Tyre SafetyMonday, April 9, 2018

Tyre tread depths and driving safety

Loss of vehicle control can occur when tyres with insufficient tread depth are used on wet roads. To avoid this possibility, all tyres must have sufficient tread depth.


What is the function of a tyre’s tread grooves?

The tyre’s tread grooves disperse water away from the tyre’s contact patch when roads are wet. Where tyres have insufficient tread depth, their ability to disperse water away from the tyre’s contact patch when roads are wet is compromised, which can cause the driver to lose control of their vehicle. The contact patch is where the rubber meets the road and is about the size of the palm of your hand. One palm per tyre!


Why is it essential to have tyres with sufficient tread depth?

When tyres have insufficient tread depth and can’t disperse water from the contact path they can become separated from the road surface. This is known as ‘aquaplaning’ and is very dangerous because the tyre cannot transmit steering, braking and necessary drive forces onto the road surface.

It is also a legal requirement for tyres to have a minimum tread depth of 1.5mm.

The tread depth of the tyre will determine how much the tyre’s contact patch is reduced in wet conditions and therefore the amount of grip the tyres can provide. When new, the tread depth of most passenger car tyres is close to 8.0mm. In Australia, for road worthy purposes, tyres with a tread depth 1.5 to 1.6mm are considered worn out.


How do I check the tread depth of my tyres?

All tyres have tread wear indicators moulded into the tread grooves. When worn down to these indicators on any part of the tyre, the tyre should be replaced.

When checking the indicators for signs of wear, be sure to examine the whole tread area, including inside the tyre’s tread.

Article supplier by Tyre Power Mackay