OffTopic

Real life answer? Even with 5.13's I still need to downshift to maintain speed on hills, much much more than I like. You can turn off the OD, but then my RPMs hover around 4700 and I don't like to keep them that high for any length of time. And yes, I've reflashed for my tire size.

But like others have said, there are other factors that come into play. I have very heavy tires, and I'm usually loaded down with gear when we're going through the mountain passes. It's not as bad when the jeep is empty; I still need to downshift on hills, just not for as long.

abrahamdavalos

so if i went with 33's actually 32.8 tires would i be okay with 3.37 gears that i have now?

HOMEGLASS

I have 35" and went to 5.13. Runs almost like before with 32's and the 4.1.

blkpearl

the formula will get you in the ball park, my wife jeep with 4.10 and stock tires got worse gas mileage becuse it was over geared, (better get up and go) not good fuel economy. 35s, 4.10 put the every thing closer to engines optimal rpm range. got better fuel economy was really surprised, but this with a 6spd,... auto not sure what MPG would be.

if you want performance like factory then use the formula, yea the rubi had a higher cruising rpm, and felt like it had more power all due to gear difference.

Big Clint

So many choices. All I want is slightly better than stock performance and to get rid of the downshifting on the small rolling hills going down a 'normal' freeway. I'm not hearing that 4.10s are quite enough. I have this impression that 4.88 would get me well into the power range, but would be high enough to start reducing fuel economy.

Offroad, I've not experienced anything that 4WL wouldn't climb, and haven't seen any posts that indicate there's problems offroad.

It's just this highway thing killing me.

08 Unlimited

You have two options, 4.27 or 4.56 gears when they come out. I personally will go with the 4.56 set up for my 6 speed. The shop I have used several times before always recommends 4.56 for a good all around gear with 35” tires. This shop does 2-4 vehicles a day and it is the only thing they do. Everything from street rods, to dirt track, to drag racers, to 4x4s, and everything in between.

TEEJ

Well, I can't see how EVERY kind of 4x4 has the same gearing upwind of the diffs, so as to make the tire size the ONLY variable as to what diffs to get.

A jeep might be geared lower than a sand rail for example, mud runners need more tire speed to clear the tread, and too low a gear ratio makes that too difficult, etc.

So - there cannot be one universal tire size/diff ration solution...its an over simplification at best.



We have the specs for the drive train...we do not have to guess.

Its always the same question....we KNOW what FINAL DRIVE RATIO we will have, and what the factory engineers decided was the best for fuel economy (3.21), etc.

What we do from THERE, is to decide how much MORE we want to spend on gas to have better acceleration, climbing ablility, etc.

Obviously, we bought jeeps, so we ALREADY decided MPG was NOT a major issue....so, we LOVE LOWER gears (Higher numerical ratios)....as they make the rig way more torqued.

Torque is good.



An informed decision does require spelling this out though....as observed, larger tires are like an over drive gear set...they deepen your over drive....and, can IMPROVE your MPG if within reason, say up to 35's....larger than that, so many OTHER factors come into play, that at that point, you'd just go as low as you could and hang on.

So - if you do not CARE that gas will be $4/gallon, or $84 to filler-up, etc...and would GLADLY PAY that to have more get up and go...well, that's your answer....get the get up and go.

If you are more concerned, get less get up and go, or, keep the go you have, etc.

LinkSync

I am on 35s with 4.1 auto in 2dr X.

It is a total PIG going over 65 mph on flat wind free desert freeways.
Going uphill or into a strong headwind it is obviously WORSE.

BUTT! Coming back downhill??? whoooo HOOO!
SO the answer is to only go down hill or wait for the wind to blow your way.
Or maybe drive backwards when going uphill.
That would be ANOTHER reason to have a reciever on your front end...

Having flashed the rig for as big as they can in stock computer my speedo is still incorrect.
GPS confirms that when going 75mph the speedo shows exactly 70mph.

PERFECT!
If I obey the speedlaws by speedometer I am only just a tiny bit TOO fast and avoid a ticket and still going too fast.

When in 4WL it doesnt matter what gears/motor/power blah blah blah you have.
You'll do just fine.

It's the street issues that are a drag for those of us that notice that sucking sound in our wallets.

The thing to think about is simply this: How much gas would the price of re-gearing buy? vs. How much fun feeling are you not experiencing in your new PIG?

Most folks I know that spend $35k+ for their modded JK will never go any where that would use all of a STOCK JKs crawling ability. For them it's all show and no GO and SO they should spend as much as they can/want to on whatever they want when they want and the hell with whatever the naysayers say.

For those that risk it all on doing carzy shit that makes their tummys twirl and their buttholes pucker, and yanks a laugh out from way down deep where the fear lives... who the hell cares about all the lamer angst? It is indeed all about the fun. And then you die.

So your value system meets your fun factor, and the spin stops here, where the rubber meets the road or the dirt or the rocks, or the mud or the snow, or the water or your daughter.

What is it FOR?
The answer to that is the answer to all other questions.
Then comes the priority listing as you tussle with the puzzle of things like money and time and environment and selfishness and love and everything else in your life/lives.

It's all in there and could hurt your head or your heart if you get it wrong or even if your get it right if your like me and care about both sides of things.

Just don't be afraid to care and everything will be o.k.
Everything is a negotiation of some kind in life anyway.

I would like to re-gear my PIG so it would be a faster more ballsy PIG.
Maybe one day I will.
But I need more bullets and gas and a better skid plate for my gas tank and oil pan...
And oh yeh I almost forgot, My dogs gona whelp me 10 pups here pretty soon and I need a whelping box and have lots to learn about all THAT...

So technical info matters!
Personal info matters MORE!
New JK owners can get WAY TOO EXCITED and end up spending money they shouldn't for things they really don't need RIGHT NOW.


For me I found that writing things down (actually typing them into a spread sheet) really helps.


I found I really did NEED:

Absolute basic equipment regardless of mods:
Walk out daypack complete with good first aid and basic survival things for 3 days that is light but complete and includes WATER.
Basic but complete tire care equipment and fairly advanced tools for re-pair and recovery including air comperssor.
A topo map compatible hand held GPS unit with extra batteries in daypack.
A gun.

And now the "Mods":
1) 3" lift and go to 35's
2) gerry can holders that still keep my rear view a working rear view.
3) needed the d-shakles (or some other good h-lift points to change tires with it and lift etc.) add to all 4 corners.
4) good Nerf bars for now untill sliders are a lot cheaper ( now I know I may never get sliders).
5) after crushing my muffler I needed a new one and skid plate for it.
6) #5 above taught me I and also needed a skid for the evap housing and more later on.
7) so a small flow thru gibson muffler needs a CAI (until I get a good snorkel ( way off still, but coming) so I "needed the CAI.
BTW with both CAI and flow thru muffler, imho I have lost low end power in 2WD
8) experience solved my winching questions, and prooved to me that a portable winch was the way to go for me. One that would go either front or back at need. So a 2" reciever in the front bumper was needed as well as the winch rig.
9) Having all the above got me caught out (way out) at night which taught me I needed good trail lights.
10) Everything above increased the need for a purpose built camping trailer that is off road capable and in particular is desert ready.
11) Having all that has taught me that my rifle isn't good enough, I needed a pistol that I could better ignore yet still have with me as I hike and camp etc.

And the list goes on....

Just sharing my/your experience here for whatever comfort , humor it may bring.
We are not alone in our persuit of happiness!

This forum ROCKS and its like Eddie's nic says, it's a Way Of Life.

Enjoy

Ewok

How much do gears cost to getput in? I heard around 1500 including the purchase of everything!

flippersjeep

I have 35's, manny and 4:88's, best mod I have done, dont even use 1st gear and run approx 3400 rpm at 85 mph, have lots of get and go between 65-80, when you step on the gas, the Jeep moves quite well