How do I know if my tires are worn out?

All tires come with tread wear indicators. These are small bands of rubber between the tread blocks of a tire. When the tread is worn down to the level of the indicator, it's time to change your tires.

A tread depth of three mm is about the limit for all-season and performance tires. Winter tires are considered worn out when the tread depth dips below six mm.

Another sign that your tires are at the end of their useful lives: cracks appear in the rubber. The tires can no longer be considered safe to use.

Source: http://www.cbc.ca/news/story/2008/11/18/f-snowtires.html

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