Last night I was messing around with formulas to find rpms with different tires and gears and when I calculated rpms at 60 with the tires and gears the door sticker says I have- 3.21x.69x60x336/29.3=1524. Weird, at sixty Im runnin about 1700ish so I switched it around and tried 29.3x1700/(60x336)=2.47 and 2.47/.69=3.58 which means I must have 3.55 gears. So I apologize for any misstatements Ive made while under the impression I had 3.21s

 

I didn't know any Rams came with 3.21s. I thought 3.55 was stock except in the Off-Road models.

 

When I ordered mine new, there was four axle ratio options for 2WD, and two for 4WD (from memory).

 

The ratios available in the 9 1/4 axle were 3.21, 3.55, 3.92 and later 4.10.

Grant the Old School Dodge cars and vans that used that axle had even taller ratios available...but still.

You may have a door on your truck from another truck....?

 

Its not on the actual door, but i guess the door jamb. Its nice though, cause now I have no need to fear getting 33s

 

So you think 33's with 3:55's is a good thing?

 

I'd go to 4.10s for anything larger than stock.

 

Here's a good link to try, it calculates your old tire size, new tire size, current gear ratio. It will give you suggested, high and low gears and effective ratios. Remember just because you running 4.10s for example with 33" tires, your effective ratio is not 4.10. More like back to factory 3.55.

http://www.4lo.com/calc/geartire.php

 

According to that site my effective gear ratio is 3.28:1 (3.55 stock)

 

Mine says 3.42.
WTF?
My tires are bigger than your's.