Difference between 4.30 & 3.55 gears
My 2011 F-350 has a 3.55 geared rear end. The new 2017 F-450 only comes with a 4.30 geared rear end. Basically the same engine (6.7 turbo diesel). Does that mean better or worse fuel consumption...
Forum Discussion
ShinerBock wrote:X 2
The formula for engine rpm is as follows:
(Axle Ratio x Vehicle Speed(in MPH) x Transmission Ratio of Selected Gear x 336.13) / Tire Diameter = Engine RPM
Just plug in the numbers and you get what rpm each rear gear ratio should be at a certain speed.
The worse fuel consumption depends on many variables, but yes when towing a shorter gear ratio(higher number) will generally have better fuel economy than a taller gear ratio(shorter number) when towing.
