Question about tire and rim sizes

[Crambo]

I've got a 2015 Tradesman 4x4 and I ordered some new 18x9 rims for it. The stock tires are 275/70/18 and from what I've read, these are recommended for a more narrow rim. Can this size tire be mounted on a wider rim and if so what happens? I to sure how wide the factory wheels are on my truck.

 

[16919]

Im in the exact same boat. It seems like some people say its ok and some say it isnt. Im trying to decide if its worth trying to swap the stock tires to my new 18x9's or get new tires and try and off set the cost by selling the stock wheels/tires? All opinions welcome...

 

[BigPapa]

From what I find approved width for the LT275/70R-18 is 7"-8.5".