Check Tyre Tread at Home with the Coin Test

Checking tyre tread regularly is important to ensure safe traction and braking. Australians can easily monitor tread depth at home using the simple coin test. Here's how to perform it and what the measurements mean.

Why Measure Tread Depth?

As tyres wear down, the tread pattern grooves become shallower. Thinning tread directly reduces wet weather grip. It also makes aquaplaning more likely, where a film of water completely separates the tyre from the road.

Legal minimum tread depth in most Australian states is 1.5mm for passenger vehicles. However, performance drops well before reaching this limit. Replace tyres when tread depth nears 3mm to maintain control.

Measuring tread periodically ensures you remain above safe levels and can replace tyres proactively. DIY tread checks also indicate if tyre rotation is needed to even out wear.

Performing the Coin Test

This straightforward technique only requires a 20 cent coin. Simply:

  • Take the coin and insert it into the main grooves across tyre width, perpendicular to the direction of tread. Select a groove around the tyre midline.
  • Check that the coin's outer band is not visible when fully inserted. It should be obscured by surrounding tread.
  • Repeat in grooves across all tyre sections - middle, inner and outer edges.
  • Compare coin insertion and visibility on front vs rear tyres. Uneven wear indicates rotation is overdue.

As long as the coin top stays covered, there is adequate legal and functional tread depth. If the coin is visible or loose, it’s time to consider replacement.

What Depth Does the Coin Show?

Most 20 cent coins are 2mm thick on the wide outer band. So if the band remains hidden by tread when inserted, minimum depth is at least 2mm.

The normal minting tolerance means depth could be between 1.5-2mm. Either way, it confirms safe legal tread is present if the coin insert is snug.

Conversely, any coin visibility indicates depth is less than 2mm at that test point. Partial band exposure suggests marginal tread around 1.5mm. Full outer band visibly exposed equals less than the legal 1.5mm limit.

Other DIY Tread Depth Checks

For a more precise measurement, use an inexpensive tread depth gauge tool. Insert it straight into grooves at multiple points around the tyre.

Some tyres have wear indicator bars molded between tread blocks. These become visible as tread wears down toward the minimum 1.5mm level. Look for tire wear bar indicators inside the main grooves.

Mark a wear bar with chalk when visible. That makes it easy to check after driving if it wears down further, meaning replacement time.

DIY tread checks identify both legal limits and the recommended 3mm minimum for staying safe in Australian conditions. Be proactive for confidence on wet roads.

Partner with Safety Experts

In addition to DIY checks, have your tyre treads inspected periodically by the experts at Darra Tyres on 07 33753366. Their qualified technicians use precision tools to measure tread depth across the tyres and identify any uneven wear. This helps maximize tyre life through timely rotation and replacement. Don't lose traction - stay safe in wet weather by monitoring your tread.

About the Author

Brett is Darra Founder Kevin's son. He grew up over the past 30 years of owning Darra and before that his whole life of Kevin being around trucks, transport and everything mechanical. So whilst he is not one to pick up the tools, its certainly been a big part of his life since Kevin's 'right-of-passage' was to get him to strip an old Holden straight-six 202 engine and put it back together. These days his time is spent with his 4 kids between UK, Singapore and Australia where he has a variety of businesses.