Tire size in an "03" crew cab

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Hey all; You have probably already had this asked numerous times, sorry I cant find it in any archives. I am looking to get new rubber in my truck and was thinking about getting a larger, or wider size than the stock 235/75/15 size in this truck. Has anyone got this year/model truck that has done this? I was thinking about 235/70/15 or is there a 245/75/15. Its a 4x4 and I do a bit of off roading with it so I dont want any rubbing/turning issues.
Thanx