Balancing Your Tires
Proper tire and wheel assembly balancing are critically important from a vehicle safety standpoint. An out-of-balance tire and wheel assembly can cause vibrations that affect ride and handling, shorten the life of tires, bearings, shock absorbers and other suspension components, and drastically increase or create irregular treadwear.
Types of Imbalance
There are two types of imbalance caused by heavy or light spots:
- Static imbalance occurs when there is a heavy or light spot in the tire, causing it to roll unevenly in an up-and-down movement.
- Dynamic imbalance occurs when there is unequal weight on both sides of the tire/wheel assembly centerline, causing a side-to-side movement.
Radial or Lateral Run-Out Imbalance
Run-out is often caused by improper bead seating on the rim or irregular placement of tire components during the manufacturing process. Bad bead seating is usually the result of improper mounting or the use of improperly made wheels. A small degree of this imbalance is acceptable, but too great a run-out causes vibration and excessive tire wear.
An out-of-round situation where vibrations are produced as the wheel spindle moves up and down.
A less-common, side-to-side or wobbling movement of the tire and wheel. Sensitivity of a vehicle to vibration from radial run-out is four to eight times that of wobble caused from lateral run-out.
Sources of Imbalance
Sources of imbalance can be traced to heavy or light spots in the tire, radial and lateral run-out variations within the wheel (such as thickness and welds), and rotor and axle imbalances.
Heavy or Light Spot Balancing
Heavy or light spot balancing is corrected either statically or dynamically, depending on the type of imbalance.
- Static Balance is achieved with a static "bubble" balancer but does not correct for dynamic imbalance.
- Dynamic Balance is achieved with a dynamic "spin" balancer where the tire/wheel assembly is balanced both statically and dynamically.
Run-out balancing is corrected depending on whether it is radial or lateral run-out.
- Radial run-out is achieved by rotating the wheel and tire assembly two stud positions on the hub, or by rotating the tire 180 degrees on the wheel.
- Lateral run-out balancing is achieved by using a run-out gauge to check both the tire and wheel.