Car How to check tyre pressure and tread
Car · Beginner
How to check tyre pressure and tread
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A five-minute check of pressure and tread will tell you whether the tyres are safe to drive on. This guide is for a car sitting on its wheels, using a gauge and a tread-depth tool. It is not for taking a wheel off, repairing a puncture on the road, or judging a damaged sidewall from a photo — those are garage jobs.
Your call
Go or no?
Fancy giving it a go, or would you rather call a garage? There’s no wrong answer.
Right then. Here’s the kit, then the steps.
No problem. We’ll show you how to find a local garage.
At a glance
Shop the full kit
You can pick up the items below as you need them. Prices vary by shop and country, so we have not invented a figure here — check the live price before you buy. Shop links go to a product search on a local store for your country.
All-in-one kit
There is not usually a single boxed kit for this job. Buy the items below as you need them, and skip anything you already have.
Before you start
Safety
Stop and get a pro: Do not drive on a tyre that is under the legal tread limit, has exposed cord, a bulge, a cut in the sidewall, or a nail you cannot assess. Do not work under the car or loosen wheel nuts for this check. If you are unsure about a puncture or a warning light that stays on, find a garage or a tyre centre.
- Check pressure when the tyres are cold — before a long drive, not after. A hot tyre reads higher.
- Park on level ground, apply the parking brake, and keep clear of traffic if you are at the side of a road. A car park is safer.
- Do not exceed the pressure on the driver’s door card or handbook. More is not safer.
- If a tyre looks recently damaged or the car has been in a pothole or kerb strike, have it inspected rather than just pumping it up.
Prep that is worth doing
- Find the recommended pressures in the handbook, on the driver’s door pillar, or inside the fuel-filler flap. Note that front and rear, and a full load, can be different.
- Have a decent pressure gauge — many petrol-station airlines are rough, but they will do if you watch the reading.
- Know the legal minimum tread where you live (see the note above). The wear bars in the grooves are a quick visual clue, but a gauge is clearer.
Tools and materials
Check the live price at a shop you trust. Typical prices on this site, where they appear, were checked in the UK and may be out of date. Do not invent or assume a figure from this table. Shop links go to a product search on a local store for your country.
| Item | Why you need it | Typical price | Shop link |
|---|---|---|---|
| A tyre pressure gauge | Gives a reading you can compare with the handbook figure. Digital or analogue is fine if it is in good condition. | Typically £8–£20 at a UK shop. Check the live price. | |
| A tread-depth gauge | Measures the remaining tread in millimetres (or 32nds of an inch in the US). A 20p coin is only a rough UK check, not a measurement. | Typically £5–£12 at a UK shop. Check the live price. | |
| A portable compressor or access to an airline | So you can add air if a tyre is low. Stop if the tyre will not hold pressure. | Typically £20–£45 at a UK shop. Check the live price. | |
| Valve caps if any are missing | They keep dirt out of the valve. They are not a substitute for a working valve. | Typically £3–£8 at a UK shop. Check the live price. |
Shop this list:
Step-by-step
Check the pressures cold, then measure the tread in more than one place on each tyre, including the spare if you have one.
Find the correct pressures
Read the door card or handbook. Use the figure for the load you are carrying. If you only have bar or only have PSI, convert carefully — do not guess.
Check each tyre, including the spare if it is a full-size or spacesaver that you might use
Unscrew the valve cap, press the gauge squarely on the valve, and read it. If it is low, add air a little at a time and re-check. If it is high, let a little out and re-check. Refit the cap.
Look at the tyre as well as the number
Walk around the car. Look for bulges, cuts, exposed cord, objects in the tread, and uneven wear (worn on one shoulder often means a pressure or alignment problem).
Measure the tread
Push a tread-depth gauge into the main grooves, across the central three-quarters of the tyre, in more than one place around the circumference. Record the lowest reading. Compare it with the legal minimum where you live. If you are close to the limit, plan a replacement rather than waiting for a test fail or a wet-weather shock.
If a tyre will not hold pressure, or you find damage
Do not keep driving and topping it up. A slow puncture, a damaged valve or a sidewall injury needs a tyre centre. Many will not repair a sidewall, and some punctures in the shoulder cannot be patched.
Reset a tyre-pressure warning if the handbook says to, only after the pressures are correct
If the light stays on, there may still be a leak or a failed sensor. That is a garage job, not a reason to ignore the light.
General guidance only. Check our disclaimer.
Common mistakes
- Checking tyres when they are hot and assuming they are over-inflated. Wait until they are cold, or you will let out air they actually need.
- Only checking the front tyres. The rears and the spare matter too, and a spacesaver spare often has its own, higher pressure.
- Using the sidewall maximum pressure as the everyday figure. That number is a maximum, not the recommended running pressure.
- Measuring only the middle of the tread. Wear is often worse at the edges. Measure in more than one groove and around the tyre.
- Driving on a tyre at or under the legal limit “just to get home” on a fast road. In the wet, a worn tyre can lose grip suddenly. Arrange a replacement or a recovery truck if you need to.
FAQ
Is the 20p test enough in the UK?
It is a rough check: if the outer band of the coin is visible when you stand it in the groove, the tread may be close to 1.6 mm. It is not a substitute for a gauge, and it does not apply in countries with a different legal minimum.
My car has a tyre-pressure warning light. Do I still need a gauge?
Yes. The light tells you something is wrong; a gauge tells you the actual pressure. Reset the system only as the handbook describes, and only after you have corrected the pressures.
The inside edge of a front tyre is worn more than the rest.
That is often an alignment or suspension issue, not just pressure. A tyre centre can measure it. Keep driving on a badly worn inner edge and you can fail a test or lose a tyre.
Can I repair a puncture myself with a goo kit?
A temporary sealant can get you to a tyre centre in some cases, if the handbook allows it and the damage is in the tread. It is not a permanent repair, and it is the wrong answer for a sidewall cut or a tyre that has been run flat.
Would rather not DIY? Find a local garage
If a tyre is damaged, under the legal limit, or will not hold pressure, a garage or tyre centre can inspect it and fit a replacement. Do not drive on a tyre you already know is unsafe.
We may earn from shop links, at no extra cost to you. Disclosure