Common sense and good driving habits will afford maximum tire life. Fast starts, sudden stops and hard cornering are hard on tires and will shorten their useful life span. Make sure that you don't overload the vehicle or run with incorrect pressure in the tires. Both of these practices will increase tread wear.
Inspect your tires frequently. Be especially careful to watch for bubbles in the tread or sidewall, deep cuts or underinflation. Replace any tires with bubbles in the sidewall. If cuts are so deep that they penetrate to the cords, discard the tire. Any cut in the sidewall of a radial tire renders it unsafe. Also look for uneven tread wear patterns that may indicate the front end is out of alignment or that the tires are out of balance.
Inspect the tread for abnormal wear, check for nails or other foreign material embedded into the tire. To check for leaks, submerse the wheel assembly into a tub of water and watch for air bubbles.
Wheels must be replaced if they are bent, dented, leak air through welds, have elongated bolt holes, if wheel nuts won't stay tight, or if the wheels are heavily rusted. Replacement wheels must be equivalent to the original equipment wheels in load capacity, diameter, rim width, offset, and mounting configuration.
A wheel of improper size may affect wheel bearing life, brake cooling, speedometer/odometer calibration, vehicle ground clearance and tire clearance to the body and/or chassis.
Check runout in all directions (up and down, in and out) using a dial indicator. For aluminum wheels, maximum runout is 0.030 in. (0.762mm) For steel wheels, the specification is 0.045 in. (1.143mm). If the wheel causes a vibration and tire balance does not solve the problem, replace the wheel.
Good radial tires can produce a big advantage in slippery weather, but in snow, a street radial tire does not have sufficient tread to provide traction and control. The small grooves of a street tire quickly pack with snow and the tire behaves like a billiard ball on a marble floor. The more open, chunky tread of a snow tire will self-clean as the tire turns, providing much better grip on snowy surfaces.
To satisfy municipalities requiring snow tires during weather emergencies, most snow tires carry either an M + S designation after the tire size stamped on the sidewall, or the designation "all-season." In general, no change in tire size is necessary when buying snow tires.
Most manufacturers strongly recommend the use of 4 snow tires on their vehicles for reasons of stability. If snow tires are fitted only to the drive wheels, the opposite end of the vehicle may become very unstable when braking or turning on slippery surfaces. This instability can lead to unpleasant endings if the driver can't counteract the slide in time.
Note that snow tires, whether 2 or 4, will affect vehicle handling in all non-snow situations. The stiffer, heavier snow tires will noticeably change the turning and braking characteristics of the vehicle. Once the snow tires are installed, you must re-learn the behavior of the vehicle and drive accordingly.
- If equipped, remove the hub cap/wheel cover.
- Many GM W-Body vehicles use styled wheels with cosmetic covers over the wheel retaining nuts (also called lug nuts). Some models may use bright-finished metal caps, others may use a black plastic cap. Use a deep socket to unscrew these cosmetic covers.
- With the vehicle still on the ground, use a deep socket and a suitable breaker bar or ratchet to break loose, but do not unscrew the lug nuts.
- Raise and safely support the vehicle.
- Remove the wheel lug nuts.
- Since the tire and wheel assemblies were originally balanced as an assembly on the vehicle and since many professional tire shops may spin balance a tire and wheel assembly while mounted on the vehicle (so the brake rotor and hub are also included in the balance computation), a tire and wheel assembly should always be installed in the same location as removed. Mark the location of the tire and wheel to the hub. Many technicians will chalk the end of the topmost wheel stud and place a another chalk mark on the corresponding wheel opening. In this way, the tire and wheel assembly can be installed in the same relationship as when removed.
- Remove the tire and wheel assembly.
- Clean the wheel nuts, studs and the wheel and rotor mounting surfaces.
- Install the tire and wheel assembly aligning the locating marks made at removal.
- Tighten the wheel lug nuts by hand until they are snug. Then tighten the nuts in a 'star-shape' sequence, as shown in the accompanying figure, and torque to specification. Improperly tightened wheel lug nuts could eventually allow the wheel to come off while the vehicle is moving, possibly causing loss of control, personal injury and property damage.
- Tighten the lug nuts finger-tight. Then tighten in sequence to 100 ft. lbs. (140 Nm). Use of a torque wrench is important. Aluminum wheels will distort under uneven wheel lug nut pressure. Unequal torque can also distort brake rotors, causing uneven brake wear and pulsations in the brake pedal.
- Install the hub cap, if equipped. Install the lug nut cosmetic covers, if equipped.
- Lower the vehicle. With the vehicle on the ground, recheck the wheel lug nut torque.
General Motors says that penetrating oil has not been found to effective in removing tight wheels. However, if it is to be used, it should be applied sparingly to the hub surface only.
Excessive force such as hammering the wheel or tire can also cause damage. Use a rubber mallet to lightly tap the tire's sidewall. Sometimes wheels can be difficult to remove from the vehicle due to foreign material or a tight fit between the wheel center hole and the hub or rotor. These wheels can be removed without damage as follows:
- Tighten all wheel nuts on the affected wheel, then loosen each wheel nut two turns.
- Lower the vehicle to the floor.
- Rock the vehicle from side to side as hard as possible using one or more person's body weight to loosen the wheel, and/or rock the vehicle from DRIVE to REVERSE, allowing it to move several feet in each direction. Apply quick, hard jabs on the brake pedal to loosen the wheel.
For maximum satisfaction, tires should be used in sets of four. Mixing of different types (radial, bias-belted, fiberglass belted) must be avoided. In most cases, the vehicle manufacturer has designated a type of tire on which the vehicle will perform best. Your first choice when replacing tires should be to use the same type of tire that the manufacturer recommends.
When radial tires are used, tire sizes and wheel diameters should be selected to maintain ground clearance and tire load capacity equivalent to the original specified tire. Radial tires should always be used in sets of four.
When selecting tires, pay attention to the original size as marked on the tire. Most tires are described using an industry size code sometimes referred to as P-Metric. This allows the exact identification of the tire specifications, regardless of the manufacturer. If selecting a different tire size or brand, remember to check the installed tire for any sign of interference with the body or suspension while the vehicle is stopping, turning sharply or heavily loaded.
Tires must be rotated periodically to equalize wear patterns that vary with a tire's position on the vehicle. Tires will also wear in an uneven way as the front steering/suspension system wears to the point where the alignment should be reset.
Rotating the tires will ensure maximum life for the tires as a set, so you will not have to discard a tire early due to wear on only part of the tread. Regular rotation is required to equalize wear.
Some styled or "mag" wheels may have different offsets front to rear. In these cases, the rear wheels must not be used up front and vice-versa. Furthermore, if these wheels are equipped with unidirectional tires, they cannot be rotated unless the tire is remounted for the proper direction of rotation.
If they are mounted on wheels, store the tires at proper inflation pressure. All tires should be kept in a cool, dry place. If they are stored in the garage or basement, do not let them stand on a concrete floor; set them on strips of wood, a mat or a large stack of newspaper. Keeping them away from direct moisture is of paramount importance. Tires should not be stored upright, but in a flat position.