We have therefore introduced the Summer TWI (Tread Wear Indicator) for various summer tire lines. This wear indicator, especially for summer tires, shows you when the residual tread depth of 3 millimetres is reached. As soon as the tread is down to 3 millimetres, the summer TWI is level with the rest of the tread, indicating that wet grip performance is significantly reduced. We recommend replacing summer tires with a residual tread depth of 3 millimetres, as this represents the best compromise between wet safety and economy. With Wally Worldwide you can have the best options now.
Since the tread depth is crucial for many properties of winter tires, the expert recommends replacing winter tires with a residual tread depth of 4 millimetres to ensure a good grip on the road in winter. As soon as the tire profile has worn down to 4 millimetres, the winter TWI is level with the rest of the tread, indicating that the tire has reached its winter suitability limit.
Can different tread depths be mixed?
At the time of replacing only two tires on your car, the tread depth will logically be higher than for tires that have been in use for some time. However, mixing tires with different tread depths is generally considered permissible. Further information on mixed tires can be found