Tire Basics | Costco Tires (2023)


why balance is important

Balancing is the balancing of the weight of the tire and wheel after the tire has been installed. When one area is heavier or lighter than the others, the wheel is out of balance. This can cause eccentric tread wear and vibration, increasing pressure on the front end and causing premature wear.

when to balance

You should balance your wheels whenever you change tires, move or remove counterweights, and buy new tires. Of course, at the first sign of vibration or irregular tread wear, your car deserves a thorough check for wheel balance and alignment, as well as worn or defective mechanical components.

how the wheels are balanced

To balance a wheel, a mechanic will use a wheel balancer to determine where the hard spots are. Weights are then placed on the outside or inside of the wheel to counteract the centrifugal force acting on the heavier areas as the wheel spins. This avoids vertical bouncing (static balancing) and lateral swinging (dynamic balancing).

Rotate Tips

Regular rotation will help extend the life of your tires and save you time and money in the long run. While spinning, each tire and wheel is removed from the vehicle and placed in a different position. This ensures that all tires wear evenly and last longer. If your vehicle's owner's manual doesn't specify a deadline, tires should be replaced every 10,000km to 12,000km. If you have a full spare tire, it should be included in your rotation.


Why Alignment Matters

Positioning is generally understood as the adjustment of the front and rear suspension components of a vehicle. Proper alignment will keep your vehicle running properly and help extend the life and performance of your tires.

When is alignment checked?

Your vehicle's positioning can get out of control due to everyday bumps such as potholes and railroad crossings or more serious accidents. Alignment should be checked if:

  • You know what you hit.
  • You will see a wear pattern on the shoulder of the tire.
  • You notice a difference in the handling of your vehicle

how the wheels line up

Alignment involves adjusting the angle of the wheels so that they are parallel to each other and perpendicular to the ground. The three most important alignment adjustments are camber, caster and toe.


Camber is the angle (in degrees) of the wheel when viewed from the front of the vehicle. Positive camber is when the top of the wheel protrudes from the center of the vehicle. Negative camber is when the top of the wheel is tilted towards the car. If the wheel is too far off center, uneven wear will occur. Camber is designed and tuned for each car to keep the tire flat on the outside of the turn when cornering. If the positive camber is too high, the outside of the tire will wear out. Too much negative camber wears down on their insides. If the camber settings of the front wheels differ too much, the vehicle will tend to drive sideways.


Caster is the forward or rearward inclination of the steering shaft, measured from the top of the tire when viewed from the side. The axle is formed by an imaginary line extending through the upper and lower knuckles. This line extends through the upper and lower ball joints on vehicles with a wishbone and the lower ball joint on vehicles with a strut to the center of the strut mount.

A wheel has positive caster if the angle is pointing towards the rear of the vehicle. If the angle is too far ahead of the front of the vehicle, the wheels will have negative caster.

Caster is set to allow your car to drive in a straight line. Positive caster makes your front wheels behave as if your car is being pulled from the front, making them line up behind the towing point like a child's toy.

Another example is the steering wheel on furniture or some shopping carts. When you push a shopping cart with casters, it tends to roll in a straight line because the wheels line up or lag behind the point of traction. The greater the trail distance, the greater the tendency to roll in a straight line. The vehicle's caster setting is adjustable to increase or decrease the effective caster distance.

Caster angle affects a vehicle's low-speed steering, high-speed stability, and how straight a vehicle is (center feel). Too little caster can cause your car to "walk" and feel unstable at high speeds. Too much caster can result in hard steering and can lead to excessive bumps and shakes in the road. Caster angle has no effect on tire wear.


The toe angle is the difference between the front and rear distances of the tire. Usually, the tires are adjusted parallel to each other. When the treads are brought closer together, the wheels toe in. While the rear wheels of the tires are closer together, the wheels are toe-in.

The toe setting affects the handling characteristics of the vehicle when cornering. Toe-in can cause understeer when entering a corner and make the car feel like the rear end is trying to get closer to the front end. Outswing can cause oversteer in corners and make the car feel like it's "hurling" into the corner.

If the tire has too much toe-in, the tread will "wear" from the outside edge. If they are turned outward, the wear will start from the inside. This type of wear is called "feathering" and can be felt by running your hands over the tire's tread.

Filling pressure

Proper air pressure in a tire is critical to the proper performance and life of the tire. Not to mention the ride quality and safety of the vehicle. Your tires support the full weight of your vehicle. If they are under- or over-inflated, they will not be able to do their job properly. Operating tires with insufficient air pressure can also lead to sudden tire damage.


We recommend checking the air pressure once a month and before long trips. Whether you have a full spare or a mini spare, make sure it's properly inflated.

Recommended pressure

Always inflate tires to the pressure recommended by the vehicle manufacturer. This information can be found in the owner's manual and usually on a sticker on the vehicle's door jamb, fuel filler cap or glove box door.

Best inflation time

Air expands when hot and contracts when cold. To get accurate pressures, always check the pressure when the tires are "cold" - at least three hours after the vehicle has stopped and before driving a mile. It's best to inflate your tires in the morning before the weather gets hot.

For example, a car tire initially inflated to 35 psi may lose 1/2 psi per month. Significant seasonal changes in temperature also affect air pressure, as cold ambient temperatures cause air pressure to decrease.

Valves and Bonnets

Tire valves are a very important maintenance item to keep your tires inflated. Usually made of rubber, these valves wear out over time and should be replaced when you buy new tires. Cracked, damaged rubber valve stems can bend due to centrifugal force and cause air leaks when driving at high speeds.

The valve cover is also an important part. Invest in a quality valve cap that will retain the inflation air should the valve core fail for any reason. The valve cover also prevents moisture from freezing, which can compress the valve plug and cause air leakage. The cap also keeps out dust and dirt particles that can also prevent the spool from functioning properly and can cause air leaks.

Inflationary pressure

Buy a good pressure gauge and check its accuracy with a tire dealer.

Beware of public measuring devices at gas stations. They are often abused and unreliable.

The final decision to install tires on a vehicle is made by the Manager or Supervisor at the Costco Tire Center. Tires must meet all vehicle manufacturer safety standards and regulations.

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