So I like the mileage our 2012 D/A gets with and without towing. We are looking at the Ford F350 with 3.55 rear end and wondering if the mileage is comparable or not.
Since Ford chooses the tire size that goes with the wheels they offer, it doesn't matter how you describe it. Ford doesn't "offer" different gear ratios, they install the ratio that gets the end result they want. In the case of the F250 and F350 SRW models only the snow plow package will get you a different RPM at any given road speed.