimes possible to rotate the tire on the wheel so the low spots on tire tread match the high spots on the wheel to eliminate the vibration.
Vibrations that occur when applying the brakes usually indicate a problem with the brake drum or rotor, depending on the style of brakes on the vehicle. If the brake parts have enough material, drivers can have a shop machine them to restore the balance. If the material is worn too thin, the drums or rotors require replacement.