Tread Depth Gauge

The legal minimum in the EU is 1.6 mm for cars. Measure at several points across the tyre. Wear indicators in the grooves give a quick check. Many experts recommend replacing summer tyres before they reach the legal minimum because wet grip falls significantly in the last millimetres. Some countries have higher minimums for winter tyres in winter conditions. A coin test is a rough check, but a gauge gives an exact value for comparing tyres.

A pin extends into the groove and shows the depth on a scale.

Uneven readings point to alignment or pressure problems. Winter tyres lose grip in snow well before the legal limit.