Well I just came over from the darkside(chevy) and bought a 2012 Ram 2500 Laramie mega cab 4X4. My question is I have the 5.7l with 3:73 gears and will be pulling a 5th wheel camper and a boat behind that, with a total of about 11,000 lbs and I am looking to put 20" wheels on it. Will this reall screw with my towing ability of the truck? Thanks for the help....Mark

 

If you buy a quality wheel and tire package it will not affect your tow rating.

You will however see worse gas mileage and poorer acceleration and a slightly rougher ride.

 

It will most defiantly effect your towing. By installing larger diameter wheels you are changing the effective gear ratio to the ground.

Installing larger wheels will make your gear ratio taller and will throw off your speedometer. You will be traveling faster then the speedo says and putting on more miles then the odometer reads.

Now, none of these things are a big deal normally but pulling the 5er and boat at the same time, I would not recommend upping the tire/wheel size. I did the exact same thing on a diesel I have a few years beck and although I had plenty of power (diesel) it most certainly effected the MPG and hole shot.

I believe I found a gear ratio calculator once that you can input your current gear ratio - tire size and then the new tire size and it will do the calculations as to what your final drive gear ratio will be. May be able to google it and see if you can find it.



By the way, Congrats on the new truck!!!!

 

I forgot to add,

On the Ford trucks I had in the past you could take it to the dealer and they had software to change the wheel/tire size so the speedo and odometer would read correctly. I would guess that Dodge would have the same ability?

 

What Jason said only applies if you change you OD. If you go to a lower aspect ratio tire with your larger rim and thereby maintain OD you do not affect effective gearing or speedo.

 

CORECT-O-MUNDOE

That did not even enter my mind. Thank you!

 

what alot of people on here are forgetting is that dodge offers ram with a 20" stock option. as long as you dont throw oversize tires on you will be fine. is it easier for your truck to turn 17" wheels and tires? yes.

you'll be alright

 

If you make the swap make sure you are getting 20" tires that are LT (light truck) not P (passenger). That is the biggest factor in being able to pull that load.