• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

31's with 3.07's

XbajajeepX

XbajajeepX

NAXJA Forum User
Location
So. Lake Tahoe
Anyone run 31's with 3.07's???? How bad is it? I am running 31x10.5x15 BFG AT's but are worn down to like 30". How much of a difference do you think I will see if I put on new 31's? I am installing some performance upgrades this week, so maybe that will help with the power loss.
 
ya, im running 31's and 3.07's and i've got a header intake and 5.0 injectors it still sucks 5th gear is almost unusable. i'd get gears before new tires or your "performance mods" if i were you. my gears on my garage floor (4.56). i dont think you'll notice much of a difference between bald 31's and new. it sucks but you can definitly pull it off
 
my jeep has 31" BFG ATs with 5spd and 3.07s. its not that bad. 3.55s would be perfect with the 31s and a 5spd, but if you can't afford that right now the 3.07s will easily work. for me im getting ready to step up to 33s so im going to 4.10s.
 
it's not horrible.
in fact, I got some pretty great highway MPG with 31's and 3.07s.
it's going to be sluggish, and your clutch will take a bit of a beating offroad.
 
I am running 31s with 3:07s in a 2.5 MJ. It does ok as long as there is not a hill anywhere to be seen for miles. I find that with the 2.5 it is just easier to keep it in 4th.
 
I ran 31x11.5 with 3.07's for roughly 3 years. As has already been mentioned 5th was virtually gone. For me 65 MPH was the slowest 5th would pull. And even then, the slightest grade and 5th bogged out.
 
I had 31's with 3.07s on my 98' 4.0L with 130K miles and it's not too bad, but not great either. Gas mileage wasn't effected that much maybe lost 1-2 MPG. I put the stock tires back on because I'm going with 33" MTs and 4.88 gears in a few months. I like having the power back with the stock tires, but think the Jeep is undergeared with 3.07s and stock donut tires. 4.88s with the 33's should bring it back to life nicely. :laugh3:
 
I got 33's with 3.07's. It doesnt bother me too much. But you can never go wrong with gears.
 
Heh. Get new gears. Without question. If you've got 3.07s, you've got a 5spd. 4.10s with 31s, 4.56s with anything bigger. Unless you've got ABS, and a Dana35 by extension, where you can go deeper if necessary.

Go back to the top of the forum for the gearing questions.
 
Jonnyjpr said:
I got 33's with 3.07's. It doesnt bother me too much. But you can never go wrong with gears.
Click to expand...

31's and 3.07s is fairly tolerable. 33's and 3.07s is really bogging you down. I had 33's on my 91' 4.0L YJ about 6 years ago.
 
I'm running 31's with 3.07's. Its doable, but I'm itching for new gears to get some of my power back.
 
Your 5-speed XJ with 31" tires will perform well again and like it should, regeared to 4.10s from 3.07s... end of story.
 
Crawler said:
Your 5-speed XJ with 31" tires will perform well again and like it should, regeared to 4.10s from 3.07s... end of story.
Click to expand...

It is amazing the number of XJ'ers have the same setup and have vastly different opinion on it. This thread is a perfect example of it. Everyone is correct. The gearing and tire size siutes their driving style.
 
my 89 4.0(300,000) must be pretty tired cus, my 3.07 and stock 27" tire has a hard time and has know us for 5th, unless your doing 75+ and on the flat!.......31/10.50/15:shocked: I thing she would just lay down and die:sad1: :laugh:

Flash.
 
techno1154 said:
It is amazing the number of XJ'ers have the same setup and have vastly different opinion on it. This thread is a perfect example of it. Everyone is correct. The gearing and tire size siutes their driving style.
Click to expand...
Yup... and like you, I'm about to put 30x9.50s on my 3.55s & AW4 w/2.75" lift... ;^]
 
Flash said:
my 89 4.0(300,000) must be pretty tired cus, my 3.07 and stock 27" tire has a hard time and has know us for 5th, unless your doing 75+ and on the flat!.......31/10.50/15:shocked: I thing she would just lay down and die:sad1: :laugh:

Flash.
Click to expand...
I absolutely hated the 31" 3.07 combination when I tried it 10 years ago on a '93 5-speed XJ Sport, up here in mountain country. I felt like I had to slip the clutch to get rolling at intersections, etc. Regearing to 4.10s definitely brought the "Sport" back into the driving experience, and improved low-range crawling dramatically.
 
Last edited:
I felt that 30's with 3.07 sucked bad... 31's can only be worse. On the highway, 5th gear was about non-existant except on down hills with a tail wind.

I regeared to 4.56's and went up to 32's....life is much better now. Gobs of low end torque to boot with that combo! I can start out in 2nd gear with no trouble.....

Save your pennies... re-gearing really is what it's all cracked up to be...
 
maybe I should have worded it better. I currently have 31's that have maybe half tread left and I am wodering if I will tell THAT much of a difference if I get new 31's. A lot of guys are saying that 5th is useless. 5th works great for me. sometimes I wonder if the previous owner swapped new gears in.....
 
wow ok...i must be REALLY tired cause thats^ what I originaly said....
 
You must log in or register to reply here.

Similar threads

Root Moose
Mild Lifting with OEM Parts
Replies
12
Views
1K
Tim_MN
Tim_MN
K
How does backspacing affect handling? 3.75 vs 4.5 backspacing for 31 x 10's?
Replies
11
Views
4K
XJEEPER
XJEEPER
G
TJ Rubicon NV3550 and NP241OR in an XJ?
Replies
0
Views
2K
GraniteCow
G
K
XJ Overland build plan, need a sanity check.
Replies
16
Views
6K
jeep ride
J
J
Post Engine Replacement Problem Goose Hunt
Replies
17
Views
4K
Jude Cochran
J
Back
Top