Ryan124235

I have a 2010 F150 FX4 that I'm looking to get rims and tires for but am not sure what offset to achive my wants. I have the stock rims and tires on it now. 275/65/18s with stock offset (+44 from what I research). I am looking for 20" rims, and I want the tires to stick out of the fenders. I was thinking about a -12 offset to get the tires sticking out about 2 inches. Thats what im lookong for but is that correct? Also I want to get a more aggressive tires for it and a bit wider, but I would like to try to get away without a lift or level.
Any ideas or personal experiences?