Gas Mileage and performance with stock gearing and 33s

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Junior Member
Mar 5, 2023
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Durango, Colorado
Ram Year
5.7 hemi
Hey all, first post to this forum, and I'm sure I'm asking a question that's been beaten to death already, but couldn't find anything in the thread search. I have a 2012 2500 4x4 double cab with the 5.7 Hemi, stock gearing, stock ride height, and slightly above stock tire size (31s). I'm currently getting around 11 city and 16-18 highway, depending on speed. I'm going to be getting new tires for it this summer and have been looking at going up to 33s because I use my truck on a lot of forest service and non-maintained roads for hunting, camping, and just outdoor stuff in general. I will likely also be doing a leveling kit and new shocks, but that probably won't affect much compared to larger tires I was wondering if any of y'all have any insight on how this may affect my gas mileage and general performance and if there are any tips to help improve both. I've read that sometimes on higher mileage Hemis, replacing the spark plugs with newer high-end plugs can gain a couple of MPGs, so that is something I would look into if that would actually work.
Again, I realize this has probably already been discussed but couldn't find it in the searched threads, so if anyone has a link to threads that have discussed this, I would greatly appreciate it.


Senior Member
Sep 12, 2014
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Ram Year
2022 Ram 1500 5th Gen, Big Horn, 4X4, Crew Cab, 6'4" Box
hemi 5.7L, 345 cu in
Figure 2 mpg doing all of it.
Rolling resistance of tires is most o fit but lift will change airflow and cause reduction of mpg too.

Of course, better plugs will function better.
How much HP, not enough to justify the cost of the plugs but the engine will thank you by living longer, and performing better.

Bototm line, you bougth a V-8, any change, from OEM is going to reduce mpg.
Throwing sticker on the darn thing is slight wweeight addition and will change MPG,
might have to figure it out the qo out, 100/ thousandth fractions, to get the number, but it will have an affect.