Remaining tread depth

What are tread wear indicators (TWI’s)?

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.

What is a summer Tread Wear Indicator? 

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.

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