Ditto that. Mine came stock with 225x75R15s. I was happy cause I was getting 19 in town and 24 on the highway. When they wore out, I went up to 235x75R15s. Mileage dropped to 17/20. That seemed like a huge drop for just one tire size so I checked it with GPS. The speedo was right on for the bigger tires. Sounds like they pulled the wool over the EPA eyes by not running the proper speedo gear for the factory tire size. I get no rubbing at all with that tire size ('99 XJ).
Anyway, regarding the AC comment I saw on one of the posts. My AC is on all the time. In the 5 years I've owned it, the AC has only been off once when I wanted to see if it made a mileage difference. It didn't. So, the AC went back on and has been on continuously ever since.