Your tyres are what sits between you and the road. Looking after your tyres will not only save you money – on tyres and also on fuel – but they are an essential safety feature of your car. Tyre replacements can often be unexpected and expensive so it makes sense to take care of them.
Taking care of your tyres
Keep your tyres inflated correctly. Inflate tyres to your manufacturers recommendations and recheck once a month. The recommended tyre pressure is usually recorded on the pillar of the driver’s door. Under inflated tyres result in increased road friction, meaning that the tyres will wear faster and require move fuel to run the car.
All four tyres should be of the same tread pattern. Ideally, the spare tyre should be identical. If fitting new tyres, put them on the same axle – preferably the rear. Regularly check the tread depth and tyre pressures (including the spare).
Match your tyres
Driving with mismatched tyres is dangerous. Among other warrant of fitness requirements, tyres on the same axle must be of the same tread pattern. However, there is no legal requirement for tyres on all axles to be the same tread, even though NZTA agrees that fitting four identical tyres (preferably summer) provides the best grip.
Know when to replace your tyres
Accurately predicting the serviceable life of any specific tyre in advance is not possible. A tyre is composed of various materials and rubber compounds that affect its performance. Its performance also depends upon many other factors such as weather, storage conditions, and conditions of use. That’s why we strongly encourage drivers to regularly inspect their tyres to identify anything which means that the tyre needs to be removed from service.
As well as regular tyre inspections and maintenance, drivers should:
- Have tyres that have been in use for five years or more inspected by a specialist at least annually.
- Follow the vehicle manufacturer’s tyre replacement recommendation.
- Replace tyres still in service ten years or more from the date of manufacture with new tyres, even if they appear serviceable and even if they have not reached the legal wear limit
Check your tyre pressure every month
Correct tyre pressure reduces the risk of losing control of your vehicle. It also protects your tyres from premature wear and irreversible damage to the internal construction. Tyre pressure can drop due to small perforations, the natural escape of air through the tyre’s components, or even from a decrease in ambient temperatures. Check the pressure of your tyres, including your spare, monthly and before any long journey, preferably when your tyres are cold (not having run for at least 2 hours or having run for less than 2 miles at low speed). If they are not checked in this cold condition, add 4 to 5 PSI (0.3 bar) to the recommended pressure, but never deflate a hot tyre. It’s important to check the pressure once a month, because:
- Under or over inflation can reduce the life of your tyres, affect their performance and increase the risk of damage.
- Correct tyre pressure will even save fuel
The recommended tyre pressure can be found in the user manual of your vehicle, on a label on the door or door frame of the vehicle or on the inside of the fuel flap The recommended tyre pressure is NOT located on the tyre. The inflation pressure shown on the tyre sidewall is the maximum tyre inflation pressure.
Snow tyres are made with a softer rubber compound and deeper treads, designed to maintain grip in ice and snow. They can be distinguished by their deep square-patterned tread blocks with numerous fine blades. NZTA says the majority of Kiwi motorists have no need to use snow tyres – those who do drive in ice or snow should have them fitted to all four wheels and change them at the end of winter.
However, snow tyres must not be confused with all-season ‘mud and snow’ tyres (often marked with the letters ‘M+S’ on the sidewall), which are designed to perform safely in a wide range of summer and winter conditions and are commonly fitted to 4WD vehicles.
Check the tread pattern on all four wheels, and if any appear to be specialist snow tyres, arrange for these to be replaced with ordinary summer tyres. Have your car inspected immediately if you’ve ever experienced any loss of control, particularly if it’s a Japanese import.
New rules concerning the use of winter (or snow) tyres came into effect on 1 April 2010. The regulations prohibit mixing winter tyres with normal tyres on the same vehicle. As part of the WoF check, a vehicle will now fail if it has mixed tyres. A new minimum winter tyre tread depth of 4mm also applies, compared to 1.5mm for standard tyres.
The rule change follows several fatal accidents involving vehicles fitted with a mix of normal and winter tyres, and subsequent testing which showed that such combinations can result in different levels of grip on the front and rear axles, which can lead to a loss of control, particularly under emergency braking or in the wet.