I just dug this up:

According to that, my new gear ratio, saying if I was going from 265's to 285's, 3.68. Makes it seem like 4.10's are a lot more than what is necessary to be back at stock performance.

 

I don't write much and have been gone for 7 months, but take out the AC bringing down resale? You guys would actually sell your Truck? Damn I must be in the wrong place.I ordered my Ram backin 1997 plan to keep it around as long as she will have me. As for MPG well I am lucky and don't have to drive much only have 136k and figure as a TRUE tree hugger it is myDUTY to keep this vehicle out of a land fill and or trashing the environment to get materials for a new vehicle or energy to recycle it. OK at the miles I drive now and the amount of time I spend out of the country having a paid off vehicle is the way to go but I am still waiting for that magic part that will somehow get me 25 mpgs when you guys get it let me know

 

I just dug this up:


[blockquote]quote:

ORIGINAL: The Burning Rom

These are the formulas I used to figure out my response, with a little added for rotational mass compensation. They're direct from Reider Racing...the only company I'd trust for rears and gears.
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Calculating Tire Size

Tire Diameter = (2 x Section Width x Aspect Ratio) / 2540 + wheel diameter

Ex: 245/75/16 tire

Diameter = (2 x 245 x 75) / 2540 + 16 = 30.46850394 -> Rounded to 30.5
---------------------------------------------------------------------------------------
Calculating Gear Upgrade When Changing Tire Size

New Gear Ratio = New Tire Diameter / Old Tire Diameter x Old Gear Ratio = New Gear Ratio

Ex: 32.9 (that's what 305s are) / 30.5 x 3.55 (assumed stock ratio) = 3.829344262 -> Round to 3.82 or 3.83
---------------------------------------------------------------------------------------

[/blockquote]


According to that, my new gear ratio, saying if I was going from 265's to 285's, 3.68. Makes it seem like 4.10's are a lot more than what is necessary to be back at stock performance.



well if these numbers are correct then we might have a bit of an ishue!

 

can someone tell me real qwik how to highlight a post and get it in a box for my post.i tryed above but i dont know how.

 

Since I have had made some big changes to my trucks, I think I can pipe in here a little bit. Recently, I had the lift taken off of my truck, and the 35" tires as well. As of now, I am running 285/70/17 tires with 4.10 gearing. I am getting 13.5 city, and 19 highway. I couldn't be more pleased. I know the numbers aren't exactly hybrid numbers, but they are very respectable for a truck with a 360ci in it that is still relatively big for a half ton truck. Honestly, I didn't feel a ton more of horsepower back, but the mpg increase showed. When going 50mph and above, the truck floats effortlessly now, and this is where the truck really accells now. The 35s never allowed my truck to float, it was constantly working to maintain speeds. The 285 is still a big tire, but it does allow breaks for the truck to coast which helps. When I ran 35s, I was getting about 225 miles to a 26 tank of a fuel. With the 285s, I got 345 miles to a tank of a fuel. That extra 120 miles makes a giant differance for me in a week. It allows me to get my next paycheck before I have to fill up, and I love it. So if your looking for better gas mileage quickly, I would put 265s on your truck if you have 3.55 gearing. Plus it will probably still look good if it's a regular ram because it won't be as high as mine with the offroad package. I couldn't be more happy with my decision to lower the truck down. Sure it was tough at first, but I love my truck even more now. I can go down the highway at 80mph easily and safely,the truck has way more towing power, and it's just much more fun to drive.

 

Thanks for that, hopefully I'll be swapping tires with my buddy soon (he has 265's). Supposed to do it this weekend but it calls for rain so we'll see. I know exactly what you mean when you say the truck is constantly working to maintain speeds on the highway. If I come to any hill I have to fight if I want to keep the same speed.

 

Even now with 285s and 4.10 gearing, the truck takes a lot of work to get up to speeds. The only differance now is I can actually maintain speeds. But I just think it's the nature of these motors. They are giant motors for half ton trucks, they are old school, and are meant for heavy hauling. My truck at full throttle is obnoxiously powerful and quick, but daily driving is a toll for sure. It's why I made the decision to take the lift off and size the tires down. I knew if I wanted to keep my truck, I'd need to make sure the truck was light on it's feet, and for **** wouldn't prematurely be breaking. I actually like the look of my truck better now, it looks like what a half ton is supposed to. My truck looked like a 2500 before, but it actually performed worse than a half ton because it was impaired. Now my truck hauls *** when I'm into to it, and drives as normal as possible. The only thing excessive about my truck now is the exhaust. I'm even thinking about toning it down a little bit. My exhaust never quites, it is constantly humming away. I love it, but on long trips, the drone can be taxing and make driving become unjoyable. I love my truck so much, it's a very cool truck. I love knowing I have a giant 360 in my half ton truck, but it takes some compromises because of its poor gas mileage habits. But a half ton with a 360, 13.5 city, and 19 city is an excellent compromise to me. Besides, a 285 is not a small tire at all, I love my truck 5x more with the offroad height and 285s. I think a 265 will be the best you can do with 3.55 gearing. It will still look great, and your truck will float better when you get up to speeds.

 

Pretty impressive 13.5 city and 19 highway. How many times have you calculated it to be 19 highway? Seems really high for the 5.9. Might end up doing the tire swap this sunday, I'm anxious to get it done.

 

I've filled the truck up from full to almost completely empty two times now. I also have the overhead so I use that as well. It's actually very accurate, it is very similar to my manual calculations. I think now since I've sized the tires down, all the work I've done with the longtube headers and 3" exhaust and K&N intake are finally helping out.

 

I haven't kept record of my mpg yet,as ive only had the truck for a couple of weeks now,but plan on it.

I can say I am very impressed with the mpg though as I have filled it up on Mon In Jersey and came back to PA and have been driving it every day back and forth to work and am still over half a tank.

I was driving a 97 Aerostar before and was getting 1.5-2 wks out of a full tank doing the same driving.

I was really only hoping to get a week out of the truck and am pleased with where im at now.I am a coaster though.I rarely get above 55 so that helps.