4.88s with 40s and 4:1 tcase

wayoflife

Administrator
Staff member
Did you swap in a Dana 44 in the front or are you still running the Dana 30?

Good call! Didn't even bother to ask what was up front. Bad enough to try and run 40's on a 44 but a really bad idea to run them on a 30. If it is a 30, 4.88 is the highest ratio I would go regardless of tire size.
 

Braxtonsag

Member
Did you swap in a Dana 44 in the front or are you still running the Dana 30?

Good call! Didn't even bother to ask what was up front. Bad enough to try and run 40's on a 44 but a really bad idea to run them on a 30. If it is a 30, 4.88 is the highest ratio I would go regardless of tire size.

Like nbunga said I have a pr44 up front or I wouldn’t even be considering it lol. From everyone’s feedback I’m thinking I might as well go ahead and see how they do. If it ends up sluggish I’ll just go to 5.13 and that should give me roughly the same gearing I’m at now which I absolutely love
 

wjtstudios

Hooked
Like nbunga said I have a pr44 up front or I wouldn’t even be considering it lol. From everyone’s feedback I’m thinking I might as well go ahead and see how they do. If it ends up sluggish I’ll just go to 5.13 and that should give me roughly the same gearing I’m at now which I absolutely love

Are you running a ram on it? I can’t imagine trying to turn 40s in and kind of sand or rocks with out one.

One more thing to keep in mind are your front unit bearings. They’re not designed for tires that big and will wear out fast. I’d swap them yearly or more depending on how much to take it off pavement.


2015 JKUR AEV JK350
1985 CJ8 Scrambler
 

KevinG

Caught the Bug
I got a little scared and thought that I was having deja vu.

https://wayalife.com/showthread.php/58476-35-Spline-D44-Vs-SF60


Lot of sound advice in your thread from a few months back, but sounds like you are looking for someone to say "get 40s"

I’ve played with the idea of running a 40. The 38s have done well and I haven’t had a single issue, but just thinking 40s would probably be too much for oem 30 spline. Before anyone asks why, my wife hates getting her ass beat offroad, so the easier the jeep can walk up and over things as small as a fist sized rock the better. I think with my habits of a soft foot and not forcing the jeep to do something it doesn’t want to do I could get away with the 44 R&P, but that’s another reason I asked about the sf60, in case I need to eliminate that from the equation.

I'm stashing away money to make the jump to 40's. Get 40s and report back how great they are so I can stop saving up and just buy them all ready.
 
Last edited:

KevinG

Caught the Bug
I know he posted that chart that I’ve seen prompt some arguments, just asking tho, anyone have any opinions on this calculator?
https://www.rocky-road.com/calculator.html
I’m not familiar with the company or the calculator. I’m not trying to hijack the thread either. Just asking what you think of the numbers.


Sent from my iPhone using WAYALIFE mobile app

I'm a big fan of that calculator! Now just to find out who makes a 46 inch tire :hmm:
 

Braxtonsag

Member
I got a little scared and thought that I was having deja vu.

https://wayalife.com/showthread.php/58476-35-Spline-D44-Vs-SF60


Lot of sound advice in your thread from a few months back, but sounds like you are looking for someone to say "get 40s"

That thread was more so a feeler on whether an sf60 was worthwhile or not, ended up deciding against it since everyone said they were a waste of money. I have spare new r&p laying around for my current setup so if I do manage to break it I’ll be able to fix it and potentially revert back to 38s.

I just don’t really have the desire to go full float. I’d absolutely love it but the cost to do it correctly wouldn’t get its use the 2-3 weeks I get to spend out west exploring every year. The 40s are really more of a ground clearance thing for me. Don’t need em by any means and just wanting to change things up as I get bored with setups every 6 months or so
 

KevinG

Caught the Bug
That thread was more so a feeler on whether an sf60 was worthwhile or not, ended up deciding against it since everyone said they were a waste of money. I have spare new r&p laying around for my current setup so if I do manage to break it I’ll be able to fix it and potentially revert back to 38s.

I just don’t really have the desire to go full float. I’d absolutely love it but the cost to do it correctly wouldn’t get its use the 2-3 weeks I get to spend out west exploring every year. The 40s are really more of a ground clearance thing for me. Don’t need em by any means and just wanting to change things up as I get bored with setups every 6 months or so

Ha ha. I meant no disrespect at all. I actually have a huge desire to go full float. Bent flanges suck.
 

jorgelrod

Hooked
I'm on a similar boat, I'm on 4.56 and 35's. Leaving in Florida, I'm sure when I go to 37's I won't feel underpowered, my fear is when I start crawling....


Sent from my iPhone using WAYALIFE
 

OverlanderJK

Resident Smartass
So you don’t wheel hard why are you worried about your transfer case ratio? By the sounds of it you would not even really use 4wd much. What’s the big hold up? If you need a lower transfer case ratio you need bigger axles.


Sent from my iPhone using WAYALIFE
 
Top Bottom