Tread Depth, Measuring
For this, pay attention to the running surface depth differences. Refer to PERMITTED DIFFERENCES IN TREAD DEPTH .
When measuring tread depth, take measurements in the main grooves.
Do not take measurements at the tread wear indicator.
Tread depth of a tire must be measured in the main grooves at the points showing the most wear. The positions of the tread wear indicators are marked along the tire shoulder.
In place of "TWI", there may also be a "Δ" or "company emblem".
The TWI protrusions are 1.6 mm tall. This is the minimum tread depth legally prescribed in Germany.
Different values may apply in other countries.
Tread Wear Indicators (TWI) must not be included in the measurement. The deepest point of the groove must be used for the measurement.
A - Tread Wear Indicators in Main Tread Grooves
B - Main Grooves with Tread Wear Indicators -arrows-