both probably gone at the same time as you where doing miles on the motorway and they got some heat into them
I would have thought the tyres havnt been kept in the proper conditions, for one to go, maybe, but both at the same time seems strange.
Passenger side completely fell apart on inside and outside of the sidewall
Drivers side just lost all structure and the metal reinforcement frayed out of the sidewall, but it did still hold air...
This is their first significant motorway journey... never exceeded 65mph (probably didn't exceed 60)
They have previously done 1 hour plus journeys on A roads at the same sort of speeds.. and some semi enthusiastic driving on Norfolk B roads
I obviously can't know their 5 or 6 year storage before I got them.. but they show no signs of perishing or cracking both in feel and visually..
It just seems really alarming to me that they would fail so spectacularly whilst being used well within their limit of speed/weight. Regardless of age not being excessively over what is considered advisable I'd have thought any potential degradation would still be in a tolerance for tyres designed to do 100mph+ with hundreds of KG on them
Heat... might explain why the passenger side failed more significantly with the additional radiator heat nearby.. but it still feels a bit extreme to me... the weather wasn't really hot causing the tarmac to have any affect.
Either way it's really put me off any unknown brands of tyre