Poor gas mileage

[timstites45]

Hello everyone I have a 2015 ram 2500. I’m running 35 inch tires. I wanna know if anybody else is getting 8 to 9 miles to the gallon. I spoke with another guy that said he’s getting 14 to 16 and he’s got a 2020 ram 2500 with the 6.4 hemi and I have the hemi also 6.4

 

[olyelr]

Pour? Haaaaa

You wont do as good of mileage as the ‘19 and newer ones with the 8 speed trans. Dont even bother comparing to them.

I have a ‘16 power wagon, and have gotten around 12 mpg for the last 130k miles since it was new. I think i squeaked 13mpg out of it once in its life, but never more. It does have 35’s on it, but the mileage didnt really get any worse.

You should be getting somewhere around 12 at least, unless you drive like a complete @$sh0le lol

 

[olyelr]

Nice rig by the way…its a twin to mine !

 

[Govtman]

Pour? Haaaaa

You wont do as good of mileage as the ‘19 and newer ones with the 8 speed trans. Dont even bother comparing to them.

I have a ‘16 power wagon, and have gotten around 12 mpg for the last 130k miles since it was new. I think i squeaked 13mpg out of it once in its life, but never more. It does have 35’s on it, but the mileage didnt really get any worse.

You should be getting somewhere around 12 at least, unless you drive like a complete @$sh0le lol

Can also take revs per mile for your tire vs. the factory size and see how much more % wise the larger tire covers. Say If it's 8% more you can add that % to your mileage.

 

[crash68]

I have a 2015 ram 2500. I’m running 35 inch tires.

Does the truck have the optional 4.10 gearing? Was the speedometer/odometer corrected for the new tire size?
As other have mentioned, don't try to compare to the newer version with the ZF 8spd. For comparison 1st gear of your transmission is equivalent to 2nd gear of the newer ZF 8spd. It also has two overdrive gears and 8th is taller than 6th in your transmission.

 

[olyelr]

Can also take revs per mile for your tire vs. the factory size and see how much more % wise the larger tire covers. Say If it's 8% more you can add that % to your mileage.

Not if you do what should be done, and reprogram the computer for the tire size so everything is back in sync. Including the shift points.

 

[olyelr]

Does the truck have the optional 4.10 gearing? Was the speedometer/odometer corrected for the new tire size?
As other have mentioned, don't try to compare to the newer version with the ZF 8spd. For comparison 1st gear of your transmission is equivalent to 2nd gear of the newer ZF 8spd. It also has two overdrive gears and 8th is taller than 6th in your transmission.

I see a winch in the front bumper, so guessing its a power wagon (4.10’s).

 

[Govtman]

Not if you do what should be done, and reprogram the computer for the tire size so everything is back in sync. Including the shift points.

For that size tire I would. I went from 33(275/60/20) to 34 (275/65/20) and it feels like the 1500 hemi should have had 34s from the start. Speedometer off by 1mph at 65.

 

[olyelr]

For that size tire I would. I went from 33(275/60/20) to 34 (275/65/20) and it feels like the 1500 hemi should have had 34s from the start. Speedometer off by 1mph at 65.

Yea when i went from the factory power wagon 285/70/17 (33’s) to the 35’s it was absolutely horrendous before i reprogrammed for the change. The shift points in the trans were so screwed up.

I still wanna regear to 4.88’s or 5.13’s so bad, just havnt done it yet.

If your speedo is off a bit, just change the tire size on the programmer a bit. Its been so long i cant remember, but i think i set mine to 34”to get the speedo dead accurate.

 

[Govtman]

Yea when i went from the factory power wagon 285/70/17 (33’s) to the 35’s it was absolutely horrendous before i reprogrammed for the change. The shift points in the trans were so screwed up.

I still wanna regear to 4.88’s or 5.13’s so bad, just havnt done it yet.

If your speedo is off a bit, just change the tire size on the programmer a bit. Its been so long i cant remember, but i think i set mine to 34”to get the speedo dead accurate.

I noticed with the factory size 33" it was off on 1 mile check, when I went to 305/55/20 33.5" on back the odometer was correct.

So odometer runs out sooner with factory size tires than it should. How convenient for the car mfg having vehicle run out of warranty before it should.

 

[timber dealer]

2021 power wagon 12 mpg going downhill with a tail wind

 

[Alamedasam]

Hello everyone I have a 2015 ram 2500. I’m running 35 inch tires. I wanna know if anybody else is getting 8 to 9 miles to the gallon. I spoke with another guy that said he’s getting 14 to 16 and he’s got a 2020 ram 2500 with the 6.4 hemi and I have the hemi also 6.4

I have the same, but 2019. The algorithm changes with the tire size. I spoke to a long time Ram executive who checked my data & found I’m actually (most likely) getting the 15-16 mpg.

Tire size absolutely changes all the readings for fuel use, mileage, miles driven & speed.

So far nobody has the program to do a tire size reset on our trucks with the hemi.
So I guess we have to live with reality v’ observed data!