Tire mounting and balancing

What a mount and balance includes

• The old tire comes off the wheel.
• The new tire goes on, and the bead (the edge that seals against the wheel) is seated so it holds air.
• A new valve stem, or a service on the TPMS sensor if the wheel has one.
• Computer balancing, with weights added where the wheel needs them.
• Pressure set to the number on the driver's door placard.
• Lug nuts tightened to the carmaker's spec.

It is all done while you wait. We mount new tires and used tires, on your wheels or on wheels you buy from us.

Why the valve stem matters

The valve stem is where the air goes in. Rubber stems age and crack, and a cracked stem leaks as surely as a nail does. On cars with tire pressure sensors, the sensor is part of the stem. The small seals and the nut that hold it should be replaced each time it is serviced, so the sensor keeps sealing.

What balancing does

No tire and wheel is perfectly even. One spot is always a little heavier than the rest. At highway speed, that heavy spot tugs the wheel many times a second, and you feel it through the car.

A balancing machine spins the wheel and finds the heavy spot. We add small weights on the opposite side so the wheel turns evenly. Weights either clip onto the edge of the rim or stick to the inside of the wheel, depending on the wheel.

We balance on a Hunter Road Force Elite, which also presses a roller against the tire while it spins to check how evenly it rolls, not just where it is heavy.

Static and dynamic, in plain words

Static imbalance is extra weight at one point around the tire. It makes the wheel hop up and down. Dynamic imbalance is extra weight toward one side of the tire's width. It makes the wheel wobble side to side. A computer balancer measures both and tells us where the weights go on each side of the wheel.

How an out-of-balance tire feels

The usual sign is a vibration that shows up once you get to highway speed. Tire sellers put it at roughly 45 mph and up. Where you feel it tells you which end of the car to look at.

• Shake in the steering wheel: usually a front tire.
• Shake in the seat or the floor: usually a rear tire.
• A vibration that started after a pothole or a curb.
• A tire that was just repaired, or a weight that fell off.
• Patchy, uneven wear on the tread.

Low-profile tires, the thin ones on bigger wheels, show an imbalance sooner than tall ones.

Guide: rotation, balance and vibration

If it still shakes after balancing

Balance fixes one cause of vibration, not all of them. If the shake stays after a good balance, the usual suspects are a bent wheel, a tire that is out of round, worn suspension parts, the brakes, or the alignment.

• A shake only when you brake points to the brakes.
• A pull to one side points to the alignment.
• A shake that came with a hard hit points to a bent wheel or a damaged tire.

Tell us what you feel and at what speed. We check the wheel and the tire before calling it a balance problem.

What happens when you come in

1. Walk in any day we are open. No appointment.
2. Tell us what you need: tires mounted, a shake you want gone, or wheels to go on.
3. We look at the tires and wheels. We tell you what it needs and the price before any work starts. No surprise fees.
4. We mount and balance while you wait. The Wi-Fi and the restroom are yours to use.
5. We set the pressure, tighten the lug nuts, and you drive out on it.

After you drive away

General guidance from tire and wheel sellers is to have the lug nuts checked again after the first 50 to 100 miles on newly mounted wheels, because they can settle. Stop by and we check them.

Check the pressure against the door placard when the tires are cold, before you drive. Rotating on the schedule in your owner's manual keeps the set wearing together, and a balance at the same time catches a new shake early.

Related services and tires

Wheel alignment, with a before and after printout

Flat repair

New tires from the major brands