when you repair a tyre with a patch from the inside you are only closing the hole from the inside, travelling at 70mph in the rain will force water up the hole which was left from the nail/screw and put constant pressure on the patch, also water will ingress through the tyre and make the steel belt rusty, i must admit these plugs have been around for sometime, i used the in the 80s and had no probs, there is a mushroom type plug called stopngo and it is a better solution, .Yes your local tyre fitter will repair your tyre with the conti repair but what about if you are elsewhere,. i rang Kwikfit and National tyres and they wont touch them once you put in the liquid even though when i told the that i had contacted conti about this, they still refused. It is a dilemma that we shouldnt have to haver, Ford should put spare wheels in this vehicle