I have a 2019 T6 Caravel Executive on standard suspension for the type. Fitted 255/55R18 BFG AT2 on 18x 8 steel rims, not long after purchase from new without any issues. I live Off Road, literally, on a small holding West wales and the axles occasionally get flexed but no rubbing, close though! A little while back, going to an MOT Testing station along a poor C road , I hit a largish puddle after avoiding most of them or just slowing down or wadding through at a sensible speed for those unavoidable. . At MOT it was noticed and I was informed ,that I had lost some securing screws for the plastic wheel arch. He passed the vehicle as it was in his opinion only slight while only on full compression and lock, however it did not affect safety in his pinion, told me to sort it, which I did. It is a bit close at that size and set up, so not ideal. It does very much need much taller suspension for our usage which I will get soonish. I am not particularly interested in the aesthetics, only what practical for my purposes.
I think 8 inch width is the ideal fitment for that size tyre and 18" good for off-road usage for the Caravel. 17" rims will of course fit but the clearance between disc and rim is too close in my opinion on some farm land because of trash, sticks and mud, getting caught up between disc and rim. I have tried 17" that's why I know. Everything is a compromise!
The BFG AT2 is a very good tyre for purpose. It is extremely tough and takes a lot of rough abuse in its stride. Heavy though and expensive! Fairly good on road throughout autumn, winter and spring. No issues with tarmac friction, dry or wet. They give very good feedback so no nasty surprises and are 3Peaks Mud and Snow. I usually swap a some time around then, mainly to conserve them but this last year kept them on all year because of how wet the land was. Absolutely soaking.
If I was not living off-road and not doing that sort of thing I would just stick to All Season Tyres. For most, that would be best compromise then. They are not too bad on wet grass and tolerate off road use to a fashion. They would suite most people just going camping and careful of road use. Off-road tyres are very much tougher and of course have much greater tread patterns for greater traction where it counts but a bit of a waste and not as good on road. the more off-road driving one does the more likely a tyre will get damaged or even destroyed because ordinary road tyres are so flimsy by comparison.
Do not know anything about stretching tyres? Go too far from manufacturing recommended rim sizes, then surely that must be a risk and compromise to safety? Couldn't that be used against someone following a serious accident, especially is someone was seriously injured or worse? Not for me, I will just stay boring, dull and ear on the safe side.
