Should you change summer tyres if their tread depth is 2.7 mm?
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“Consider that the tread depth should be at least 3 mm to provide good friction on a wet road.” (Swedish Transport Agency)
The tread depth of a new tyre is around 8–9 mm. 2.7 mm is therefore rather shallow. In normal road conditions, a tyre with a 2.7 mm tread depth will not differ significantly from a new one, but in wet conditions, the risk of aquaplaning increases as the water is not pushed aside as well by the pattern of the tyre.
But the law only requires 1.6 mm?
– That is true, but this question is not asking about the smallest tread depth possible, but the recommended one. The grip deterioration happens gradually; it is not that a tyre with a tread depth of 1.61 mm is really good and one with 1.59 mm is really bad. They probably provide the same amount of grip, but the line has to be drawn somewhere.
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