Hey guys I'm new to the forum and looking to purchase my first diesel. I have researched many mixed reviews of the 3.31 vs. 3.55 and am still undecided.

The truck I'm looking at has 3.31 and the dealer has a set of 20'' factory wheels that he is willing to throw in. I know that to get the 20'' from the factory you have to have 3.55's but does any one have any experience with 3.31's with 20'' wheels and a large (33''-35'') all terrain tire.

Any feedback would be GREATLY APPRECIATED! THANKS

 

I've got 20's on my 2011 F350 with 3.31 gears. It works great. The only thing that I'm still working on is reprograming my speedo with my service manager. Right now I have it programed for the 3.31 gears & the 20, but it threw the check engine light on. So we're gonna try & play with it some more. I dont really want to buy a programer just for tires if I dont have to.

 

if you plan on upping tire size to a 35", get atleast a 3.55 if not 3.73's (if available)

if you tow large loads, get 3.55's.

3.31's will be fine, but 3.55's will do better.

edit: if you do more city driving than highway driving you want a higher number for your gear ratio. if you do more highway you want a lower number. either way with 35's i'd stick with 3.55's at a minimum.