GM Service Manual Online
For 1990-2009 cars only

Tires need the correct amount of air pressure to operate effectively.

Notice: Do not let anyone tell you that under-inflation or over-inflation is all right. It is not. If your tires do not have enough air (under-inflation), you can get the following:

   • Too much flexing
   • Too much heat
   • Tire overloading
   • Premature or irregular wear
   • Poor handling
   • Reduced fuel economy
If your tires have too much air (over-inflation), you can get the following:
   • Unusual wear
   • Poor handling
   • Rough ride
   • Needless damage from road hazards

A Tire and Loading Information label is attached to your vehicle's center pillar, below the driver's door latch. This label lists your vehicle's original equipment tires and their recommended cold tire inflation pressures. The recommended cold tire inflation pressure, shown on the label, is the minimum amount of air pressure needed to support your vehicle's maximum load carrying capacity. For more information regarding how much weight your vehicle can carry, see Loading the Vehicle .

How you load your vehicle affects vehicle handling and ride comfort. When driving with less than the maximum load capacity allowed for your vehicle, you can set tire inflation pressure to the recommended amounts shown in the following chart. Never load your vehicle with more weight than it was designed to carry.

Tire Size

Recommended Cold Tire Inflation

Occupant and Cargo Weight:

470 lbs (210 kg) or Less

Occupant and Cargo Weight:

Up to 740 lbs (330 kg)

(Vehicle Capacity Weight)

Front Tires

Rear Tires

Front Tires

Rear Tires

245/45ZR17 95W

30 psi (210 kPa)

30 psi (210 kPa)

35 psi (240 kPa)

35 psi (240 kPa)

235/40ZR18 91W

33 psi (230 kPa)

33 psi (230 kPa)

33 psi (230 kPa)

39 psi (270 kPa)

T145/70R17 96M

(Compact Spare)

60 psi (420 kPa)

60 psi (420 kPa)

60 psi (420 kPa)

60 psi (420 kPa)

When to Check

Check your tires once a month or more.

Do not forget your compact spare tire. It should be at 60 psi (420 kPa). For more information about your vehicle's compact spare tire, see Compact Spare Tire .

How to Check

Use a good quality pocket-type gage to check tire pressure. You can't tell if your tires are properly inflated simply by looking at them. Radial tires may look properly inflated even when they're underinflated. Check the tire's inflation pressure when the tires are cold. Cold means your vehicle has been sitting for at least three hours or driven no more than 1 mile (1.6 km).

Remove the valve cap from the tire valve stem. Press the tire gage firmly onto the valve to get a pressure measurement. If the cold tire inflation pressure matches the recommended pressure on the Tire and Loading Information label, no further adjustment is necessary. If the inflation pressure is low, add air until you reach the recommended amount.

If you overfill the tire, release air by pushing on the metal stem in the center of the tire valve. Recheck the tire pressure with the tire gage.

Be sure to put the valve caps back on the valve stems. They help prevent leaks by keeping out dirt and moisture.

High Speed Operation

Caution: Driving at high speeds, 100 mph (160 km/h) or higher, puts an additional strain on tires. Sustained high-speed driving causes excessive heat build up and can cause sudden tire failure. You could have a crash and you or others could be killed. Some high-speed rated tires require inflation pressure adjustment for high speed operation. When speed limits and road conditions are such that a vehicle can be driven at high speeds, make sure the tires are rated for high speed operation, in excellent condition, and set to the correct cold tire inflation pressure for the vehicle load.

Vehicles equipped with 245/45ZR17 95W size tires, do not require additional air pressure for high-speed operation. If your vehicle has 235/40ZR18 91W size tires, use the following chart to determine the cold tire inflation pressure when operating your vehicle under high-speed conditions.

Tire Size: 235/40ZR18 91W

Recommended Cold Tire Inflation Pressure for High Speed Operation

Occupant and Cargo Weight:

470 lbs (210 kg) or less

Occupant and Cargo Weight :

Up to 740 lbs (330 kg)

(Vehicle Capacity Weight)

Front Tires

Rear Tires

Front Tires

Rear Tires

36 psi (250 kPa)

36 psi (250 kPa)

39 psi (270 kPa)

44 psi (300 kPa)

When you end high-speed driving, return the tires to the cold inflation pressure shown on the tire and loading information label.