Need Advice 3.21 ratio

[Beraiurak]

I have a 2014 ram 1500 with 8 speed and 3.21 gear ratio, I'm looking at doing a 6" rough country lift and 37" kanati mud hogs, I've seen mixed advice on rinning large tires with the 3.21 and some people say it lacks power stock currently I have 265 kanati mud hogs and have no issue breaking them loose on pavement, and from what I've seen the Rocky ridge rams for the most part are running 37" tires with the 3.21 ratio. So should I go with 37's or be on the safe side and go with 35s and get the 37's when I can do a regear down the road?

 

[Csanders1992]

Plenty run 37s with the 3.21s. You'll just have to get used to the fact that your fuel economy will suck and your truck will be a dog. 35s would be better


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[69GWC]

You should swap them up with 3:92s, your truck is going to suffer with those big tires and high gears.
Power,fuel mileage and even your transmission will not like it all though you might not see anything other than the fact it searches for gears alot but it will be hard on your overdrive gears.

I guess thats if you can buy a new front carrier and ring and pinion and install in it.

 

[AustinB]

Anyone with actual experience with 8spd 3:21 that went from 35s to 37s... Or vise versa that can testify to the difference?


IMO

 

[Hitman0002]

So, last I was tracking you will be able to re-gear your rear end but the front you are SOL the front has something welded in it, can't remember what was welded. That being said that was 8 months ago that I went through my build and last I checked still no re-gear availble.

I went through the same stuff when I was trying to figure out how 37s would be with the 3.21 gears. No one really had an answer. I went with 35s . I regret going with 35s. The truck still has plenty of power and wish I would have went with 37s. Plus my truck with the 35s looks like it needs more tire. My opinion though. Go 37s and program it. You will be good. MHO

 

[sbuko213]

I'm leveled 35's w/ the 3.21's and I still walked on some texas boy in his chevy. I've got a tune and I'd highly recommend getting one.

 

[AustinB]

8spd?


IMO

 

[Hitman0002]

If you're asking if I have an 8sp. Yes, I do.

 

[sbuko213]

8spd?


IMO

Yep

 

[Beraiurak]

I plan on getting a performance tuner as well, and my fuel economy isn't a big concern my last truck got about 8mpg

 

[ekholmgren]

I'm leveled 35's w/ the 3.21's and I still walked on some texas boy in his chevy. I've got a tune and I'd highly recommend getting one.

What tune are you running?

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[Hitman0002]

Sorry to bring up an old thread

Sorry to bring up an old thread. I just want anyone to that still has questions about this topic that I am installing 37's tomorrow. For those wondering they are Pro Comp AT Sports (37x1250x20). My current Toyo ATII (35x1250x20), I don't like at all. I have almost 40k on them in just a little over a year. They just wore completely odd. All the inner tread on the tire is worn down to almost bare while the outside if I could I would get another 10k out of. Had the truck realigned multiple times with tow and camber, everything possible, looked at to include air pressure. Was not a fan of the Toyos.

I will post back on here about my opinion of how everything feels.

I am still running my Diablo Trinity tune.

 

[misuracaf10]

If he's gonna run 37s and is gonna re gear.. Might as well go to 4.10?


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[Hitman0002]

SOOOOO I have about 30 miles my 37's w/ 3.21 gears. I retuned the truck right after I got the tires on. obviously there is a lose of power but it still has it. The 37's i put on are actually some how 5lbs lighter per a tire. Don't ask how I am just going by the manufacture weight. Feels good and I like them so far. The real test will be next friday when I have a 500 mile drive then the following week back home. Will update.

 

[misuracaf10]

SOOOOO I have about 30 miles my 37's w/ 3.21 gears. I retuned the truck right after I got the tires on. obviously there is a lose of power but it still has it. The 37's i put on are actually some how 5lbs lighter per a tire. Don't ask how I am just going by the manufacture weight. Feels good and I like them so far. The real test will be next friday when I have a 500 mile drive then the following week back home. Will update.

For whatever reason those ATII's are heavy, even the 33s are 74 lbs ... I'm curious as to why myself


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[Hitman0002]

I have no clue but those pro comp AT sports are actually cheaper than those toyos and have a far better warranty. How a 37 is cheaper, lighter and better warranty.

 

[Hitman0002]

Running 3.21 with 37's

So I now have about 4k on these tires in less then a month. I might drive to much. My first 1k trip with these I wasn't happy about my MPG. I got it's a truck with 3.21 gears and 37's. I am just letting other know that are interested in this tire/gear setup. Yesterday, I drove 300 miles back home and actually got 19.3 MPG. The terrain was pretty flat most of the way home with some hills a long the way. Anyways Love the tires I do wish I had a different gear setup.

 

[NoveskeFan]

Thanks for the updates. I have 3.21's and am just wanting to do a 4" lift with 33 or 35" tires. Just trying to figure out if I can use my stock 20x9" wheels.