Punctures, aquaplaning, decreased road holding and braking performanceâ¦ that are some of the consequences with a worn tyre. Remember, the tread wear limit has been defined by European regulations, and the limit is 1,6 mm on the tread for summer tyres. >The famous and classical tread wear indicator This is the most common system that everybody knows; a 1,6 mm thick rubber bar embedded at the base of the longitudinal grooves. When the tread wears down to this level, the tyres lust be replaced. To easily locate the indicators it exist The TWI acronym (tread wear indicator), the brand logo (a small Bibendum for Michelin) or a triangle. >Numerical tread wear indicator This system is less known. It consists in engraving a tread wear scale featuring several numbers on the tread, corresponding to the tread. Nokian and Matador are using this system. >An interesting alternative Two Chinese designers have designed a tyre prototype that changes colour when the tread is worn. The inner part of the tyre is fluorescent orange. So, when the colour appears, the tread is worn,. Ingenious, but difficult to implement, according to our specialists! A tyre that changes colours is not for tomorrow >Depth gauge Tread wear indicators are a fast way of assessing the degree of tyre wear, but they do not have the precision of the small tool depth gauge. 20 pence test, intermediate tread wear indicatorsâ¦ read the full article at rezulteo How to measure tyre wear And how do you check tyre wear?