Thank you, Where did you find this? or is this personal experience?

 

Well bout 12-12.5 per mile on a tank and this is driving normal lol 225-240 that's half hwy and town and I run my tires a bit more air in the 305/70 I have it at 40 psi now when I first got my truck on a tank I got 187 and it was 8 miles per gal. I've done a lot to it tune up plugs wires cap Hughes Kit it was eating a qt of oil every two days new upstream o2 and needed a water pump so I did the timing set while I was in there but if u driver one of these trucks don't be upset bout how much gas they drink

 

No im not upset about the gas mileage, It has been 3 years since I drove it, ( motor was out for that long ) I just couldn't remember all of it. im not crazy about the 2000 rpm at 60 mph though, I guess as I have been driving my glass van a 2004 chevy 2500 express, I got spoiled with the 400 to 450 miles to a tank of gas. I know I will never see that kind of mileage with the dodge, LOL , one could dream. I have been thinking on taking down the gears to 4:10's that should get me around 1600 to 1800, I know that isn't a lot but 2 to 4 hundred rpms less will make me feel better that the motor isn't riding a high rpm all the time. I am not pulling a trailer with it any more, so the 4:56 gears are not needed.

 

Yeah, but, the expense of changing gears would pay for a lot of gas...... be a long time before you saw a return on that investment....... and 2000 RPM really isn't 'high' for these engines.

 

Yes from personal and a tire size/gear ratio calulator. I have ram a few gear ratios in my truck with a few diff tire sizes.

Thats when they start to suck back gas 2000+rpm, 400rpm over the 3.55.

3.55 gears 245/75R16 = 1757rpm @ 65mph........2546rpm
...............265/75R16 = 1691rpm @ 65mph........2451rpm
...............285/75R16 = 1630rpm @ 65mph........2363rpm
...............315/75R16 = 1574rpm @ 65mph........2242rpm

 

Ok so 1 full tank down 251 miles at 20 gallons comes out to 12.5 miles a gallon. Sounds about rite. So now with this new tank of gas, I will only drive around at 50 mph. 50 mph truck only spools about 1500 to 1600 rpms. So I should get better mileage, and with that I do believe I will be getting new gears and dumb down the rpms. I'm thinking 4:10's with 305/70/16 should do the trick. Plus I got another set of 315/70/16.5 but have to find another set of 10 inch wide wheels for them.

 

That's pretty good mpgs bud.

Here is a gear/tire/rpm/speed calc you can play with.

http://www.grimmjeeper.com/gears.html

Why do you think you have to go to 10" wide wheel for the military 16.5"? You don't have to at all.

 

Thanks for the link, And the reason for the 10 inch wide I need a 4 inch back spacing so they don't rub the frame, and also the tires are actually a 12 wide tire. !0 inch wide wheel will give some side wall bulge, but not like a thinner wheel will. plus they are not military tires these are good year 315/70/16.5, My truck had originally came with 16.5 wheels from the factory, but the wheels are to narrow for the tires.

 

i get about 11 mpg, i usually put in about 23 gallons at the pump and that gets me about 250 miles its not great but i mostly do town driving to work and back, so its not too bad. However i am on ****ty suspension and out of alignment which im getting fixed. If you want better mileage get any sct tuner and tune it to 91 or 93 and drive normally. Make sure you have 180 thermostat if you go that route though.

 

My truck is a 1995, with a ODB1 computer. They don't make a SCT TUNER for my truck, Trust me I have looked into it very far, Unless they somehow came out with one in the last 3 years, I haven't found it.