Difficult to pinpoint the cause from the tattered remains; curiously, I was watching Fifth Gear a few days ago and they did a feature on run-flat tyres. (Any excuse to watch VBH!). The gist was that typically a nail or similar object will be picked up and take a long time to work its way through; when it finally does, the deflation at speed will cause the empty carcass to generate phenominal amounts of heat and it's this that causes the sidewalls to fail.
This is borne out by the vulcanized tatters; at first I did wonder about the manufacture - still have the Marangonis on the rear - but on reflection, the fact that the remains stayed on the rim for several hundred yards was what made it possible to pull over safely, albeit in a series of little swerves as the remains shifted from side to side whenever I touched the brakes.
Not sure whether I actually remembered the instuctor's injunction not to unsettle the car; probably just luck. And lucky it was a rear and not a front
tyre. And there were no trucks in the way.
In fact I may be driving on the assumption that I've used up my fair share of luck for quite some time.
