[Klewy]

Weight capacity can be critical. I once had to replace tyres on my caravan with a lower weight rating than the originals and they failed after a couple of thousand miles. If you consider the tyres you're talking about then you're dropping nearly half a ton in capacity compared to the correct spec tyres.

My maxim is never to mess with tyre specs, especially the weight carrying capacity. It's too late to learn the lesson if they blow out at motorway speeds, especially if the car is fully loaded, as next stop is the scenery