Be sure to try the steering on overseer lock and then drive onto something like a house brick. I tried 255/55/18 and all seemed ok until I tried to simulate an off road situation as above. The suspension travel isn't parallel and so as the wheel went up it goes in at the top too. Even with this tyre size it would have ripped the brake pipes to bits.I went in for 255/50/19 but my tyre guy worked out that 235/55/19 will suit better. I'm not convinced, but he's been doing this for decades, so I will go with his suggestion first.
I've used the same shop for years, and spend a lot of money with him, between myself, my business and family, so i'm lucky that I get the option to test fit these things first. I really didn't want to run the 19s through the winter, but this is something i'm trying out before I have no option but to buy more wheels. (and if I do, they will be the 18" Amarok steels)
Had 235/55/18 AT3s fitted and they are the best I've ever had.
Will be interested in knowing the result of the 19s