HaZakated said:I doubt that there is any significant strength difference between the two gear ratios. Its like comparing apples to oranges (You cant).
The Blu Yak said:The pinion gear doesnt really become effected strength wise till way up in the gear ratio.
IntrepidXJ said:i think he's more concerned with the size of the pinion and ring gear teeth between the two sets
HaZakated said: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.
goatman said:There is nothing to be concerned about with 4.88 gears........the fears and negative comments are unfounded. It's like global warming......propagated by people who don't know based on what they've heard, which came from someone else who didn't know, but spoke on what they'd heard....and on and on.
IntrepidXJ said:well, 4.88 is the top for a d30....so that would be "way up in the gear ratio" for that axle
HaZakated said:I doubt that there is any significant strength difference between the two gear ratios. Its like comparing apples to oranges (You cant).
Dirk Pitt said:You can most certainly determine strength differences between gearsets.
It is a long, drawn out set of equations, that most would become frustrated with before ever reaching the end.
HaZakated said:take a glance at the {key} word in my first post......("Significant").........I know that the strength would vary slightly because the cut sizes are different between the two gears. I just don't think that it is enough to make a great difference. Mabey the apples to oranges phrase was a little 2 far. More like apples to apple trees...lol
What do you think about when you hear the word strength?...I think about tensile strength, modulus of elastitcity, Shear strength, Yield strength, Impact strength...etc, etc. I listen alot here on . I usually stay to the side and just listen instead of speaking. I find that when I speak, there is always someone out there who makes it thier duty to prove me wrong. I see no sense in this. 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.
I am an advocate of learning from others mistakes. In most situations, I would have never said a word. In this situation I said a few. I hear people all the time talking about how they have to upgrade this and that if they want to do this and that. I am an advocate of overkill; however, Too much overkill is not nescesary. For example: There is no point in spending 5000$ on caging an XJ that will withstand impacts of up to 50,000 psi. That would be a waste of time and money unless you are just a very, very bad driver and plan on falling off a 100' cliff. I would estimate that on average, the maximum impact that an XJ undergoes in a roll over would be around 15,000psi.
What I am trying to say here is that in his situation, he need s more strength, but not from the gears, he needs more strength form the axle.
Have a great day.
Brian
HaZakated said: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.
lgorman00 said: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
bj-666 said: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).
Goatman said: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.
DaffyXJ said:Hold up a 3.55 pinion from a D-30 gear set to a 4.88 Pinion from a D-30 gear set and tell me there is no strength issues?