best rpm 870

[Rawze]

(05-03-2025 )mikkhh Wrote:  ...
How much is the fuel consumption with gear lower revs 1600-1800 cruising at 55mph vs 65mph and 1400rpm.
...

rpm range vs fuel economy at the same exact speed is a mis-nomer unloess the truck is absoutely bobtail with zero load on it.. which is not the case on a truck that has to haul freight.

as soon as you put any kind of load.. even light load on the truck.. the rpm make absolutely ZERO difference unless your running 2,000+ or something unnecessary.

A fine example is my own truck. I run 55-58 mph everywhere and ... I easily get in the 8-9mpg range all day long with fully loaded 80,000 lbs, running 1750 rpm, a gear down. Matter of fact, it gets slightly lower mpg if I do go up a gear and lug it below 1500 or so when loaded.

This subject has been discussed on here before many times...

rpm range vs. gearing...
https://rawze.com/forums/showthread.php?...3#pid17353

An article on Hyper-miling (for extreme fuel saving nuts like me)...
https://rawze.com/forums/showthread.php?...8#pid24378

other related posts...
https://rawze.com/forums/showthread.php?...6#pid17356