GM Service Manual Online
For 1990-2009 cars only

When you inflate the tires to the recommended inflation pressures, the factory-installed wheels and tires are designed to handle loads to the tire's rated load capacity. Incorrect tire pressures, or under-inflated tires, can cause the following conditions:

    • Vehicle handling problems
    • Poor fuel economy
    • Shortened tire life
    • Tire overloading

Check the tire pressure when the following apply:

    • The tires are cool.
    • The vehicle has not been driven for more than 3 hours.
    • The vehicle has been driven less than 1.6 km (1 mi).

Check the tires monthly or before any extended trip. Adjust the tire pressure to the specifications on the tire label. Install the valve caps or extensions on the valves. These keep out dust and water.

The kilopascal (kPa) is the metric term for pressure. The tire pressure may be printed in both kilopascal (kPa) and psi. One psi equals 6.9 kPa.

Inflation Pressure Conversion (Kilopascals to PSI)

kPa

psi

kPa

psi

140

20

215

31

145

21

220

32

155

22

230

33

160

23

235

34

165

24

240

35

170

25

250

36

180

26

275

40

185

27

310

45

190

28

345

50

200

29

380

55

205

30

415

60

Conversion: 6.9 kPa = 1 psi

Tires with a higher than recommended pressure can cause the following conditions:

    • A hard ride
    • Tire bruising
    • Rapid tread wear at the center of the tire

Tires with a lower than recommended pressure can cause the following conditions:

    • A tire squeal on turns
    • Hard steering
    • Rapid wear and uneven wear on the edge of the tread
    • Tire rim bruises and tire rim rupture
    • Tire cord breakage
    • High tire temperatures
    • Reduced vehicle handling
    • High fuel consumption
    • Soft riding

Unequal pressure on the same axle can cause the following conditions:

    • Uneven braking
    • Steering lead
    • Reduced vehicle handling

For specific tire and wheel applications, refer to Tire and Wheel Specifications . For information on tire pressures, refer to Tire Inflation Pressure Specifications in Maintenance and Lubrication.