First-Order Tire and Wheel Assembly Vibration

The following are symptoms of first-order vibrations caused by tire and wheel assemblies:
- The vibration is always related to the speed of the vehicle.
If the vibration is affected by the speed of the engine, or if the vibration is eliminated by placing the transmission in Neutral, the vibration is NOT related to the tire and wheel assemblies.
- The vibration will feel like a shake, usually in the steering wheel or the seat.
- Tire and wheel vibrations that are felt in the steering wheel are most likely relate to the front tire and wheel assemblies.
- Tire and wheel vibrations that are felt in the seat or the floor are most likely related to the rear tire and wheel assemblies.
- This may not always hold true, but this is a general rule that may serve to initially isolate a problem to the front or the rear of the vehicle.
- The customer may complain of a waddle at low speeds of 8 - 56 Kph (5 - 35 mph).
- The frequency on the EVA will correspond to the first-order of tire rotation. This frequency will usually be in the 10 - 20 Hz range, depending on the speed of the complaint and the size of the tire. The smaller the tire, the faster the tire will rotate at any given speed.
- The range of the human ear begins at 20 Hz. For this reason, first-order tire vibrations rarely produce noise. The exception is when the tires display an irregular tread pattern or flat spots. This condition causes a growling or a slapping noise.