Tyre Pressure Guide
Tyre Pressure is the measure of how much air there is inside your tyres.
It is essential to your tyre's - and vehicle's - well being because it is the air that is carrying the bulk of your car's load - not just the tyre itself. Tyres need to be filled with a prescribed amount of air to propel as well as stop your vehicle.
Tyre Pressure is measured in "psi" or pounds per square inch and each tyre should have the correct amount of air within for it to work properly.
Every driver has the responsibility to ensure the correct tyre pressure levels. You can check on your tyres at home using a handy, personal use, electronic tyre pressure gauge or simply by visiting the nearest petrol station where you can get it done for free.
However, because of our hectic and busy lifestyles, let's admit it - despite our best efforts to schedule inspections regularly, we sometimes forget and end up not paying attention to our tyres.
Having the wrong tyre pressure in your tyres is highly dangerous, especially when out on the road. Not only do you risk your own life, but that of your passenger's and other motorists and pedestrians on the road.
Incorrect Tyre Pressure
When your tyres have the wrong tyre pressure measurement, it can comprise your car's stability, braking capabilities as well as lose fuel-efficiency.
Tyre Deflection is a serious tyre condition where your tyre gets deformed and bulges out at its contact patch - or the part of the tyre that has constant contact with the road - and on its sidewalls. This is caused by having the wrong amount of tyre pressure in your tyres.
When tyre pressure is high
When you have too much air in your tyres, causing the tyre pressure to shoot up, your tyres will suffer from weakened grip and traction.
It will cause your car to slip, bounce, slide and glide all over the road while the brakes won't be as quick and responsive.
Compromised grip and traction is a disaster waiting to happen, especially if you are travelling on a crowded highway at high speeds.
When tyre pressure is too low
When the pressure is too low, on the other hand, more of the tyre's surface and tread ends up on the road since your tyre will effectively be running flat.
The tyre will suffer from excessive deflection - more of the tyre flattens out, creating a more significant and somewhat off-shaped contact patch.
The bigger the contact patch increases the friction between the rolling tyre and the open road, causing the tyre surface to heat up.
Excessive heat will affect the tyre in the long run, leading to faster tread wear.
Lowered tyre pressure frequently causes blowouts as well since it can significantly damage the inside surface of the tyre.
What causes wrong tyre pressure?
1. Situations like tyre flexing, distortion and vehicle impacts can diminish a tyre's air pressure.
2. If your tyres have too much pressure, it is a case of too-much compressed air loaded into the tyre at the petrol or vehicle service station.
3. Low tyre pressure, on the other hand, can be due to various reasons. Small holes on the tread can leak air out, the valve might be broke and it just naturally happens over time. Tyres slowly but surely lose pressure every day through a process called 'permeation'.
4. Seasonal changes or altitude changes also create a rise or drop in tyre air pressure.
In general, tyres lose up to one or two kilopascals of air per month in cold weather and even more in warmer weather. For every 10 degrees of temperature change, tyre pressure needs to be adjusted by approximately 1 - 2 psi.
5. Overlooking the load capabilities of trucks and 4WDs is another factor that can cause wrong tyre pressure. Because they are so often and variably loaded, their proper inflation pressure needs to be determined by actual tyre loads which require weighing your vehicle.
Benefits of Correct Tyre Pressure
There are significant benefits to keeping the correct air pressure in your tyres: they last longer, save on fuel, your car's handling is enhanced, and accidents are prevented.
How often should you check your tyres air pressure?
You should check the pressure of your tyres twice a month.
We also recommended you get your tyre pressure checked before a long trip and when your tyres are cold and not directly after a long drive.
If you check the tyres right after a drive, the reading will be inaccurate.
Schedule Routine tyre air top-ups
It is probably wise to start thinking in terms of refilling your tyres with air just like you do your petrol tank with fuel. A good reminder and the recommended interval between top-ups is every second time you fill up at the tank.
Different pressure levels
Many vehicles usually have different optimum tyre pressure measurements for the front and back tyres, so remember to have this adjustment made or maintained.
Also, remember to have the pressure in your spare checked. The space-saver type spare requires a higher air pressure level, and it won't be of any help if the tyre pressure is low on the day you need it.
How much air does my tyre need?
The correct air pressure is in the vehicle owner's manual. Every car also has a placard or label built-in usually located on the driver's side door panel that lists the tyres correct and recommended inflation pressures. Sometimes this label or sticker is also displayed under the fuel cap, or in the glove box. The label will look similar to the image below.
The placard tells you the maximum vehicle load, the cold tyre pressures and the tyre size recommended by the vehicle manufacturer. Another valuable resource is the Tyre load rating guide, as well.
Maintaining one's correct tyre pressure is the responsibility of every driver.
It can truly spell the difference between life and death in critical driving situations.