Factory 3.92 Gears. MPG changes with 34-35s?

[LoAndBehold]

2021 4x4 EcoDiesel with 3.92 gearing. I don't tow much at all and do tons of freeway driving. Yeah...the truck was the only one I could get my hands on otherwise I'd have opted for different gearing. If I go with a 34" tire I'll be at about 3.67, and with a 35" I'll be at 3.58. I'm thinking the offset of larger tires with more rolling resistance will be offset (or more than offset) by decrease in effective gearing.

Question: Anyone have experience with MPG on when increasing tire size to 34-35" tires on a RAM with 3.92 Gearing?

 

[paulmarsh22]

After my 5 inch lift and 35x12.5r22 Toyo AT3 tires, I get roughly 13mpg city and 17mpg highway. It was quite a drop from stock but I also haven't recalibrated my speedo yet so not sure if that plays a role as others have stated.

 

[tidefan1967]

With the Ecodiesel you probably won’t even notice a drop in fuel economy, maybe 1 MPG. Nothing like the Hemi for sure.

 

[LoAndBehold]

Bump. Seriously...no one with an EcoDiesel has increased tire size and has a MPG report?!

 

[Whoa_Ram]

Bump. Seriously...no one with an EcoDiesel has increased tire size and has a MPG report?!

From the multiple posts I've read up and the very few people that have EcoDiesel's and put 35's they usually claim to lose 1-2mpg's all around. Not bad in my opinion since you guys already get anywhere from 22-28mpg's haha.

 

[hutchman]

I have a 2021 Ecodiesel with 3.92s and 295/70-18s.....not quite a 35" tire but close. The first 6000 miles I averaged 24.5 hand calc'd. The first 2 tanks with the new tires and wheels I've averaged 23 mpg corrected for tire size. I lost about 1.5 mpg....well worth the change for me.