No universal tire-size-to-PSI chart can safely replace the vehicle placard. Use the door-jamb cold PSI for the approved OE configuration; use professional manufacturer data for a changed fitment.
Why identical tire sizes use different PSI
| Information | Encoded by tire size? | Why it matters |
|---|---|---|
| Width, aspect ratio, rim diameter | Yes | Determines nominal geometry, not vehicle pressure. |
| Front and rear axle requirements | No | Vehicle manufacturers may specify different axle pressures. |
| Vehicle load and approved configuration | No | The placard ties pressure to a vehicle fitment. |
| Load index and load range | Not in 225/60R17 alone | A full service description and valid load data may be required. |
What number should you use?
- Original size: use the driver-side Tire and Loading Information label or owner’s manual.
- Passengers or cargo: use a loaded-vehicle value only if the vehicle manufacturer provides one.
- Changed size/load range: consult the vehicle or tire manufacturer or a qualified tire professional.
Sources: NHTSA TireWise and 49 CFR § 571.110.
Frequently asked questions
Can tire pressure be calculated from tire size?
No. Tire size alone does not include the vehicle load distribution, approved fitment, axle requirements, or manufacturer calibration needed to set operating pressure.
Is there a reliable PSI chart by tire size?
A size-only chart cannot provide a vehicle-specific recommendation. Use the Tire and Loading Information label or owner’s manual for an original-equipment fitment.
What if I changed tire size or load range?
Consult the vehicle manufacturer, tire manufacturer, or a qualified tire professional. A valid replacement calculation needs more than dimensions and may require applicable load/inflation data.