What Actually Happens During a Tire Mount and Balance

From the old tire coming off to the torque wrench going on, the steps in a proper tire install and the shortcuts that cause vibration and leaks later.

A tire install looks simple from the waiting room: the wheel comes off, the tire changes, the wheel goes back on. The difference between a set of tires that runs smooth and leak-free for their whole life and a set that vibrates and goes flat is in a dozen small steps that are easy to skip. Here is what a proper one involves.

Before anything comes off

We check the placard, confirm the new tires match the size and load rating the vehicle calls for, and check the DOT date code on the new tires so nothing old goes on. On a vehicle with TPMS we note which sensors are where. The lug nuts come off with an impact gun; that is the only time one is used on them.

Dismounting

The valve core comes out to deflate the tire fully. The beads are broken loose from the rim with the machine's bead breaker, carefully on alloys and around the TPMS sensor. The tire is lifted off the wheel. What is left is a bare rim, and this is where most of the important work happens.

The wheel inspection nobody watches

• Bead seats cleaned. Oxide, old rubber and old sealer are removed back to clean metal. A dirty seat is tomorrow's bead leak.
• Rim checked for damage. Bent lips, cracks at the spokes, corrosion pitting. A wheel with a problem gets flagged before a new tire goes on it.
• Valve stem replaced or serviced. Rubber stems are replaced. TPMS stems get a new seal, nut and core.
• Old wheel weights removed and the adhesive residue cleaned off so new weights stick.

Mounting

Bead lubricant goes on both beads. Not soap, not grease — a lubricant made for the job that dries and does not let the tire creep on the rim. The tire goes on with the machine, taking care not to snag the bead on the rim edge, and noting any directional or asymmetric markings so the tire ends up facing the right way.

The beads seat with a burst of air. They should pop into place evenly and the guide ring moulded into the tire should sit the same distance from the rim all the way around. A bead that is seated unevenly is a vibration that no amount of balancing fixes.

Balancing

The wheel goes on the balancer, which spins it and reports where weight is needed on the inner and outer planes. Weights are applied — clip-on for steel wheels, adhesive for most alloys — and it is spun again to confirm. The target is zero on both planes. We explain what this fixes and what it does not in balancing versus alignment.

Back on the vehicle

1. 1The hub face is cleaned of rust and debris so the wheel sits flat.
2. 2Lug nuts are started by hand.
3. 3They are tightened in a star pattern in stages.
4. 4Final torque is set with a torque wrench to the vehicle specification, not with an impact gun.
5. 5Pressure is set to the placard or, on LT tires, for the load.
6. 6TPMS is relearned if the vehicle needs it, so the light goes out and stays out.

Then a short test drive if anything about the job warrants it, and the customer is told to come back or check the torque after the first fifty to a hundred miles. The reasons for that are in our post on wheel torque.

Frequently asked questions

How long does a set of four take?

Done properly, with the wheel inspection and the torque wrench, a set of four on a normal vehicle is usually under an hour once the tires are in hand. Stocked sizes are same-day.

Do you balance used tires?

Every tire we fit gets balanced. Used tires often need more attention because they have worn unevenly on another vehicle.

Why does the TPMS light come on after new tires?

Either the sensor positions changed and the vehicle needs a relearn, or a sensor was damaged. We do the relearn as part of the job.

Tire replacement done in the bay, with every step on the list. 13209 Frankford Ave, Suite 29, Lubbock, or (806) 458-2709. Drivers make the trip in from Tahoka and across the South Plains for it.