Ring Automotive is the industry leader in at-home tyre care specialising in easy to use, accurate and effective tyre inflators (also called air compressors).

Part 1

General top tips about inflating your vehicle tyres

• How often should I check my tyre pressures?

  Once a month

  The reason you need to keep checking is because tyres do lose air-pressure over time, sometimes 1 or 2psi per month, and factors such as temperature can also exacerbate the situation. If you inflate your tyres to their correct level on a hot day, the air-pressure inside the tyre will reduce if the weather suddenly gets cold. Month to month this typically isn’t an issue, but it can be a major factor if you’re entering Winter and haven’t checked your tyre pressures since the Summer.

  Visual checks are not enough - What we found most alarming about this exercise is just how little the tyre changed visually as the pressure dropped. Using the recommended 32psi as a comparison, there was virtually no visual difference when the tyre was deflated to 24psi – that’s almost 30% under the recommended level. Amazingly, the tyre continued to hold its shape right down to around 14psi – at which point the bottom began to look ‘flat’ visually. It progressively got worse down to 8psi, at which point we concluded the test.

  So what can we learn from this? Just because the tyres on your car look properly inflated, doesn’t mean they actually are. Failing to properly check the air-pressure in your tyres over extended periods of time mean that your tyres could drop to less than half their recommended air-pressure level before you’ll see a visual difference.

  This could easily put the lives of you and your family at risk

• When should I check my tyre pressures?

  When tyres are cold. If you drive before inflating you will get an inaccurate reading. As the air moves within the tyre, it will heat up and so increase the pressure.

• Why is tyre pressure important

  Correct tyre pressure is vital for safety, the environment and helping you to save money.

  Safety – Correct inflation provides optimum road handling

  Environment – Tyres underinflated by 14PSI / 1 BAR increase the rolling resistance and therefore required more fuel to be burnt so producing more CO2.

  Money Saving – By having correctly inflated tyres means less fuel burnt and less wear and tear on the products.

• Why do I need to check my pressures when I have a TPMS system?

  Tyres can be up to 20% underinflated by the time TPMS warnings come on and this can mean tyres are already at a dangerously low pressure.

• When should I change my tyre pressures?

  Tyre pressures should be changed when the load of the vehicle is altered. Car manufacturers provide pressure settings for normal and max/heavy loads.

  Your tyres were correctly inflated to the standard “un-laden” pressure values before you set off on your holiday. By the time you’ve added a few hundred extra kilograms of luggage, bikes, equipment and general stuff, as well perhaps as the dogs, a couple of adults and some kids, you’ll be looking at around an additional half tonne of additional weight, perhaps even more.

  That extra weight changes things dramatically for your tyres. Why? Because the rubber compounds are slightly flexible, the tyres expand and – instead of being correctly inflated – they start behaving as if they’re under-inflated.

  Motorists need to change the tyre pressure in accordance to these reference charts to ensure the tyres are working optimally.

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TYRE PRESSURE PLACARDS EXPLAINED

1. Select your tyre from the list. These numbers and letters make up the size and width (among other things) of your tyres. Look around the outer side wall of one of your tyres. You will see numbers formatted similar to those on the label diagram. Use a pen and paper to write down your tyre type. Most cars have the same front and rear tyres, though in some cases they may be different. Check both and front tyre to ensure they’re the same. If they are different, write down both types.
2. Compare your tyres to those on the sticker. Keep within the thick separating lines and move along to the symbols of people and luggage. Select the top section if your vehicle is light – up to three people in the car with light luggage, or the option under if you have a car full of passengers with a boot full of luggage.
3. This option is for the front tyres along with the corresponding list of numbers below.
4. This option is for the rear tyres along with the corresponding list of numbers below.
5. Bar and PSI are both units of pressure. If you are using a tyre pump on a petrol station forecourt as most drivers do, you will need to select either Bar or PSI pressure unit on the pump – it doesn’t matter which unit you use as long as the tyre pump supports it.
6. For the rear tyre, if you are using PSI, use the amount of pressure on the list that has your tyre type (within the thick lines) and follow the option along the lighter or heavier load.
7. For the rear tyre, if you are using BAR, use the amount of pressure on the list that has your tyre type (within the thick lines) and follow the option along the lighter or heavier load.
8. For the front tyre, if you are using PSI, use the amount of pressure on the list that has your tyre type (within the thick lines) and follow the option along for either the lighter or heavier load.
9. For the front tyre, if you are using BAR, use the amount of pressure on the list that has your tyre type (within the thick lines) and follow the option along for either the lighter or heavier load.

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NUMBERS ON A TYRE EXPLAINED

• AWidth of tyre in millimetres
• BProfile height of a tyre sidewall as a percentage of the width
• CThe diameter of the wheels inner rim in inches
• DLoad index indicates the maximum load a tyre can carry
• EIndicates the maximum speed for the tyre
• FThe model name of the tyre. Unique to each manufacturer
• GMaximum load that the tyre is designed tyo carry (in both kg and lbs)
• HMaximum pressure that the tyre is designed to be inflated to (in both bar and psi)
• IBrand name of the manufacturer

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PRESSURE MEASURES

• PSI UK measurement – Pressure Per Square Inch
• BAR Standard in EU – Term for atmospheric pressure measured in 1Kg of per square centimetre
• Kpa KiloPascal - 1 Newton per Square Meter

• Why are the pressures on my front and rear tyres different ?

  Tyre pressures are normally higher in the front than the rear, to compensate for the extra weight of the engine and transmission, especially on front-wheel-drive cars.

  Some makers run lower pressures in the front, mainly to improve tyre wear on rear-wheel-drive cars. Rear-drive cars generally have less weight over the front tyres

  ***The pressures of the 2 front wheels or 2 rear wheels should always be the same ***

• Where can you find tyre pressure values?

  Look up the tyre pressure values in your car’s user manual. They’re often also printed on the inside of your fuel cap, and inside the driver’s door. You’ll typically find two figures; one’s for normal ‘un-laden’ use, and the other – a higher figure – is for when your car is laden.