Any repairs shall be done by a specially trained person who knows proper repair and inspection procedure. Never repair tyres worn below the tread wear indicators (2/32nds of an inch of tread remaining depth). Punctures through the tread can be repaired if they are not too large, but punctures to the sidewall should not be repaired at any time. Tyre’s internal structural damage may occur during the service, even if a tyre was properly repaired. Even properly repaired tyres often have to be removed from service because the repaired damage later develops into a more extensive damage.