For 1990-2009 cars

All GM vehicles now use P-metric sized tires. P-metric tires are available in two load ranges, standard load (35 psi maximum) and extra load (41 psi maximum). Most passenger vehicle tires are standard load.

Most P-metric tire sizes do not have exact corresponding alpha-numeric tire sizes. For example, a P205/75R15 86H is not exactly equal in size and load carrying capacity to an FR78-15. For this reason, replacement tires should be of the same TPC specification number (same size, load range, construction) as those originally on the vehicle. If P-metric tires must be replaced with other sizes, a tire dealer should be consulted. Tire companies can best recommend the closest match of alpha-numeric to P-metric sizes within their own tire lines.

kPa | psi
--- | ---
140 | 20
145 | 21
155 | 22
160 | 23
165 | 24
170 | 25
180 | 26
185 | 27
190 | 28
200 | 29
205 | 30
215 | 31
220 | 32
230 | 33
235 | 34
240 | 35
250 | 36
275 | 40
310 | 45
345 | 50
380 | 55
415 | 60
6.9 kPa = 1 psi

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

Refer to Tire Placard Description or to Tire Inflation Pressure Specifications in Maintenance and Lubrication for tire inflation specifications.