What's the biggest tire you can put on a ford ranger? Width, height, etc..
I got 33'sX10.5X16 on mine but I had to get a 3 inch lift to get the tires to fit. Also have a 4.0 engine, it has no problems, but I don't know if you can go that big with a 3.0 engine and definitely can't go that big with a 4 cylinder.
According to what I've read 31x10.5x15 is about the biggest tire for Ford Ranger. It fits well without any modification of the truck. This may vary depending on the model of your Ford Ranger