Tyres are vulnerable to wear and tear with the passage of time. After a certain period of time, they have to be replaced. The key factors in determining the wear and tear of a tyre are measuring the tread depth and tread width. These factors have been discussed briefly in this document.

1. How to Check Tyre Wear
Being able to measure the tread depth and width of your tyres and knowing at
what depth they should be replaced is very import to the safety of your vehicle.
Measuring Tread Depth
Tread depth is the vertical measurement between the top of the tread and the
bottom of the tyre’s deepest groove. In Australia, the law requires a minimum of
1.5 mm tread depth across the face of the tread normally in contact with the
road.
To help gauge the wear, car tyres have tread wear indicator bars moulded across
the tread at regular spacing’s around the tyre. When the tread wears down to the
legal limit, the wear bar will be level with the tread blocks. The letters TWI (Tread
Wear Indicator) are often moulded into the edge of the tyre tread where the wear
bars are located.
The average new tyres used on cars typically start with 8mm to 9mm of original
tread depth. Winter / snow tyres and light truck tyres are usually deeper. In the
case of light trucks the tread depth depends on the tyre’s tread type; Highway Rib,
Highway All-Season, Off-Road All-Season Terrain or Off-Road Maximum Traction.
Measuring Tread Width
The tread width of a tyre is the measurement between the outer and inner edges
of a new tyre’s tread design. This is usually about the width of the tread that
comes in direct contact with the road. Unfortunately, measuring the width of a
tyre’s tread isn’t as simple as laying a ruler across the tread.
It’s relatively easy to measure the square-shouldered designs used on most winter
and off-road light truck tyres, however, it’s much more difficult to measure the
tread width on a tyre that has multiple radiuses and rounded shoulders which are
featured on most passenger and performance tyres.
Unfortunately there isn’t an industry standard that requires a single procedure for
how to measure tyre tread widths. Since manufacturers are able to use different

2. methods, their published tread widths are only meaningful when compared to
other tyres measured the exact same way.
This makes it difficult to compare tread widths of one tyre brand to another, most
tyre manufacturers have simply chosen to eliminate tread width dimensions from
their brochures and websites.
There isn’t a legal limit for tyre width but it’s still good to know how to measure it
because the wider the tyre the better it handles cornering, especially at high
speeds and also in bad weather conditions. Tread depth is the most important
measurement to know and check regularly.
Presented By
www.tyreempire.com.au