It used to be the head of a matchstick, now it's a 20 cent coin to check your tyre tread.
This week is Tyre Awareness Week, created as a partnership between government agencies, tyre specialists and industry experts.
Car owners should be checking their tyres once a month to ensure they have enough tread depth, the tyres are not damaged, and are at the correct air pressure.
As tyres are the source of contact between the car and the road, the condition of a car's tyres impacts on stopping distance, handling and fuel efficiency.
The law says tread has to be 1.5mm deep. Look for a triangle () or TWI (tread wear indicator) marking which appears in about six places around the side of the tyre. When the tread of the tyre is worn down to the level of the indicator, it needs replacing immediately. Another easy way to give your tread depth a quick check is to insert a 20c coin into the tread. The base of the number 20 is approximately 2mm from the edge of the coin, so if you can see the whole of the number, it's time to think about replacing your tyres.
To find your car's correct tyre pressure, check the inside of the driver's door, look in the vehicle manual or check out www.energywise.govt.nz/tools/tyre-pressure
For more information see www.tyresafety.org.nz which includes helpful hints and tips about tyres, a guide on how to check your tyre condition plus a chance to win four sets of tyres.