Rear-End Gear Ratios

[Junjun88]

(08-05-2017 )marek4792 Wrote:  

(08-04-2017 )Rawze Wrote:  Sounds to me like your trying to gear it around your bad driving habits. 6 mpg totally sucks and 70 mph beats the S$iut out of the truck.

Well I mean you aren't wrong I like to run the speed limit and sometimes schedules dictate that. I do see where you are coming from though with the wear and tear though. It probably would be cheaper for me to do just to replace it with another 3.42 which the truck came with and then the power divider before it fails when I get back home.

I mean lets say I drove 55 like you do with 3.42 it would put me around 1134 rpm and if I dropped a half gear (13 Speed) it would put me around 1335 rpm which you say is low for a Cummins especially under torque which is why I tend to drive closer to 65 in those 60-55 states just because I'm not geared for those states (blame the factory) but 3.55 would put me at a disadvantage when it comes to cruising on the 70+ states when I need to get it there yesterday.

I drove an older volvo with a CM570 with 3.58s I think and I was surprised how well the mpg was at 70 mph so its not outta the question that 3.55-58s are pretty good I'm just trying go weigh my options here considering the situation I'm in at the moment.

Thats what i was also wondering i have 11r24.5 3.55 rears and at 65mph rpms are at 1350 which i think is a little low but for some reason thats where i get the best mpg what would you guys recommend no less than 1400 rpm???

[amermextrucker]

I have a CM2350 is driving it at 1800 RPMS loaded or MT safe? At 1800 im at 64 mph. In 10th at 1500 im at 73mph . Too fast for me.
3.36 rears.

[Rawze]

(09-17-2021 )amermextrucker Wrote:  I have a CM2350 is driving it at 1800 RPMS loaded or MT safe? At 1800 im at 64 mph. In 10th at 1500 im at 73mph . Too fast for me.
3.36 rears.

that's a terrible rear end ratio.