I wanted to purchase some 20 factory rims. I was told that the factory installs 3.92 gears in the rear for the 20 inch rims. I don't have the 3.92 gears, I have the 3.55, Do you think it would ride ok or are the 3.55 not tall enough of a gear to push the 20's. Also anyone selling there 20's. I'm in Nj.

 

I don't think the rear end gearing is changed due to tire size, its more of a performance/ fuel economy issue.
My laramie came with the 3,92 on 17" rims.
The 3,55 and the 20's would not change much IMO. nothing noticeable anyways.
You would loose a little towing capacity due to the smaller sidewall on the tire

 

I have 3.55s and 20s, the truck towes just fine i just wish I had limited slip. The fuel mileage is great, i average 18 without an issue.

 

No problem: I just took 17" steelies off my son's ST and put SLT 20' wheels on. Had the dealership recalibrate the speedo & swap the TPSM's. Works great, looks fine, lasts long time!

 

mine has 355's with 20's.....sluggish out of the hole but once you are moving you get torque , more than necessary. I am glad I can't spin my tires...20's cost too much, maybe its cuz it 4x4 they dont spin? Even with everything shut off ESP all that crap

 

You guys have the hemi, I have the 4.7 would that make it even slower from the start. I am not going to race it but I do want it to get out of it's own way. Thanks in advance, Reno

 

The 4.7 is still 310hp and 330 ft.lbs. It will be fine, the tranny will kick down when you need it to.

 

I have the 4.7 w/20's and 3.55 rear end, it carries itself well, it aint no race truck or nothing but it seems to have all the power I need. I really aint never towed anything with it other than a 10ft utility trailer and my Harley but it carried those fine and I sure it could tow a whole lot more.

Check out what thses cats tow with thier 4.7's, (some with 20's) if they can do it with there 3rd generations I sure we can do it with out higher hp 4th generations.......

w w w.d o d g e talk.com/forums/showthread.php?t=217110

youll have to enter that link manually and take out the spaces

 

it all depends on the tire size you put on them. If you put the factory tires on the factory 20's, they are generally 1.5" more in diameter. You will notice a loss in performance since your effective gear ratio dropped almost a whole step to 3.38 from 3.55. Will you be content with it, I don't know. But you will definitely notice it.