Tyre Pressure — Why It Matters and How to Check Yours

Tyre pressure is one of those things that sits on the to-do list forever — until something goes wrong. The reality is that incorrect tyre pressure is one of the most common preventable causes of breakdowns and accidents in the UK. It takes about three minutes to check, it’s free at most petrol stations, and it can genuinely save your life.

Why Tyre Pressure Matters

Under-inflated tyres are the bigger concern. When a tyre is under-inflated, more of the sidewall makes contact with the road — it flexes excessively with every revolution, which builds up heat rapidly. This heat weakens the structure of the tyre and can lead to a blowout, particularly at motorway speeds. Under-inflated tyres also reduce fuel efficiency (by as much as 0.4% per PSI below the recommended level) and cause uneven tread wear.

Over-inflated tyres have less contact with the road, reducing grip and braking performance. The central tread wears faster, and the tyre becomes stiffer and more vulnerable to impact damage on potholes.

How to Check Tyre Pressure

1. Remove the valve cap from each tyre

2. Press the pressure gauge firmly onto the valve — a hissing sound means it’s not fully seated

3. Read the pressure displayed

4. Compare with the recommended pressure for your vehicle

5. Inflate or deflate as needed using the air compressor

6. Replace the valve caps

Check cold tyres — pressure rises when tyres warm up from driving, so checking after a long journey will give a slightly higher reading than the actual cold pressure.

Where to Find the Correct Pressure

Your vehicle’s recommended tyre pressures are printed on a sticker inside the driver’s door frame, in the fuel filler flap, or in the owner’s handbook. They’re given in PSI (pounds per square inch) or BAR.

Note that many cars have different pressures for front and rear tyres, and there may be a different pressure specified when carrying a full load versus driving solo.

How Often to Check

Every two to four weeks is ideal. Always check before a long journey, before a heavily loaded trip (holiday luggage, towing), and after any significant change in temperature — cold weather causes tyre pressure to drop noticeably.

TPMS Warning Light

Modern cars are fitted with a Tyre Pressure Monitoring System (TPMS) that triggers a warning light when pressure drops significantly. This is a useful safety net, but it only activates when pressure is well below optimal. By the time the light comes on, the tyre has already been running under-inflated — so regular manual checks are still worthwhile.

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*Breakdown caused by a tyre fault? Call Jam’s Breakdown & Recovery on 07369 205 703 — we’ll get to you quickly and sort the problem.*