Strength difference between 4.88 vs 4.56 gears

[renegade_z71]

cut the non sense, if you are worried about stregnth.... get a bigger axle. i seem to have a way to break anything, 10 bolt stock size tires, clutch with a 4cly...
if u are worried about stregnth go bigger.

 

[Goatman]

cut the non sense, if you are worried about stregnth.... get a bigger axle. i seem to have a way to break anything, 10 bolt stock size tires, clutch with a 4cly...
if u are worried about stregnth go bigger.

Sorry, but this comment is more nonsense. (where is this crap coming from?)

It is a totally legitimate question to ask about the strength difference betwwen 4.56 and 4.88 gears in a D30 because there has been so much crap floating around the Internet talking about the weakness of D30 4.88 gears.

It is NOT necessary to upgrade the whole front axle if someone is concerned about component strength. It is fine to run 4.88's in a D30. D30's can be upgraded to 760x axle u-joints to increase strength. The axle u-joints can be installed using snap rings rather than c-clips to increase strength. Chromemoly axle shafts can be used to increase strength, and aftermarket u-joints can be used to further increase strength.

If you want strength, a D30 with allow shafts and aftermarket u-joints is virtually unbreakable with 33" tires.

 

[Rawbrown]

I'd only worry about a 4.88 gearset in a D30... Maybe and a big maybe, if its a LP TJ D30. I have firsthand experience with a busted LP D30 because its out in the garage waiting for me to put new gears in. 3 ring gear teeth are busted off.
with 35" tires and a slushbox. Thats my first gearset to fail on the trail.
has anyone seen a busted HP D30 gearset?
As Goatman said, be more worried about popin a shaft that a gearset.

 

[HaZakated]

and I'm not quite following how your getting your roll over forces or pressures. It wouldn't require dropping off a 100' cliff to get 50ksi and 15ksi is pretty light, maybe a slow flop. A hrad roll can easily genrate 50ksi and of course that depends how much area it's spread over so really me should be talking about forces not pressures.

Is the above statement accurate information?

I recieved my information from one of my mechanical Engineering professors here at Miami University that does some mild off roading. I wasn't speaking literaly when using the 100' cliff...just as an example.

 

[Roxtar]

The idea of strength difference between a 4.56 and 4.88 has nothing to do with shaft size.
It's due to the fact that the lower (neumerically higher) the gearing is, the fewer teeth there are on the pinion gear.
That mean less contact area which creates higher stress on said contact area, IOW, broken teeth.
A D30 already has a very small number of pinion teeth and would be more suseptable to this problem.
That said, I don't think there is much real world evidence to show more actual failures in 4.88 than 4.56 gears.

 

[HaZakated]

I understand exactly what you are saying. I was just pointing out that there is a way to calculate the strength difference between the two gearsets. Your first post made it sound impossible. I don't care what you said about significant differences, I was simply stating that you can determine the difference.

In this situation it's not necessary though since you will likely break a 4.56 just as easily as you will a 4.88.

What I'm saying is; if you know what you are doing, you can calculate the amount of input torque (within a range) a gearset can handle.

If that is the case, I appoligize. I misunderstood you.

 

[HaZakated]

It is amazing how much non-information has been posted so far in this thread.

Get the ratio that you think is best for your gearing. There has never been any evidence posted on this topic to show that the 4.88's are weaker than the 4.56's. Never anything other than conjecture. Not even personal experience. The difference between 4.56 and 4.88 isn't very much. When considering strength, the increased rotation and leverage have to be considered along with the tooth contact area, so there could easily be no difference in strength whatsover. Jeeps used to come stock with 5.38 gears in D25/D27 which is the same gears as a D30, and they were standard cut, so arguably not as strong as the reverse cut XJ D30 gears.

Get what you want, and don't worry about it.

What is the non-information that you refering to just out of curiosity?

 

[Goatman]

What is the non-information that you refering to just out of curiosity?

You're a brave man asking that question.

As a possibly productive excersize for other newbies, I'll indulge you with an answer. Bear with me here.

I doubt that there is any significant strength difference between the two gear ratios. Its like comparing apples to oranges (You cant). What gearing boils down to is getting the power from the moter to the tires. As you get bigger tires, your XJ will loose power to the tires. This is not to say the power is not there, im just saying that if you dont regear, you won't be able to harness the power that your XJ has. Regearing allows you to harness that power again after putting larger tires on.

I run 32" tires and have no power issues at all. I know that if I ran 35's, I would need to regear. When I go to 33's, I will most likely regear to 4.56's. 4.56's and 33" tires are a good (on road/off road) combination for those who like to wheel the blue trails(Intermediate) and use thier XJ's for a daily driver as well. The only problem with doing this is that if you want a multitask off road vehical, you will never have the best of either world. However, I am willing to make the sacrifice until the old (2000) XJ becomes a beater (In a year or two).

4.88 gears would be the way to go with 35" tires according to calculations; however, strength may be an issue with your Dana 30. That Axle will not take much abuse with 35" tires and 4.88 gears. You may want to think about upgrading your axle before going to 35" tires. You may be able to find a cheap D44 already geared low for cheaper than regearing your D30 and exsisting rear axle.

This whole post has nothing to do with the question which was asked, the question was about comparative strength between the two ratios.

I didn't know that there was much of a difference between the two. Atleast no significant difference in strength. I suppose that one could have the pinion hardened making them stronger. But Why? the material is already strong.

Getting the pinion hardened? You don't think a set of gears is already hardened? Where would you go to get this done, if it was to be further heat treated? Obviously no knowledge (non-information) about the subject.

What does strength have to do with regearing though in this situation? 4.56 vs 4.88

I think he is new and is a tad bit confused. Thats why I explained it. Hey, I learn something new everytime I get on here. The least I can do is give a little back.

I think you have the wrong person new and confused. The original poster asked a legitimate question based on Internet rumor. You know less about the subject than the guy who asked the question.

In this situation, I believe that this guy is new to XJ's and simply stated his question in a manor for which made sense to him, but not to long time XJ enthusiasts.

Mabey I am completely crazy in making this assumption, but I think he should be more concerned with wasting his money than worrying about the strength between 4.56's and 4.88's. If he gears to 4.88 and goes to 35" tires and starts breaking axles left and right, he will have to spend more money on axles than what he could of spent just buying a set of dana 44's already geared low.

Brian

Again, the question about strength difference between 4.56 and 4.88 gears in a D30 has come up many times before. It wasn't asked because he's new to XJ's, and it was asked in exactly the right way.

About wasting money, do you have any idea how many people are successfully running D30's with 33" and 35" tires? We can talk in another thread about equiping a D30 to last, but this thread was simply about gear strength.

3 tooth contact with 4.56's. 2 tooth contact with 4.88's. That is why the are said to be the weakest gearset for the Dana 30.

There is a 6.6% difference between 4.56's and 4.88's. Not very much. I don't have a D30 ring and pinion sitting here so I can count the teeth, but this means there should be one tooth difference in the pinion........not exactly a 1/3 difference in tooth contact.

Call up dana ask them.... there is very little difference in gear strength. that is the point in using hypoid gears you can change ration and still keep strength. as for the pinion gear size issue. well it is a non issue as the weakest part much like splines on a shaft is the smallest diameter on the part (the pinion shaft). the most important part of any gear set is that it is installed properly most breaks are caused by improper setup or housing flex not a weak gear.

Some truth, some bad info. The weak point is the gear teeth themselves, based on experience. I've seen (and heard of) numerous D30 ring and pinions with broken gear teeth, have not seen a pinion shaft break.

 

[HaZakated]

In all my posts I tried to stay as far away from detail as possible. I did this because I knew that I do not know alot about gearing except for the bold print....Power to tires, power to tires.

If I made a bad assumption, I appoligize; however, nothing about this post has led me to believe that the guy wasn't confused.

Sir, I quite simply tried my best to give this guy what information that I had.

Futhermore, It sounds like you know alot of stuff Goatman. I wish I could be as knowlegeable as you one day. Thanks for making me feel retarded brother. Mabey one day I can look down on people the way that you do. Thanks. You are a smart man.

There's a little lesson in Psychology for ya. Sucker.

 

[Roxtar]

In all my posts I tried to stay as far away from detail as possible. I did this because I knew that I do not know alot about gearing except for the bold print....Power to tires, power to tires.

If I made a bad assumption, I appoligize; however, nothing about this post has led me to believe that the guy wasn't confused.

Sir, I quite simply tried my best to give this guy what information that I had.

Futhermore, It sounds like you know alot of stuff Goatman. I wish I could be as knowlegeable as you one day. Thanks for making me feel retarded brother. Mabey one day I can look down on people the way that you do. Thanks. You are a smart man.

There's a little lesson in Psychology for ya. Sucker.

That was just stupid.
If you knew Goatman, it was stupider.

 

[Goatman]

In all my posts I tried to stay as far away from detail as possible. I did this because I knew that I do not know alot about gearing except for the bold print....Power to tires, power to tires.

If I made a bad assumption, I appoligize; however, nothing about this post has led me to believe that the guy wasn't confused.

Sir, I quite simply tried my best to give this guy what information that I had.

Futhermore, It sounds like you know alot of stuff Goatman. I wish I could be as knowlegeable as you one day. Thanks for making me feel retarded brother. Mabey one day I can look down on people the way that you do. Thanks. You are a smart man.

There's a little lesson in Psychology for ya. Sucker.

Oh, if I was trying to make you feel retarded, I could have done a lot better job of it than I did. I was being nice about it. BTW, if you're talking about a psychology lesson, I can't make you feel anything.....

You asked the question. If you didn't want an answer, then don't ask the question. As far as knowing a lot of stuff......I make a point to only answer topics that I have knowledge about. If I don't know, then I don't answer. You made the mistake (as plenty of others around here do also) of trying to answer a question that you know nothing about the topic, and further more, you know so little that you didn't even understand the question, and after reading this thread you still don't. (how does that make you feel?)

As far as looking down on you.....how about these comments of yours? I at least know what I'm talking about.

I think he is new and is a tad bit confused. Thats why I explained it.

AND

In this situation, I believe that this guy is new to XJ's and simply stated his question in a manor for which made sense to him, but not to long time XJ enthusiasts.

Brian, sit back and relax, and keep reading. Besides calling me a name, you seem to have a decent attitude, and you aren't afraid to admit a mistake. Stick to commenting on things that you have first hand knowledge about and you'll do fine.

See ya around,

 

[Weasel]

Is the above statement accurate information?

I recieved my information from one of my mechanical Engineering professors here at Miami University that does some mild off roading. I wasn't speaking literaly when using the 100' cliff...just as an example.

Back the numbers up and find the forces or deacceleration that each would give. If contacted over a 1.25" tube with a 1" section, then the 50,000psi load would result in about a 20g deaccleration. 15000 psi would be about a 4 g deaccleration. In a hard endo flop, or side flop, 20g is easy to exceed. Not to mention a roll while desert runnning. A very slow mild flop into a soft surface is probably a pretty low deacleration though. So designing for a 50,000 pis force might not be a bad idea. Of course the more area then the greater the deaccletion. F=ma, P=F/A it's fine to get numbers from people but try to think through them and see if they make sence.

 

[CaliGold]

I think you guys scared off Igorman00 (original poster). I'll go back to hiding under my Jeep now...

 

[lgorman00]

i'm still reading you old time XJer "experts" hash out the truth.....i guess.

So keep posting so i can make a descision... KEEP UP THE ARGUING

 

[Roxtar]

KEEP UP THE e-Drama entertainment

Fixed

 

[HaZakated]

taken back

 

[HaZakated]

Back the numbers up and find the forces or deacceleration that each would give. If contacted over a 1.25" tube with a 1" section, then the 50,000psi load would result in about a 20g deaccleration. 15000 psi would be about a 4 g deaccleration. In a hard endo flop, or side flop, 20g is easy to exceed. Not to mention a roll while desert runnning. A very slow mild flop into a soft surface is probably a pretty low deacleration though. So designing for a 50,000 pis force might not be a bad idea. Of course the more area then the greater the deaccletion. F=ma, P=F/A it's fine to get numbers from people but try to think through them and see if they make sence.

I stand corrected then. Professors here are not always correct.

 

[Roxtar]

"stupider"......kid, I have no desire to know him. Back off!

Yes, that grammar faux pas was intended.
Back your own punk-ass off.

 

[HaZakated]

Oh, if I was trying to make you feel retarded, I could have done a lot better job of it than I did. I was being nice about it. BTW, if you're talking about a psychology lesson, I can't make you feel anything.....

You asked the question. If you didn't want an answer, then don't ask the question. As far as knowing a lot of stuff......I make a point to only answer topics that I have knowledge about. If I don't know, then I don't answer. You made the mistake (as plenty of others around here do also) of trying to answer a question that you know nothing about the topic, and further more, you know so little that you didn't even understand the question, and after reading this thread you still don't. (how does that make you feel?)

As far as looking down on you.....how about these comments of yours? I at least know what I'm talking about.

You took my quotes out of context. Thats illeagle...Joking.

When I made those comments, I really wasn't trying to look down on anyone. I was trying to explain that if I can help (Which no one was in this situation), I will do my best. If I answered the wrong question, like I said, I appoligize; however, I still believe that he was confused.

Let us analyze his thread title and first post.

(first post)
"what are the strength difference between 4.88 and 4.56 in dana 30.
Is it better to stay with a 4.56 with locker for 35" tires"

(Thread Title)
"Strength difference between 4.88 vs 4.56 gears"



You know what....it is entirely possible that I am completely wrong. I never thought to look through his previos posts till just now.

I appoligize to everyone. No shame. My mistake was assuming that he was extremely new. As far as the sucker thing, you did fall right into my trap....lol
Atleast I accomplished some thing. (This is my way of dealing with being wrong....deal with it!)

 

[HaZakated]

taken back....no sense in this childish crap.