We seal a tread puncture with a plug-patch or a patch from inside the tyre, not a string plug from outside. The repair stays airtight and holds at speed.
Sidewall cuts are harder: the sidewall flexes all the time, so we restore them with hot vulcanizing and a cord patch. It's a rare service and often saves an expensive tyre.
We assess the damage before any repair. If a tyre is unsafe to fix, we tell you straight.