Is anyone running 31s with 3.07 gearing?

[SnowyXJ]

Well.. after three years of running a well clapped out 220,000 mile motor in my '89 with puegot tranny, 3.5" lift, 3.07 gears, 235's and towing a trailer usually weighing in around 3500#'s - 6000#'s.. I decided to rebuild the motor, swap the axles with ones out of a 90 limited (non vaccum) with 3.55's and put a new clutch in and what a difference..

I went from never seeing fifth gear while towing the trailer, to using it almost every time I was on the highway.. Granted.. I drive a lot faster than most people do, but.. I was shifting into Fifth around 60 and it would still gain speed.. I think I had to downshift once when I was towing another Jeep on the trailer.. and that was a long hard grade too.. but.. other than that.. I'm happy with my 235's and 3.55's..

Sadly.. I just recently ripped off one of the rear spring frame mounts so.. I think I might get rid of her.. She's done us good..

 

[Twisted XJ]

I run 35 mtr's with a stock 8.25 and stock 30 with yes 3.07 and it sucks, but I have also wheeled everything in UNF. 4lo is fine but stopping on a dime is outta the question maybe a UFO but not a dime. Yes upgrades are in the plans, but so is a Viper, a Hayabusa,a mansion blah blah blah. You get the idea.

If you want to wheel and that is all you have you make it work or else just look at through your front window in the driveway.

 

[Kejtar]

I run 35 mtr's with a stock 8.25 and stock 30 with yes 3.07 and it sucks, but I have also wheeled everything in UNF. 4lo is fine but stopping on a dime is outta the question maybe a UFO but not a dime. Yes upgrades are in the plans, but so is a Viper, a Hayabusa,a mansion blah blah blah. You get the idea.

If you want to wheel and that is all you have you make it work or else just look at through your front window in the driveway.

I don't think the idea is not to wheel, but not to jump ahead of yourself in upgrades. If you're planning bigger tires, make provisions for everything that goes along with it: brakes, gears, upgraded steerings, upgraded axle shafts (based on needs).
I am at a point where I kind of want to go to 35's sooner or later and lift wise I was almost able to stuff them in last time I changed my tires, but I knew that my steering components wouldn't be able to survive nor that my brakes would be able to handle the 35's so I stuck with 33's.

 

[mwm]

how would 32's with 3.73's work? Im one of the lucky 87 tow package with a 44 and 3.73s...

It would be fine. I just put 4.10s in mine with 31's its way diffrent but almost to slow...Im so used to my 3.07s. I think 3.73s would be a nice all around gear ratio to go with.

 

[Menzenski]

Thought I'd bring this thread back from the dead to give an update. I got my 31s on about a month ago, and the 3.07s suck major ass. Since I put the 31s on, I have not used 5th gear once. My gas mileage has dropped from about 17 mpg around town down to about 13.75 mpg. I have to wait forever for a long gap in traffic before pulling out, because it takes me so long to get up to speed. When I drive home from downtown (up a several-mile-long hill), I have to drive in the slow lane with my flashers on, in third gear. I can't wait until April, when my brother and I can start combing the junkyards for some 3.73 or hopefully 4.10 axles. I have almost no clutch left as it is, so I really don't want to wheel it without lower gearing.

I don't know how some of you with 31s (or even 33s or 35s!) and 3.07s can think that they're okay.

 

[87manche]

I don't know what the difference with my truck is though, but I don't have a problem with my 3.07's and 31's. I can drop into 5th at 55 and hold a hill in 5th without lugging the engine at that speed.
Going to WF I averaged 23.5 MPG, and that was with 200Lbs of tools and spare parts in the back, and a half a bed of wood.
I did green and white without abusing the clutch badly, but I did spend most of the day in 4LO.
It's not so bad, just don't think you're going to win any 1/4 mile races.

 

[Kejtar]

Thought I'd bring this thread back from the dead to give an update. I got my 31s on about a month ago, and the 3.07s suck major ass. Since I put the 31s on, I have not used 5th gear once. My gas mileage has dropped from about 17 mpg around town down to about 13.75 mpg. I have to wait forever for a long gap in traffic before pulling out, because it takes me so long to get up to speed. When I drive home from downtown (up a several-mile-long hill), I have to drive in the slow lane with my flashers on, in third gear. I can't wait until April, when my brother and I can start combing the junkyards for some 3.73 or hopefully 4.10 axles. I have almost no clutch left as it is, so I really don't want to wheel it without lower gearing.

I don't know how some of you with 31s (or even 33s or 35s!) and 3.07s can think that they're okay.

Thanks for the update! For the 4.11 axles look under 2.8L equipped rigs.

 

[Kejtar]

I don't know what the difference with my truck is though, but I don't have a problem with my 3.07's and 31's. I can drop into 5th at 55 and hold a hill in 5th without lugging the engine at that speed.
Going to WF I averaged 23.5 MPG, and that was with 200Lbs of tools and spare parts in the back, and a half a bed of wood.
I did green and white without abusing the clutch badly, but I did spend most of the day in 4LO.
It's not so bad, just don't think you're going to win any 1/4 mile races.

You got a magic truck?

 

[Menzenski]

You got a magic truck?

Yeah, you must have one. I have an XJ, not an MJ, but mine probably weighs even less than your longbed. I have a two-door with no back seat, no plastic interior panels, no rear seatbelts, no rear flares, and no rear bumper. I have no roof rack and no roof-mounted lights, and you get what? 8-10 miles per gallon more than I do? I have a 4.0 too; I just don't get it.

87manche, what's your secret?

 

[87CherokeeChief]

it is really that bad for you?? i can get up to speed quite quickly(given its a jeep with 31s) in town mileage is crappy but i dont exactly drive in a conservative manner. passing on the freeway is pretty easy, i dont really use 5th gear unless its flat or downhill but 4th is fine and i dont usually need to go into 3rd inless its a real hill. I went on a 300 mile trip and got over 23mpg there and back...lots of crap in the back of the jeep too.

 

[Menzenski]

it is really that bad for you??

It is. It's probably not helped by the fact that my entire Jeep seems to be falling apart. It's only got 170,000 miles, but I have the feeling that it was abused pretty hard before I got it.

There's a D30/D35 combo out of an 89 YJ for sale near me, cheap, with 4.88s. Hmmm...
Probably not a good idea, but fun to think about.