How to Use A Tire Tread Gauge?

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How to Use A Tire Tread Gauge?

Incorrect air pressure, vehicle alignment, loose or worn parts, driving conditions, load, etc, can cause rapid or uneven tire wear. An accurate tread depth gauge can detect developing wear patterns earlier than simply looking at the tread. This often allows the cause to be identified and corrected before excessive or irregular tread wear ruins the tire.

Minimum tread depth should be 2.5mm or about 3/32.  Any grove under this minimum depth is designated unsafe.  The tire or tires should be replaced.  At this depth, your vehicle’s tires will not adequately evacuate water and snow.  The result is hydroplaning, sliding, and decrease braking efficiency.

While coins can be used to estimate remaining tread depth as a tire approaches the end of its useful life, the established method of measuring remaining tread depth in Canada is with a gauge that reads in millimeters (or in 32nds of an inch). Some tire tread depth gauges measure up to 25-26mm (or 32/32nds) since almost all passenger car and light truck tires begin with less than one inch of tread depth.

To use a tread depth gauge, follow the steps below.


  • Step 1:Confirm which measuring scale you are using. Some tread depth gauges measure in 32nds of an inch (left), while others measure in both 32nds of an inch and millimeters (right).


  • Step 2:Push the tread depth gauge against a hard, flat surface to confirm it “zeros out” when fully compressed.


  • Step 3:Push the measuring scale into the gauge as far as it will go.


  • Step 4:Place the probe into the center of a circumferential tire groove and push down on the gauge’s base.


  • Step 5:Do not place the probe on the molded tread wear indicators or on any raised surfaces of the tread design.


  • Step 6:Carefully remove gauge by holding its barrel (without touching the probe) and confirm the tread depth reading.


  • Step 7:Place the probe into additional locations around the central circumferential tire groove at lease 15 inches apart and repeat.


  • Step 8:Place the probe into the inner and outer circumferential grooves and repeat.


  • Step 9:Average all readings.


  • Step 10:Identify the percentage of tire wear by confirming the tire’s original/new tread depth in its specs compared to the remaining tread depth just measured.