- Joined
- Feb 25, 2011
- Posts
- 1,047
- Reaction score
- 559
- Location
- South Dakota
- Ram Year
- 2020
- Engine
- 5.7L Hemi V8
An an aside, Scientifically proven dCt that a tonneau doesn't at all help with mileage. In fact it hurts.
I have ready studies that have gone both ways. Consumer Reports reported that a tonneau hurt MPG worse than with the tailgate down (and we all know how much faith we can put into some Consumer Reports "tests" sometimes), while SEMA reports that a tonneau decreases drag by 4.2-7.8%. Mythbusters was right in the middle, saying tonneau covers didn't hurt or help, but were better than having the tailgate down.
It supposedly also depends on your truck configuration/trim (long box vs short box, single cab vs crew cab, etc. etc.), so real conclusive testing would be very hard to do.
But back to the topic at hand... if towing any big loads regularly, go 3.92s. If towing mild loads (or a medium load every once in a while), and you want the best MPG in-between (when load-less), go 3.21s. If you plan on going bigger tires, 3.92s would probably be better, although its not the end of the world if you don't.