Tyre Pressure Basics

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In short

Run the pressures on your vehicle placard (driver's door or handbook), checked monthly when cold. Typical car values sit between 30 and 36 psi (2.1–2.5 bar).

The basics that cover 90% of it

Check pressures monthly and before long trips, when the tyres are cold. The correct values are on the placard inside the driver's door or in the handbook — often two sets, for normal and loaded driving. Underinflation wears the shoulders, overheats the tyre and costs fuel; overinflation wears the centre and cuts grip.

psi, bar and kPa

psibarkPa
302.07207
322.21221
342.34234
362.48248

UK placards often quote bar and psi; US placards use psi. For quick conversion maths, use the unit converters at 247QuickTools, and for load-adjusted pressure calculations the calculators at 247Calculators.

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TPMS

Cars sold in the EU since 2014 and the US since 2008 have tyre pressure monitoring. TPMS warns of a deflating tyre but is no substitute for a monthly gauge check — most systems only alert around 20–25% under placard pressure, which is already enough to damage a tyre on a motorway run.

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Reference only. Nothing here is fitment or safety advice — always follow the vehicle manufacturer's placard or handbook.

FAQ

What should my tyre pressure be?

Whatever your vehicle placard specifies — it varies by car and load, typically 30–36 psi. The tyre size alone does not set the pressure.

How often should I check tyre pressures?

Monthly, and before any long or heavily-loaded trip, with the tyres cold. TPMS warnings come too late to substitute for this.

Related pages on this site

Last updated:

Data: computed reference values (ETRTO tyre-size arithmetic), build date 22 July 2026. Reference only — always follow your vehicle manufacturer's placard or handbook.