Check Your Tyre Pressure

How to check your tyre pressure

Checking your tyre pressures is simple, and you can do it yourself for free. It takes just a few minutes.

First, find your recommended pressures. You can find these in several places –

1) Your vehicle’s handbook

2) Stamped into the sill of the driver’s door

3) Inside your fuel cap.

Your recommended pressure is set by the vehicle manufacturer so will vary depending on the make and model of your car, whether it’s an Audi TT, Ford Focus Volkswagen Golf.

If you can’t find your recommended pressure, try our simple tyre pressure checker. Just enter your vehicle registration number and take a note of your pressures.

Once you’ve found your recommended pressure table, you will see that different pressures are recommended for different loads – for example if you’re driving on your own to work, the pressure setting will be different to your family holiday when the car is weighed down with extra bodies, luggage, pets etc.

TYRE PRESSURE GAUGE

You will need a pressure gauge to check your tyre's pressure. Remove the valve cap, attach the pressure gauge and check the reading. If you require more air, you can top up for free/a small charge at lots of filling stations. If your pressure is too high, air can be allowed to escape from the tyre while the valve cap is removed.

Once you have the correct pressure reading, remove the air hose, check the valve area is clean, and re attach the tyre valve.

If you'd rather someone else carried out your tyre check, for example if you don't have your own pressure gauge or can't find a tyre pressure machine at a local filling station, then please bring your car along to any National Tyres and Autocare branch and we'll check and adjust your tyres FREE of charge.

Types of pressure gauge

There are many brand names on the market, including those manufactured by the AA or tyre brands such as Michelin. Prices vary from under £5 to around £20.

Tyre pressure measurements

Pressure can be measured in bar pressure, or, in psi pressure. You can convert a bar pressure measurement into a psi pressure measurement using this online pressure conversion tool.

WHY DOES TYRE PRESSURE MATTER?

Maintaining the correct tyre pressure helps extend the life of your tyres, improves your vehicle's safety and improves your fuel efficiency.

Tyre life - tread wear

Your tyre's lifespan can be reduced by as much as 75% if your tyres are running at just 80% of the recommended pressure. If pressure falls to 60% (which we find is not uncommon), tyre life can be reduced by as much as 35%. Early signs of potential under-inflation are a rapid wearing on the outside edges of your tyres. If left unattended, this can quickly cause your tyres to become illegal.

Vehicle safety - blow outs

When tyres are under-inflated, there is not enough air in the tyre to support the vehicle's weight. This leads to the tyre's sidewalls being compressed by the weight of the vehicle causing them to flex beyond their normal limits. This abnormal flexing leads to heat building up in the tyre and dramatically increases the chances of a high speed blow out.

Fuel efficiency

Under-inflation increases the amount of the tyre's tread that is in contact with the road surface. Increased friction means that the tyre's ability to roll along the surface of the road is reduced (you might hear us refer to this as an increase in 'rolling resistance'). This means your vehicle needs to use more power to roll an underinflated tyre along the ground, leading to an inevitable increase in fuel consumption. Increased fuel consumption can lead to increased CO2 emissions from your vehicle, so correct tyre pressure can also lessen your environmental impact.

So, to sum up, correctly inflated tyres can make your tyres last longer, keep you and your vehicle safe on the road, and even help save money and the environment.

TOP 10 TYRE PRESSURE TIPS

1. Check your pressures once a month, before any trip and if you are changing the normal load of your vehicle.

2. Always check pressures when the tyres are cold (ideally when they have travelled less than 2 miles)

3. Find your correct pressure in your driver’s handbook, driver’s door sill or fuel filler cap

4. Increase pressures in accordance with driver’s handbook when the car is fully laden (e.g. when going on holiday)

5. Always use a reliable pressure gauge

6. Don’t forget to check ALL your tyres including the spare!

7. If you’re towing a vehicle, remember to check its tyres too.

8. Whilst checking your pressures, also look out for signs of tread wear, cuts or other damage.

9. Tyres lose pressure more quickly in warm weather, so be sure to check regularly in summer.

10. If in doubt, consult a fitter at National Tyres and Autocare.

PRESSURE AND RUN FLAT TYRES

Self supporting run flat tyres are designed to provide a run on period after deflation, so these tyres can keep running even when there is no air pressure. This is possible due to the tyre's reinforced sidewalls. The highly resilient rubber inserts support the weight of the car even when the tyre loses all its air pressure.

The range of the tyre when running on flat is dependent on the condition of use (i.e. vehicle load, vehicle speed and driving conditions). However, you should be able to keep ongoing for a minimum of 50 miles at a constant speed of no more than 30mph.

As it can be impossible to detect changes in pressure when driving on run flat tyres, these tyres may only be fitted to vehicles equipped with tyre pressure monitoring systems (TPMS). Run flat tyres can also be fitted to towing vehicles, again only if a TPMS is fitted to the vehicle.

Tyre Pressure Monitoring Systems

Some vehicles, including new Peugeots and Citroens, come equipped with a Tyre Pressure Monitoring System (TPMS). The TPMS constantly monitors tyre pressure and temperature, alerting the driver both visually and audibly when tyre pressure or temperature is abnormal. The TPMS monitors each tyre 24 hours a day and alerts the driver within 3 seconds of any abnormality.

For the driver, this means no checking of tyre pressures, reduced tyre wear and less fuel consumption plus reduced chance of premature tyre failure.

Following European Parliament legislation, from 1^st November 2012, every new car sold in Europe will have a TPMS fitted as standard. The rationale behind fitting TPMS is to provide an in-car early warning system for tyre pressure loss. Tyre safety organisations have estimated that up to 90% of cars on UK roads have tyres that are incorrectly inflated leading to increased fuel consumption and accelerated tyre wear. For the average family saloon, just a 6psi drop in pressure leads to a 20% increase in fuel consumption and 30% increase in tyre wear. Yet this tyre pressure reduction would rarely be identified under normal driving conditions particularly on low profile tyres.

As a by-product of having correct pressures, there will be benefits in safety by improved handling, reduced braking distances and risk of aquaplaning and economy with reduced tyre wear, decrease in fuel consumption and reduction in CO2. It is likely that by December 2012, over four million cars on UK roads will have TPMS.

TPMS Sensor Valve

TPMS RETROFIT SYSTEM

Most sensors have a life span of around 7 years. When sensors are replaced in the future, there need to be sensible procedures and equipment employed to reconfigure the new sensor into the vehicle's onboard diagnostics. For instance fitters will need to make sure that the TPMS is working before starting work on a customer's car, will need to measure the status of each sensor and offer replacements to the customer if a sensor is coming to the end of its battery life.

TYRE SURE TYRE PRESSURE MONITORING SYSTEM

The Tyresure TPMS monitors each tyre 24 hours a day and alerts the driver both visually and audibly within 3 seconds of any abnormality in tyre pressure or temperature.

• Completely wireless and CE Certified.
• Displays pressures in BAR or PSI.
• Bright clear colour LCD Display (Display size in mm: 84w x 51h x 20d).
• 7 Year TPMS sensor battery life.
• Changeable TPMS valves.
• 4 complete sensors and valves plus wireless display.
• 1 year Manufacturer's Warranty.
• Perfect for track days - no more guessing tyre pressures and a high visibility display.

Benefits of using the Tyre Pressure Monitoring System

• No need to check tyre pressures saving you time.
• Better fuel consumption saving you money.
• Normal tyre wear saving you money.
• Reduced chance of premature tyre failure saving you time and money.
• Less risk of accidents, saving lives.

The Tyre Pressure Monitoring System is available at just £180.00 FULLY FITTED at your nearest National Tyres and Autocare branch.

The TPMS system was voted Top Product by Channel Five's The Gadget Show's Focus Group - as seen in this video in Nov '08.

WHAT SETTINGS SHOULD THE PRESSURES BE SET TO?

The system can set the LO level from 20 psi to 40 psi. We recommend that the LO level should be 5 psi below the manufacturer's recommended pressure. If a car's pressures are different front to rear, set the LO level to 4 psi below the lower pressure. The system can set the HI level from 30 psi to 60 psi. Generally tyre pressures can increase by between 4psi and 8 psi on a reasonable length drive so we recommend that the HI level should be 10 psi above the manufacturer's recommended pressure. If a car's pressures are different front to rear, set the HI level to 10 psi above the higher pressure.

HISTORY OF PNEUMATIC TYRES

John Boyd Dunlop is credited with inventing the first practical pneumatic tyre, although this wasn't used on automobiles until 1895, by Andre and Edouard Michelin - until this point, solid rubber tyres were still used, so although you didn't need to check your pressure in those days, you certainly had a bumpier ride!

This article is written by expert Chris J Dutton who has 17 years industry experience and writes news, content and press releases. If you would like to make contact with Chris then you can do so at Email and also see Chris's Google+ profile or contact customer services for any other query.