Hi I recently upgraded my truck to an 09 f350 CCLB Lariat Diesel with leveling kit. It already has aftermarket 20" wheels but the tires are pretty well worn and I'm hoping to get a new set by the winter. I currently have 275/65/r20 a/t on but I want something a little bigger and wider. Any suggestions for how big I could go without rubbing??? Thanks for any help!!!