How to Find the Correct Tyre Pressure for Your Car
Every vehicle has a manufacturer-specified tyre pressure that has been engineered for optimal safety, performance and fuel economy. Using the wrong pressure — even slightly — affects all three. Fortunately, finding the right figure for your specific car is straightforward once you know where to look.
Driver's Door Jamb Sticker
Open the driver's door and look at the edge of the door or the door frame. Most vehicles manufactured after 2000 have a sticker here showing the recommended front and rear tyre pressures, often for both standard and laden (heavily loaded) conditions.
Vehicle Handbook
Your car's owner's manual will always have a dedicated section listing the recommended tyre pressures, typically found under the "Wheels and Tyres" or "Technical Data" chapter. This is the definitive source and includes figures for different tyre sizes if your car has options.
Fuel Filler Cap
On some vehicles, particularly older models, the recommended tyre pressure is printed on a label on the inside of the fuel filler cap. It is less common now but worth checking if you cannot locate the door jamb sticker or handbook.
Understanding Tyre Pressure Markings: PSI, Bar and kPa
Tyre pressure is measured in three different units depending on the country and the equipment being used. In the UK, PSI (pounds per square inch) is the most common unit at petrol station air lines, though bar and kPa are also used. The conversion is straightforward:
Quick conversion: 1 bar = 14.5 PSI = 100 kPa. Most UK petrol station digital gauges allow you to select your preferred unit.
Typical Recommended Tyre Pressures
While every vehicle is different, the following table gives a useful general guide to typical tyre pressure ranges by vehicle category. These figures assume normal driving conditions with a standard load. Always verify the exact figure for your specific make and model before inflating your tyres.
Important: Always check your specific vehicle handbook for the exact recommended figures. The table above shows typical ranges only and should not replace the manufacturer's specification for your individual vehicle. Pressures may also differ depending on load (number of passengers and luggage) and whether you are towing a trailer or caravan.
Signs Your Tyre Pressure Is Wrong
Incorrect tyre pressure — whether too low or too high — affects vehicle safety, handling, fuel efficiency and tyre lifespan. Knowing the warning signs means you can take action before a small issue becomes a dangerous one.
Under-Inflated Tyres
Under-inflation is the most common tyre pressure problem and the most dangerous. Signs include:
- Sluggish, heavy steering — the car feels unresponsive and requires more effort to turn
- Increased fuel consumption — under-inflated tyres create more rolling resistance, costing up to 3% more in fuel
- Wear on the outer tread edges — the tyre flexes excessively and wears unevenly on both shoulders
- Longer braking distances — reduced contact patch stability impairs stopping ability
- Overheating and blowout risk — heat builds up rapidly inside a low-pressure tyre at motorway speeds
- Visually flattened sidewalls — a tyre that looks slightly deflated compared to the others is almost certainly low
Over-Inflated Tyres
Over-inflation is less common but equally harmful to safety and tyre longevity. Watch for:
- Harsh, bouncy ride — over-inflated tyres cannot absorb road imperfections and every bump is transmitted directly into the cabin
- Centre tread wear — the tyre bulges in the middle, and only the central section of the tread contacts the road, wearing rapidly
- Reduced grip in bends — a smaller contact patch means less traction when cornering
- Increased vulnerability to impact damage — a rigid, over-pressured tyre is far more likely to sustain a puncture or sidewall crack from potholes
- Visually drum-tight appearance — the tyre sidewall appears very stiff with no flex at all under load
Tyre Pressure Warning Light (TPMS)
Since November 2014, all new cars sold in the UK must be fitted with a Tyre Pressure Monitoring System (TPMS). The warning light looks like a cross-section of a tyre with an exclamation mark — it illuminates when any tyre drops approximately 25% below the recommended pressure.
What to do when the TPMS light comes on:
- Reduce your speed safely and pull off the road at the nearest safe location.
- Visually inspect all four tyres for obvious deflation, damage or a foreign object such as a nail.
- If a tyre is visibly flat, do not drive on it — call Apex Mobile Tyres on 07593 103323 for 24/7 emergency assistance.
- If all tyres appear normal, drive carefully to the nearest petrol station with an air line and check all four tyre pressures using a gauge.
- Inflate any low tyres to the correct pressure — the TPMS light should extinguish after a few minutes of driving.
- If the light remains on after inflating, the TPMS sensor itself may need attention — contact a professional.
Note: TPMS is a warning system, not a substitute for regular manual tyre pressure checks. Always check pressures monthly regardless of whether the warning light is on.
How to Check Your Tyre Pressure
Checking tyre pressure yourself takes less than five minutes and requires only a basic tyre pressure gauge, available from petrol stations or online for just a few pounds. Follow these steps to get an accurate reading every time.
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1
Check tyres when cold
Tyre pressure increases as the tyre heats up during driving. For an accurate reading, your car should have been parked for at least two hours, or driven fewer than two miles at low speed. If you check hot tyres, add 4–5 PSI to the reading to estimate the cold pressure — but re-check when cold for a precise figure.
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2
Find the correct recommended pressure
Check the driver's door jamb sticker or your vehicle handbook for the manufacturer's recommended front and rear pressures. Note whether you need the standard or laden figure based on your current load. Write it down or keep the page open on your phone while you check.
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3
Remove the valve cap
Each tyre has a small rubber or metal valve stem protruding from the wheel rim. Unscrew the black plastic cap and keep it somewhere safe — in your pocket, not on the ground where it can roll away. The valve is what allows you to add or release air.
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4
Press the gauge firmly onto the valve stem
Push the gauge straight onto the valve — not at an angle. You should hear a brief hiss if the connection is not perfectly sealed; reposition until it stops. On a digital gauge, the reading will appear instantly. On an analogue stick gauge, a bar will extend to show the pressure. Read the figure carefully.
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5
Inflate or deflate as necessary
If the pressure is too low, use the air line at a petrol station to add air — most modern digital air lines allow you to set the target pressure and they stop automatically. If the pressure is too high, use the gauge or a small pin on the gauge's back end to press the valve pin and release small bursts of air, checking regularly until you reach the correct figure.
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6
Replace the valve cap and repeat for all tyres
Screw the cap back on finger-tight — it keeps dust and moisture out of the valve. Repeat the process for all four tyres, and also check the spare if your vehicle has a full-size or space-saver spare wheel. Many drivers forget the spare and find it flat when they actually need it.
When Should You Check Tyre Pressure?
- Monthly: Tyre pressure naturally drops by approximately 1–2 PSI per month even without any puncture, due to air permeating through the rubber.
- Before a long journey: Always check before motorway driving or a trip of 50 miles or more.
- When carrying heavy loads: If you are towing or carrying maximum passenger and luggage loads, switch to the laden pressure figure.
- Seasonally: Tyre pressure decreases as outdoor temperatures drop in autumn and winter — approximately 1 PSI for every 10°F (5.6°C) temperature drop.
- After a TPMS warning: Check immediately and do not delay.
Tyre Pressure FAQs
Tyre Problems in Coventry or the West Midlands?
Persistent low tyre pressure can indicate a slow puncture — and a slow puncture left unattended can cause a sudden blowout at speed, which is extremely dangerous. Don't take the risk.
Apex Mobile Tyres is available 24 hours a day, 7 days a week across Coventry and the wider West Midlands. Whether you need an emergency tyre fitting on the roadside, a puncture repair, or a full set of new tyres fitted at your home or workplace, we come to you — typically within 60 minutes.