Larger tires on a 2500 or 3500

[Dooner]

My build sheet shows that on my 2010 Ram 3500 DRW has 3.73 rearend gears and I have 235/80R17 tires. I was thinking about going with a larger (taller) size tire for more speed with less RPMs. Has anyone done this with their 2500 or 3500 without changing the gear ratio?? What has it done to your fuel mileage?? What size tires did you go with??

I have the 6.7, but would like to hear from the 5.9s too. Only diesels. No gassers.

 

[ramhunter9]

I dont know if I can help as I have 4:10's on 35'S but I get 20's on the highway 18-19 town .

 

[zack]

my stockers are 265/75/17 an i have the 373gears in a 2004.5 2500 an now running 37/12.5/17s around town 12 to 16 highway 18/ 24 some times better

 

[Dooner]

What is your RPMs at 70 mph??

 

[ramhunter9]

Hell , I dunno ..LOL . Never really looked at that one

 

[Stangshcky12]

I'll have to assume you bought a dually for a reason. A problem your going to run into is with the width of tires. Anything over 265 wide will rub against each other in the rear when loaded. This almost leaves you with going to a 19.5,20.5 or 22.5 big rig wheel and after te costs of wheels and tires you pretty much neglect the saving in fuel.
With 35s, a leveling kit and 3:73 my girlfriends getting about 17.5-18.5 mpg average to a tank
I'll have to double check what rpm's at highway speeds, I want to say maybe 1800 at 65 but that's pretty much a wild guess

 

[schroederMP]

Mine are slightly larger than stock (cant remember the bumber) but they messure out to be 31.5" with the load of the truck (and the tires are bald)

I'm getting 14-15 town/city/highway/hauling all of the above...it dont seem to change.

 

[zack]

rpms a little high on this shot lol

 

[ramhunter9]

Put your seat belt on

 

[zack]

lol i was ruuning late

 

[schroederMP]

lol i was ruuning late

you have the 48re in your truck dont you?

 

[zack]

yea why lol..that is my next build after tax time is that

 

[schroederMP]

Its just weird that at 70 I'm runnning 2k on RPMs... at 106 your running 2550 RPMs... looks like I'm gonna have to go that fast and see if its the same. lol

 

[zack]

lol i need to do my trans next losing to much power through it an that way i can up the programmer

 

[Stangshcky12]

This was just playin around in 5th gear, I wanna say 3:55 gears, I'll have to double check
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[Dooner]

What is wierd to me is that the 09 chevy 1/2 ton that I got rid of ran 1750 rpms at 70 mph with 3.42 gears and 6 speed, and my 10 Ram 3500 runs 1750 rpms at 70 mph with 3.73 gears and 6 speed. And if I remember right both had tires with equal diameter, just different rim sizes.
Right now, I am getting 15.5 mpg average city/highway in my Ram. 17.5 on the highway. I was hoping I could get a little better going with taller tires.

 

[ramhunter9]

Might want to check our vendor XDP and see what they have for your truck to gain MPG'S