5.38s for a ford 8.8?

[HeavyMetal]

ya i know justin's rig was trailered and the nature of all that. now it was my understanding that if youre seeing street time or anything for that matter it would not matter what ratio was in the axle that was not engaged (ie using 2wd on the road).

correct. i drove around for a month or so with 4.56 rear 3.55 front when i regeared way back when (2wd)

if it were my jeep (trailriding/multipurpose) theres no way i would span it between 4.88 and 5.13 or 5.38 for actual use though.

the "acceptable" practice with it is within .02 for the sake of parts. i mean, could you get away with it? maybe...but is the risk worth the reward? i say not even close...your tcase and driveline will thank you..also you wont have to hassle with constantly switching between 2wd and 4wd to "save" the jeep. like zullo said, consider the tcase differences..among other things

and frankly, I dont think youre gonna care about the difference between 4.88 and 5.13, it really isnt that much of a difference performance wise. its like the 4.56 to 4.88 debate, people put way too much thought into numbers on paper and too little into real-world circumstances

oughta engine swap that bitch

[ninetysix-ex-jay]

Honestly, I wouldn't run 2 different ratios on 1) a streeted Jeep. 2) one with a D30. or 3) with a 231.

Unless you really feel like shifting it just to relieve the extra pressure its putting on your chain driven t-case I honestly see no valid point in doing this for a vehicle that sees 90% street use

[konastinky1234]

ya risk seems like it will not be worth the reward after all this. guess i will just go 4.88 and hope for the best. maybe down the road a 44 will be in order to gear deeper. however if this is tolerable i would not.

[CntStpTheStnk06]

Engine swap!!!!

[customcreationsllc]

The 9" using 8.8 gears are only for the Currie High Pinion 9" drop outs all the low pinion 9" use 9" gears. High 9 uses custom gears you can only get them from high 9.

5.38 vs 5.13 is only 5% difference
You should keep the rear geared higher (slower).

I checked ring-pinion looks like your stuck at 5.13

I run 5.38/4.88 which is 10%
Adam ran 5.38/4.56 for a while until the axle blew up chain reaction I think it started with the axle shaft. but wend to 5.38/4.88

Slow crawl is fine high speed like road you want them closer together.
there is some discussion on pirate about it but not much a couple KOH guys ran split ratios. A lot of mud racers also run split ratios.

If you have a 242 you can run full time on the road with no issue.

Basic theory going straight all the tires want to spin the same speed. when turning the front spins faster also the outside wants to spin faster (reason for open diff and all wheel drive)

Draw a little picture I have an 86" wheel base my front tires steer to 40º I assume the center of the axle as rotation connect the rear axle line to the front the front is about 12% longer I made little picture but cannot post it at work. I can e-mail it to someone to post for me it is really simple. Just a right triangle steering angle and wheel base then you can use math to get the other 2 lengths the difference is the ratio you need to steer at that angle. So when parallel you need both ratios the same.

So when turning the front wants to spin faster so I geared my jeep to allow that to happen actually at the T-case it is neutral (drive shafts want to spin the same speed) when steering but when driving straight it is binding up.
If the axle are geared the same then when going straight the T-case in neutral but when steering they bind up.

Since rock crawling is a lot more steering then going straight I think it works better.


Also in 2wd absolutely no issue

I started with 5.38/5.38 and went to 5.38/4.88 and I steer the same in 2wd as I do in 4wd. On my race buggy I'll probably go with 5.38/5.13 split the middle. but we'll see I might just run what I have.


Sometimes you need to think outside the box.
~Justin

[HeavyMetal]

well he def doesnt have a 242 in his tj lol

all things considered, outside the box is in my opinion a great mindset..however with a trailriding TJ on 35s with stock axles and a 231 tcase...you oughta avoid playing with fire

[customcreationsllc]

I felt like running the numbers. Wheel base doesn't matter it cancels out, it is just based on the steering angle.

So the percent gear ratio difference is

1-1/[(cos(90-steering angle)*tan(90-steering angle)]

Sorry I don't remember my trig enough to reduce the equation any further.

so steering at 30º you should get 15% difference in front to rear ratio

[customcreationsllc]

well he def doesnt have a 242 in his tj lol

all things considered, outside the box is in my opinion a great mindset..however with a trailriding TJ on 35s with stock axles and a 231 tcase...you oughta avoid playing with fire

I don't know what his build plans are.

Basically I was just stating where I came up with running the different ratios.
Thought that was the question.


Note:
Adam runs a D30 in his XJ but has RCV shaft and the D30 is welded 5.38 rear 4.88 front not a lot of hours but very hard ones.

[Zullock Holmes]

your mathematical deductions make sense to me.

I still think that this setup is really more benficial for competing, where front digs are either not allowed or you don't have the ability (tcase wise) to do it.

I just assumed a higher level of stress on the driveline components; front axle, tcase, etc.

Basically the way you put it i see a sensible and costworthy alternative to buying a twin sticked transfer case and cutting brakes. On the contrary though, if i'm out trailriding i don't mind having to back up and make 3-4-5-6 point turns, but as you know in competition though, every one of those backups is a penalty.

I just think the benefits are outweighed by the added strain, esp. on dana 30 u-joints with a locker and 35" tires. At that point RCV's would be a good way to go, but then all that load just transfers to the ring and pinion and lets face it, 4.88 pinion is TINY.

[konastinky1234]

i feel like the two options are both viable for this.

justin, build plans are a trailriding tj that also does a lot of DD

here's what i got under it:
hp30 front
8.8 rear
231

this is what i plan on keeping for the life of the truck. those components can handle anythign i will do in my opinion especially since i have a small engine and pussyfoot everything.

in regards to when you say trailriding is mostly turning i would have to agree and disagree. i imagine half the time ill be climbing straight up an obstacle, the other half turning while climbing or simply going over. i assumed that climbing an obstacle with the fronts pulling a little faster would be alright and not cause enough binding stress to break anything. when steering obviously there is no problem since you are neutral at that point.

i understand the traiangle picture thing i remember you explaining it to me way back and that makes perfect sense. so if i am ok while steering (neutral) and a little bit of bind at straight driving only for obstacles where i need 4wd i would assume it would be ok. also the way i see it is what about the amount of bind that you get when turning with the same ratios? not sure if this is a valid point but say if you are turning/straight 50/50 it would be and youd end up with the same amount of bind anyways. i can remember constantly having my tires scraping over the ground while in 4wd this summer while turning, which is binding all my components so thats why i would say youd be safe.

now obviously if i were to drive around rausch for 3 days in 4wd with this i could see there being problems at a point but with low traction dirt and the tires pulling and scraping over everything losing traction etc i would think the bind wouldnt really kill you. to alleviate this i would simply use 2wd for everywhere besides the tough crawling trails hence the reason for a 2lo fork for my case.

obviously my last concern is pavement since i would never be stupid enough to use even 4wd with the same ratios on anything near high traction on the road. i would use 4wd when i needed it in deepish snow and driving slow. there will be no high speed in this equation unless i am in 2wd.

also what is RCV shaft?

anyways this is just my personal take on it after taking both opinions into consideration. im kind of torn here honestly since i really want better on road ability to handle the highway since i enjoy driving my jeep everywhere and i want it to be all purpose which is attainable with my setup. at this point i have to lean more to the side of using 4.88/5.13 just because i feel that after all things taken into consideration i think it would work out especially since i am very conscious of shifting the tcase.

now before i go ahead and make my choice (which isnt going to occur until the spring) i am going to go ahead and install my 35s on there with the 4.10s still in, test drive just to see what its like, install hp30 with the 4.88s and spider gears and do a day of test driving in front wheel drive by just taking off my rear shaft to see how the 4.88 powers the truck. after that ill make my final decision as to what i will do. if 4.88 is adequate enough i would probably go with that to be honest since i then have no worries whatsoever. if it is too doggish then i may decide to try the split. but again like you said will, the difference is small so i will have to consider that as well.

i have calculated my power and on my setup now(4.10 on 31s) vs the new setup(4.88 on 35s) i will be about 100 rpms higher which gives me slightly more power with the new setup(4.88 35s).

the sole reason for split ratio with a deeper rear for me is better highway capability, that is it. ill have to consider that too especially since in the end i could just never use 5th gear and that would probably compensate my difference..........

4.88s would probably be the smarter choice in the end but if i could do 5.13 rear i would like to.

thanks for all the input and advice guys i really appreciate it. let me know what you think about the opinions i had about using the split ratio in the trails because i want to know if that is rational and what not for my own experience.

[HeavyMetal]

thanks for all the input and advice guys i really appreciate it. let me know what you think about the opinions i had about using the split ratio in the trails because i want to know if that is rational and what not for my own experience.

All i have to offer moving forward

http://www.google.com/search?rlz=1C1...front+and+rear

[Dizzaster]

This thread makes me want to kill baby seals...

[konastinky1234]

guess we will just put it to rest then. thanks for the advice and everything guys.