There is a member on here with a code orange 37 PP with 13.5 wides and is running a perch collar and he still had to trim quite a bit to make them fit. I don't know what his offset is.
Here is a quote from another thread.
"Hello! I picked up a raptor recently with 37x13.5 toyo mts on a +1 offset wheel. Truck has perch collars, but thats it. Took it offroading and it obviously rubbed like crazy, mainly in the rear though. Lost a fender bolt on one side."
"I am getting different wheels and tires, and I want to keep 37s but I do offroad the vehicle to full compression. What offset wheels do I need to be looking for? I am looking at the factory BFG KO2 37s as well from the gen 3. Or am I better of just taking it back to 35s if I am pushing the truck offroad?"