When must a passenger-car tyre with deterioration incompatible with safe use be replaced?

Correct answer

When its condition prevents safe use even if sufficient tread remains.

When its condition makes use unsafe, even if tread remains and it is under five years old. Wear, damage and ageing need assessment; some punctures can be professionally repaired after evaluation and others cannot. There is no universal mandatory five-year replacement rule: Michelin recommends annual professional inspections after five years of use and precautionary replacement ten years after manufacture. Follow specific manufacturer instructions and replace earlier if damage or wear requires it.