The most important part of your car is not the engine. It is your tyres with the right inflation pressure. The amount of air pressure in a car’s tyres greatly influences its performance and safety.
It’s the air pressure inside the tyre that carries the load. The effective load capacity is proportional to the tire air volume and the air pressure.
Effects of Underinflation
Under-inflation causes an uneven contact pressure at the tyre / road interface leading to the tyre wear rate increase at the tread shoulders. It also causes high stress points on the tyre.
- reduces the service life of a tyre, due to the rapid shoulder wear
- can cause internal damage due to stress points and heat build-up
- increases fuel consumption
- negatively impacts on handling
Effects of Overinflation
Overinflation causes the size of the contact patch with the road to be reduced, leading to the vehicle load being carried on the centre of the tread. This causes the tread to wear more quickly in the centre.
- Overinflation reduces the service life of a tyre, due to increased centre tread wear
- Overinflation also negatively impacts on handling due to the reduced contact with the road
Do not overstress your tyres.
- Running a tyre in an overload condition causes high stress in the tyre
- This results in lower tread mileage + casing service life and in severe cases premature tyre failure.
- Additionally fuel consumption is increased
Check your tyre pressure regularly
Tyre pressure must be checked with a quality air gauge as the inflation pressure cannot be accurately estimated through visual inspection.
Check tyre pressures regularly (when tyres are cold) and ensure they are set to the recommended level for your vehicle.
Recommended tyre pressures can be found :-
- in the vehicle handbook
- inside the petrol flap
- inside the door frame
Check tyre pressure:-
- once every two weeks
- (The same recommendation also applies for tyres filled with nitrogen)
- when tyres condition are cold
- including the spare tyre or emergency tyre
- before going on a long journey
- NEVER reduce air pressure when tyres are HOT from driving. It’s normal for tyre pressure to increase during driving.
Apart from proper air pressure maintenance there are other tyre conditions that require inspection that are important for both safety and performance.
TREAD PATTERN DEPTH
Tread pattern depth has a significant impact on a vehicle stopping distance on wet roads.
The lower the tread depth, the longer is the stopping distance. The rate of increase in stopping distance, accelerates in the second half of the tyre’s life.
DUNLOP recommends to seriously consider adopting a 3.0 mm tread depth threshold to change the tyres.
The legal tread depth limit is when the tyre tread has worn down to the level of its Tread Wear Indicator (TWI) which is 1.6 mm high found on the tread grooves.
- Maximize tyre’s tread life.
- Tyres should be rotated at regular intervals of 10,000 km.
- Always rebalance the tyre assembly whenever tyre rotation is carried out and also to readjust tyre pressure where necessary.
- It is important to visually check the condition of tyres on a regular basis.
- Lumps and bulges may indicate the tyre has been damaged internally. If there is any doubt as to the tyres condition then the tyre should be immediately removed from service until it has been checked by a suitably qualified tyre expert.
- Any cut to the tyre, which is deep enough to reach the internal structure renders the tyre unsafe. It should be replaced or where appropriate repaired.
- Tyres deteriorate with age and if cracking or crazing is present it may indicate that the rubber is perished and the structural integrity cannot be assured. The tyre should be immediately removed from service until it has been checked by a suitably qualified tyre expert and if there is any doubt replaced.
If you are in doubt about the condition of your tyres have them inspected by an expert.