Tread wear indicators - Cross ribs evenly spaced around the circumference of the tire in the main longitudinal tread grooves which become level with the tread surface when the remaining tread depth is down to approx. 1.6mm. Continental acknowledges that 1.6 mm (2/32”) is the most widely accepted minimum tread depth standard at which tires should be removed from service.
This standard has been adopted as a legal regulation by many of the world’s national transportation authorities.
Continental recommends the following tread depths for tire replacement:
summer tires 3 mm
winter tires 4 mm
Continental has introduced the “Summer Treadwear Indicator” in various summer tire lines. The Summer TWI informs the driver when the remaining tire tread depth is 3 mm. Once the tread is worn down to 3mm, the Summer Indicator becomes level with the surface of the tread pattern, indicating that there is a significant reduction in the wet grip performance. Continental recommends changing summer tires at 3 mm remaining tread depth, as this is this the optimum compromise between safety in the wet and economics.
As the tread depth governs many of the winter tires‘ properties. Continental recommends to change winter tires for winter grip at a tread depth of 4 mm. Once the tread is worn down to 4mm, the Winter Indicator becomes level with the surface of the tread pattern, indicating that the tire has reached its‘ limit of winter suitability.