4.56 vs 4.10 (d30/8.25) 97XJ

[What Rd]

Here's another option: leave the front open for now. You'll be amazed at how much better your rig wheels with just the rear locked. Plus, you can take the 300 to 400 bones you would have spent on the front locker and put it toward a selectable rear. Having the front open in the snow will allow one front wheel to maintain ground speed for more effective steering. A front locker means both tires are pulling, but they alternate between steering and sliding a bit unpredictably. Just another possibility.

 

[Ramsey]

front lock right is 250 or so, but good point about hte snow driving. not a concern down here though

 

[Double Down]

Okay, now I just got confused. I know everyone has their opinions, but someone just said if I they had to lock one, they would do the front and then you said another option is to leave the front open.

So humor me, what does it mean to leave the front open, I kinda know, but I'd rather hear from people who definitely know.

And by selectable rear, you mean ARB? Which if that is true would mean I would have to put in some sort of air system to run it?

So you say in the snow, the front locked is unpredictable but because both tires are pulling and steering at the same time, but with it open you are saying that it is easier to manage in the snow? But what about the mud and rocks when I do get a chance to go offroad?

Thanks,

Chris

 

[woody]

Hey...no problem guys. Your right about the load between the 80/20, we don't know. Woody says the range between 4.10 and 4.56 is acceptable for 31's. Which is consistent from what I have read from the forums. So different opinions regarding gearing from one side of the 'acceptable' range to the other doesn't seem to make anyone a moron in my book.

matt

:kissyou: You're the one who called out morons... Dammit if you haven't caught one. I'll rustle up a miscreant if we need one...

Consistent with what I've found... everyone's experiences are different (and valuable, if they can relay them objectively.) but there are some generalities.

One is that (within reason) overgearing works better than undergearing.

Two is that many folks overestimate or generalize (assume) their tire size when ciphering. Measure from the rear hub center down to the driving surface, multiply by two and ad the wheel dia. to get a working size. Most 30"-35" aren't

 

[Ramsey]

for best offroad performance lock the front over rear, in my opinion of course. many people run them up front that also run in the snow and they havent died yet. lock right front first then no slip back later or at the same time if affordable. do some reading on driving locked up front in the snow(search) and then make your decision

 

[Purple]

i have a 98 with same setup as yours, been watching "diff&pinnion stories" for a while now... i think i will go with no slip for the rear and lockright for the front...

 

[ILLXJ]

i think i will go with no slip for the rear and lockright for the front...

This is the set up I am running. In fact it is What Rd's old 8.25. I had 4.56's installed in Jan. & I am running 31" Trxus. It is great. I wish I could go to 4.88's because I know I will miss the power when I go to 33's.
As to driving with auto lockers in the snow it just takes some getting used to. This past winter I didn't even use 4 wheel drive on road. With that said I will not let my wife or kids drive it in bad weather. HTH. JIM.

 

[NHextremeXJ]

Okay, now I just got confused. I know everyone has their opinions, but someone just said if I they had to lock one, they would do the front and then you said another option is to leave the front open.

So humor me, what does it mean to leave the front open, I kinda know, but I'd rather hear from people who definitely know.

And by selectable rear, you mean ARB? Which if that is true would mean I would have to put in some sort of air system to run it?

So you say in the snow, the front locked is unpredictable but because both tires are pulling and steering at the same time, but with it open you are saying that it is easier to manage in the snow? But what about the mud and rocks when I do get a chance to go offroad?

Thanks,

Chris

My turn.........my opinion.....4.56's and ARB in the rear. Reason: 20% offroad you will have good power to turn up to the 33's you may use. the ARB will give you great selectable traction when you need it and not when you don't(snow on the interstate). Plus you will have unlimited air for your tires. 80% on highway: you will gain the lost power from the larger tires. Overdrive will actually be usefull. You won't soil yourself from an automatic locker engaging unexpectadly in the snow. assgas:
P.S. Most people lock the rear first because more weight is transfered to the rear when climbing hills and such.

 

[ArcticXJ]

You won't soil yourself from an automatic locker engaging unexpectadly in the snow. assgas:

Unexpectedly? If, after driving for all of 15 minutes on it, you dont know or cant *predict* when or under what conditions your automatic locker will or will not engage, then you honestly werent to the point where you needed one in the first place. Ive spent these last three frozen winters in Alaska with a Detroit and bias 35s and not once did I "lose it" by way of an "unexpected" locker engagement. Locker or no locker, dont jump on the gas on snow. Thats common sense.

Detroit and 4.56's. Good to go.

 

[spaulman]

Chris,

I'm running 4.56's, locked front and rear. Last fall, I ran the 4.56's with stock tires for about a week while I was working out some issues. Not once did I think it was too low.

If you want to stop by some time we can swap your 31's on to my rig and you can take it for a ride to see firsthand how you like the combo.

 

[jimbar]

IMO it depends on how much money you have. If you have the bucks then try'em all and keep the options that work best for you. hasta

 

[Double Down]

Scott,

Sounds good to me. I actually just emailed Andy in your TKO group because I am interested in joining up with you guys.

Thanks,

Chris

 

[ExTankerGuy]

I have 4.56s and ARBs front and rear. I have 31s on for now. Pretty good combo. I wouldn't want to do alot of interstate travel though...

 

[virginxj]

get 4.56s, anyone that says otherwise is a moron

First off dont listen to anyone who says do this or you are a moron...

Second 4.10's with 31's will give you slightly taller gearing, ie lower you rpms on the freeway. check one of those gear calculators to match gears to tires, I did it lets you know exactly what you'll get. I have a 30.6" tire (245/75/r16) and with 4.10's I will go 1 mph slower at 2k rpms than stock tire gear. On the road I like these tires and the 3.55 gears, but going down steep rocks where you need to control your speed, you need low gears, and there the lower the better IMO.
Teraflex 4:1 too much bloody $$$$, so gears it is for me(4.10's since I am kind of moronic), I will not go down steep rocks with 3.55's and my larger tires, I just wont feel safe.
As far as lockers, several people who have wheeled jeeps advised against large tires AND lockers on 30/35's, they cant handle the additional stress, I dont know this first hand though so I recomend researching it from other posts and sites.

 

[Ramsey]

and dont listen to a calculator that doesnt take in real world concepts. those are just numbers, it doenst take into account increased rolling mass of larger tires and extra weight from bumpers skids and of course the loss of already crappy aerodynamics of being higher.


4.56s

 

[virginxj]

and dont listen to a calculator that doesnt take in real world concepts. those are just numbers, it doenst take into account increased rolling mass of larger tires and extra weight from bumpers skids and of course the loss of already crappy aerodynamics of being higher.


4.56s

Ok, but aerodynamics are only a factor on the freeway where lower gears hurt your fuel economy, yes they give you more passing power but why not just downshift! With the current gears the jeep drives fine with extra weight. 4.10's by the way are recommended by many people to compensate for the larger tires.
You should really just apologize for the "moron" bit and acknowledge that there is no percfect gear. You seem like you know at least a little bit about this but, so do alot of the people on here. 4.10's are the minimum to bring the rpms back to "normal" anything lower helps offroad and hurts freeway fuel economy. To each his own as they say, I do alot of long freeway runs so I am willing to sacrifice a little off-road.

 

[Ramsey]

spobi. i ran 4.56s w/31s for several months until i got my 33s and it was fine. no suffrage in fuel economy and it was quite fun to drive too. lower gears, what were talking about, dont hurt you on the freeway they put you where you should be. i'm speaking from experience. if you ever regear you will see what i, and many others, are talking about. you did mention 4.10s are the minimum to bring you back. why do the minimum, especially when there is a possiblity of going to bigger tires. regearing can cost a lot. just spend the money once

 

[Double Down]

All "moron" stuff aside, what I want to know is this now:

If 4.10's are recommended to bring back good fuel economy for larger tires, i.e. 31's, then if you go to 33's wouldn't 4.56's do the same that 4.10's do for 31's regarding fuel economy or am I missing something completely different here?

So far what I can tell is that if I stay with the 31's then 4.10 are great for fuel economy and my 20% offroad time BUT if I go with 33's I may want to think about putting in 4.56's instead of the 4.10's?

So basically, if I do go with 33's in the 6 months or so and still ONLY do about 20% offroad and rest driving will the 4.10's be the best for fuel economy, driving, and offroading OR will the 4.56's at that point provide the best fuel economy, driving, and offroading?


Not trying to hasta just trying to understand my options and learn.

Thanks,

Chris

 

[Ramsey]

yes you want at least 4.56s w/33s 4.10s wont cut it. i even wish i had deeper gears(4.88s if the 8.25 would allow it) w/my 33s but the 4.56s are good enough. run down:4.56s and 31s still very much road friendly and great offroad, 4.56s and 33s nearly perfect onroad and still great offroad. if you think you might ever go bigger, do the 4.56s now and save yourself the cost of regearing twice.

 

[NHextremeXJ]

All "moron" stuff aside, what I want to know is this now:

If 4.10's are recommended to bring back good fuel economy for larger tires, i.e. 31's, then if you go to 33's wouldn't 4.56's do the same that 4.10's do for 31's regarding fuel economy or am I missing something completely different here?

So far what I can tell is that if I stay with the 31's then 4.10 are great for fuel economy and my 20% offroad time BUT if I go with 33's I may want to think about putting in 4.56's instead of the 4.10's?

So basically, if I do go with 33's in the 6 months or so and still ONLY do about 20% offroad and rest driving will the 4.10's be the best for fuel economy, driving, and offroading OR will the 4.56's at that point provide the best fuel economy, driving, and offroading?


Not trying to hasta just trying to understand my options and learn.

Thanks,

Chris

Now you are right on track with your thinking. If you have any thoughts AT ALL of going to 33's in the future, then 4.56's.

Ok, but aerodynamics are only a factor on the freeway where lower gears hurt your fuel economy, yes they give you more passing power but why not just downshift!

DUH! frequent downshifting is a cause of bad fuel economy.

Second 4.10's with 31's will give you slightly taller gearing, ie lower you rpms on the freeway.

What? ummm........I think the taller gear will give you higher RPMs.
Double Down, The overdrive will be just fine on highway with 31s and 4.56s. Don't worry about high RPMs.