Tyre Pressure: PSI to Bar Guide
Read a door-jamb pressure label in either unit, understand cold-pressure rules, and avoid the sidewall-vs-label mistake.
From psi bar To
psi
bar
— conversions and counting
Reading the door-jamb label
The recommended pressure on the driver door jamb is cold pressure in PSI (US vehicles) or bar (most European vehicles). It is not the maximum pressure moulded into the tyre sidewall - that number is a limit, not a target.
Common recommended pressures converted
| Vehicle | PSI | bar | kPa |
|---|---|---|---|
| Small city car | 32 psi | 2.206 bar | 220.6 kPa |
| Compact saloon | 33 psi | 2.275 bar | 227.5 kPa |
| Family SUV | 35 psi | 2.413 bar | 241.3 kPa |
| Light van | 40 psi | 2.758 bar | 275.8 kPa |
| Road bicycle | 100 psi | 6.895 bar | 689.5 kPa |
| Motorcycle | 33 psi | 2.275 bar | 227.5 kPa |
What changes the reading
- Temperature: roughly 1 psi (0.069 bar) for every 10 F change in ambient temperature.
- Driving heats the tyre and raises pressure; always check before driving or after the car has rested for three hours.
- Altitude changes the gauge reading because gauges usually measure pressure relative to the surrounding air.
- A bar and a kgf/cm2 are close but not identical (1 bar = 1.0197 kgf/cm2); some older gauges use the latter.
Checklist before a long trip
- Read the door-jamb label, not the sidewall.
- Measure cold, with a calibrated gauge.
- Convert to the unit your gauge displays before pumping.
- Recheck after the first hour of driving; do not bleed a hot tyre down to the cold target.
Related pages
Frequently Asked Questions
Should I use the number on the tyre sidewall?
No. The sidewall shows a maximum limit. Use the cold pressure on the driver door jamb label.
How much does temperature change tyre pressure?
About 1 psi (0.069 bar) for every 10 F of ambient temperature change.
Should I let air out of a hot tyre?
No. Measure cold. Bleeding a hot tyre down to the cold target leaves it underinflated once it cools.