Best rpm for mpg?

[Cattletrkr]

A while back someone posted a link to Cummins' website that told you your engines "sweet spot". For every weight class from 10K to 50K, it said the optimum rpm was 2150. Then you're supposed to select a gearing/transmission combo that would put you at that rpm. The calculator did this for all of Cummins' engines I think.



I don't have the link anymore.

 

[FDrake]

I ran my 2004 Quadcab SRW long bed with the 5th wheel tailgate from Las Vegas to San Ramon in October, 2005. Averaged about 70MPH most of the way and for the total round trip of 1120 miles I got 20 MPG. I get about 15 MPG around town with the signals screwed up or about 17-18 if I can get all the green lights. On the open highways I get a good solid 20 MPG solo. I average about 12-13 MPG towing my 12,400# 5th wheel Alfa. I now have about 10,000 miles on the truck since new in Feb, 2004.

Frank