Dynamic balancing a tire

Part 1. Preparation and safety

Objective

• Dynamically balance a tire and wheel rim assembly.

Personal safety

Whenever you perform a task in the workshop you must use personal protective clothing and equipment that is appropriate for the task and which conforms to your local safety regulations and policies. Among other items, this may include:

• Work clothing - such as coveralls and steel-capped footwear
• Eye protection - such as safety glasses and face masks
• Ear protection - such as earmuffs and earplugs
• Hand protection - such as rubber gloves and barrier cream
• Respiratory equipment - such as face masks and valved respirators

If you are not certain what is appropriate or required, ask your supervisor.

Safety check

• Embedded objects may fly off the tire when it is spinning on the wheel balancer, so wear safety glasses.
• If the wheel balancer is fitted with a safety hood, ensure it is in place when the wheel is being rotated.
• Make sure that you understand and observe all legislative and personal safety procedures when carrying out the following tasks. If you are unsure of what these are, ask your supervisor.

Points to note

• If the vehicle has directional or asymmetric tires, ensure that they are refitted to their correct position.
• Some wheels require a specific design of wheel weight. If the weights fitted to the wheel are not the correct type, they will fly off when the wheel is turning, causing possible injury or damage.

Part 2: Step-by-step instruction

1. Prepare the vehicle
   Prepare the vehicle by loosening the lug nuts, and then raise the vehicle into a comfortable working position. Check that the tires fitted to the wheels on the vehicle are not mixed with both radial and bias type tires. If there is a mixture, the bias tires should be installed on the front and the radials on the rear, when refitting the wheels.
2. Remove the wheels and tires
   Mark the wheel in relation to its location on the vehicle and then remove it. This is so that there is no chance of mixing up the wheel’s position to the hub when replacing it.
3. Mount the wheel on the balancer
   Check and adjust the tire pressure before balancing the wheel. Mount the wheel and tire on the balancer, putting the inside part of the tire on first. Secure the wheel with the hub nut assembly.
4. Determine balancing settings
   Measure the width of the rim with a rim caliper, the location of the flange on the wheel with a gauge, and the diameter of the wheel. Input this data into the balancers computer, if fitted, in accordance to the equipments instructions. If no computer is fitted, set the data settings manually according to instructions. Lower the safety hood over the wheel.
5. Check the tire balance
   Turn the balancer on to spin the wheel. Read the balancing machine analysis, which is normally displayed visually on the machine, and tells you whether the wheel is out of balance, and if so how much weight to use and where to put it to balance the wheel. If the wheel is out of balance you should remove the old weights and recheck the balance of the wheel before adding new weights.
6. Correct the balance and recheck
   Install the weights recommended by the machines display, using the correct fixing method for the weights. The type of weight and method of fixing, depends on the type and construction of the wheel that the weight is being fitted to, so always refer to the wheel manufacturers specifications when doing this part of the job. Now re-spin the wheel to check for accuracy of the balancing job and to confirm that balance has been achieved. A reading of zero on both sides of the wheel means the wheel is ready to reinstall on the vehicle. Repeat the process for the rest of the wheels and tires.
7. Refit the wheels and tires to the vehicle
   Refit the wheels to the vehicle using the correct procedure, remembering to lower the vehicle to the ground before torquing the lug nuts to specification using the correct tightening sequence.