Re-gearing a Rubi. for 35's

[Wayco]

My new Walker Evans bead locks are on with 35" Pro-Comp Xterrains. Next week I will be back at 4 Wheelers spending more money..:D
New alloy axles and gears, the problem is that I can't decide if I want to do 4:88 or 5:13... :confused:
I still like to drive fast but don't want to be revving the engine over 3000 rpm just to do 80 mph.
Does anyone have advise or knowledge about what I could expect with either of these ratios?

[1BLKJP]

Do you have the 4 speed auto or 6 speed manual?

[Wayco]

Sorry, I thought it was in my sig. 6 speed manual with the 4 in 1 Rubi. T-case.

[michale r varne]

Wayne, I have 4.88's and i can't see going any deeper than that, unless you are going to trailer your rig. At 60 mph I'm turning around 2500 rpm. To get it around 70-75 a little over 3000 rpm. We have the same jeep pretty much (6 speed manual, same tires), if you want, give me a call and you can run my jeep down the highway. I know guys on ROF with auto's like 5.13's.

[michale r varne]

PM sent

[neZZr]

Unless you plan to go even bigger, I'd go for 4.88. If you're still running the stock gears with your 33s now, you should find that the 4.88/35 combo will work even better.

[desertfabmotors]

Go with 4.88, At 1:1 you will be around 2600 rpm at 55 MPH.

Also remember, the lower in gear ratio the weaker the gear.

[1BLKJP]

Yeah, Wayne, I agree with the fella's on the 4.88's with the 6 speed. If you had the auto then the O/D would turn your RPM's down quite low at higher speeds with 5.13's.

[T.C.'S TOY]

Wayne ! go the 488's i did and love em .....Thom (T.C.'S TOY):)

[AZG23]

yup Wayne....you will like the 4.88's...with the 4:1 T case itll be great on the trail, and not bad on the freeway....and most importantly...what Todd said..

[Simon]

x2-8 from above. :) You'll like em'.





p.s. How are the new shoes?

[YGOHOME]

guess I'm the only one who's going to vote for the 5.13s. Why would you want stock like performance, thats so booring. If I'm going to spend alot of money on new gears and the install then I want to get the best crawl ratio I can with the gears my carrier would allow. Its not like your going to be pushing redline on the freeway with the 5.13s

my jeep is a daily driver and i have the 5spd 35" MTRs and 5.13s. I had the 5.13s while I was running smaller 31-32" tires for a few months and was great then too. especially on the trail.

[Huck]

Wayne,
I run 4.88's with the 5 speed and Ben (YGOHOME) runs 5.13's with his 5 speed. I do a lot of road miles with my heep and really liked the 4.88's. I will say that 37's aren't too far off and I'm thinking that 5.13's should have been what I installed. Its a tough call, but I know several folks that are running 5.13's and 35's. They are all very happy with their purchase.

The way I figure it: People are forever posting up on the ROF and other boards about how they run 35's and their factory 4.11's. They say that performance is fine and that while offroading in 4low, all is great... Now, we all know that once you go to the 4.88's, then wheeling truly becomes a pleasure and your crawl ratios return. You also tell everyone you know running 4.11's and 35's that they have no idea what they are missing out on. I can only imagine that the person running 5.13's may have the same outlook.... Since I don't run them, I can only guess. FWIW-I know that Joe D only recommends running the 5.13's with 35's. It was too late for me, as I had already purchased my 4.88's prior to even considering the 5.13's.

Looks like Ben already responded, darn phone calls keeping me from typing.

[TinyMan]

Wayne, I'm with the majority go with the 4.88's, and that is what I have in my 05. Going down the highway is still good, and in 4 low and first gear still nice and slow, for what I do.

[xFallen]

I would forget about 5.13s in a 44. Go with 4.88s for pinion gear strength and the ratio will be adequate for crawling.

Even people with 60s are sometimes going no deeper than 4.88 for strength reasons.


Barry

[mingoglia]

I too would stick to the 4.88. I'm of the camp if you drive your rig on the street gear it for the street and do your gearing in your transfer case. It's the best of both worlds IMHO. In your case, with your Rubi, you have a 4:1 (I'm running 4.56 gears with a non-rubi and 35's). I also don't like to run the deepest gear in a given axle as you start getting to the point where you have less pinion teeth in contact with the ring gear not to mention you have a super thick ring gear and a puny pinion at that point.... the last thing is you can contend with heat in your transfer case but with the limited size/capacity of the differential running super low gearing at 80mph through the AZ desert going to the trail isn't the best combination... after all, there's a reason semi trucks typically have 3.55 or 3.73 gears... they run cooler and are stronger. Just my humble opinion of course... many here have 4,000X's more experience than poor me. :p

Mike

[mingoglia]

...well, looks like Barry got it typed faster than me. ;) Oh, and holy run on sentence. My grammar is typically better than that. Oh well, at work. Oh, and Joe will eventually join this thread and swear up and down all day long that he hasn't had any customers break 5.13 gears... and he does have the eperience to back that up... so once again, just my opinion but with all my experience towing I can at least vouchfor strength and dissipating heat in at least over the road vehicles.

[LOST TJ]

I put my jeep in 4 low yesterday for the 1st time with the new 35s and 513s and :eek: I could not believe how slow it crawled down the road without giving it any gas. It was amazing. I'm a auto whore though. I would still think you would want the 513s just purley for the trail performance. Are you more interested in the road performace or off road performace. Your 1st gear is even lower than my auto. Think about how slow you could crawl on the trail and not how fast you can go or hi rpms on road. It seems most things that improve trail performance tend to degrade road performance. Jmo BWTFDIK

[mingoglia]

I put my jeep in 4 low yesterday for the 1st time with the new 35s and 513s and :eek: I could not belive how slow it crawled down the road without giving it any gas. It was amazing. I'm a auto whore though. I would still think you would want the 513s just purley for the trail performance.
Are you more interested in the road performace or off road performace. Your 1st gear is even lower than my auto. Think about how slow you could crawl on the trail and not how fast you can go or hi rpms on road. It seems most things that improve trail performance tend to degrade road performance. Jmo

One thing to note though is although his first gear is lower than yours and auto isn't affected by taller gearing as much as a manual due to your torque converter...and of course lack of a clutch...

[82NOME]

I am running 5.13 Alloy gears and axles w/ a 5 speed manual and love it. I must state this is trail rig and not a DD. My http://i167.photobucket.com/albums/u153/82nome/Emotioncons/twocents.gif

[LOST TJ]

One thing to note though is although his first gear is lower than yours and auto isn't affected by taller gearing as much as a manual due to your torque converter...and of course lack of a clutch...

You caught me while i was adding. "BWTFDIK" :D

[YGOHOME]

I would forget about 5.13s in a 44. Go with 4.88s for pinion gear strength and the ratio will be adequate for crawling.

Even people with 60s are sometimes going no deeper than 4.88 for strength reasons.


Barry


aren't you running a cryo d30? maybe just cryo the 5.13s in the 44 if that a concern

[mbuckner]

I have a set of Yukon 4.88's in the garage expecting
to install when I got my 35's ...... but after driving with
4.56 gears & 35's, I am not going to change .. Instead,
I will go with a TeraLow ....... I like high range gearing
now ....

My 2 cents .......

Good luck,

Mike

[Wayco]

Thanks for all the comments gang. I think that the majority are for the 4:88's, but that's not the only reason that I have decided to go that route. Strength is important, I am trying harder lines now and with the 35" tires it will only provoke me to go on the harder trails. That being said, I still want to keep up on the freeway getting there. So until I decide to trailer it, I think that 4:88 will be the ticket.
Now what about breaking in the gears? Mike at 4 Wheelers gave me a sheet with some guidelines, but I lost it, he was saying it's no big deal. Just warm them up a few times and let them cool off for 30 minutes... Is it different for different gears?

[4 Wheelers Supply]

4.88's

[FlexyXJ]

Good info, But who drives around in 4th gear, when you have a 5 speed or a 6 speed.:confused:


Joe


Go with 4.88, At 1:1 you will be around 2600 rpm at 55 MPH.

Also remember, the lower in gear ratio the weaker the gear.

[lancetkenyon]

Wayne, if you HONESTLY think you will stay with the 35s, do the 4.88s. If you HONESTLY think you MIGHT go to 37s, run the 5.13s.

[joedokes28]

Something to note.

1st gear in the 6spd is lover than 1st gear in the 5spd. 4.46:1 vs. 4.04:1. In my opinion, this would justify 4:88's in a 6spd rubi and still being able to maintain a good crawl ratio.

NSG370 ratios (6 speed)

1st - 4.46
2nd - 2.61
3rd - 1.72
4th - 1.25
5th - 1.00
6th - 0.84

Rev - 4.06


NV3550 (5 speed)

4.04:1 - 1st
2.33:1 - 2nd
1.38:1 - 3rd
1.00:1 - 4th
0.78:1 - 5th
3.57:1 - reverse



I am currently running 35's on the stock 4:10's and it's OK off road and it sucks big time on the highway. I'll be going to 4.88's in the near future.

[Wayco]

x2-8 from above. :) You'll like em'.





p.s. How are the new shoes?

Driving home was interesting, didn't have to use 6th gear! I'm taking them off for this weekend, the crawl ratio is just wrong. :( I think I am scheduled for gears and axles on April 4th, did you guys get the axles in yet?

[4 Wheelers Supply]

Driving home was interesting, didn't have to use 6th gear! I'm taking them off for this weekend, the crawl ratio is just wrong. :( I think I am scheduled for gears and axles on April 4th, did you guys get the axles in yet?

They claim they shipped yesterday.:)

[xFallen]

Wayne, if you HONESTLY think you will stay with the 35s, do the 4.88s. If you HONESTLY think you MIGHT go to 37s, run the 5.13s.

4.88s and 37s are almost perfect on the highway with the I-6. 80 mph no worries and the speedometer is pretty close. Remember, he has 4:1 so with 4.88 he'll have a decent CR.

[xFallen]

aren't you running a cryo d30? maybe just cryo the 5.13s in the 44 if that a concern

Yes, the D30 is cryoed but who knows how much it will help. There's no real way to prove it helps because in this case there's no scientific nor controlled comparison. It is an experiment.

Presumably it won't hurt, but there is such a thing as making metal more brittle and therefore more fragile even if it is harder. This is why manufacturers often do not use 4340T in some axles and instead use 1540H.

Either way, the 5:13 pinion on a D44 is very small and I think too small for extensive abuse with some degree of longer term reliability.

I'll be running 4.88 in my D60s for the same reason, even though 5.13 in that case is probably okay. I have heard of people going to 4.56 in the 60s for strength reasons. Makes a lot of sense.


Barry

[desertfabmotors]

Good info, But who drives around in 4th gear, when you have a 5 speed or a 6 speed.:confused:


Joe


It was info provided at 1:1 so it gives an idea of RPM. Yes you can go lower if you have a 5spd or 6spd, but like I said the Lower the Ratio the WEAKER the gear.
There are you still confused!!:rolleyes:

[YGOHOME]

THere was some concern that the 5.13s were considerably weaker than going with a higer gear (numerically lower). I got these photos from a recent thread on the ROF...
---------------------


In these first two photos the 5.13 ring and pinion are on the right. The teeth seem bigger ...5.13 vs 4.10:

http://i23.photobucket.com/albums/b385/damonr/513%20gears/DSC04791.jpg

The physical size of the pinion is smaller, but the teeth don't look vastly different than the OE. Here's the ring:

http://i23.photobucket.com/albums/b385/damonr/513%20gears/DSC04789.jpg

-------------

Thanks for those photos Doctor D... would you be able to take a photo of the 5.13's vs 4.10 ring side profiles?
Thanks,

Ben

http://i23.photobucket.com/albums/b385/damonr/513%20gears/DSC04793.jpg

In that photo the 5.13 is on the LEFT... 4.10 is on the right

They're not weaker.

- Doctor D
---------------

[SavageSun4x4]

How often do you drive, in town and on the highway?

Tire size: 35/37 [using the GY MTR chart is 34.8" and 36.8" respectively, http://web.mac.com/donpryor/iWeb/SavageSun%204x4/Goodyear%20MTR%20Specs,.html ]

In the 35-37 range the 4:88 will provide you with excellent off road ability [35's] or OEM ability using the 37's. 37 x 4:88 = very near OEM of the Rubicon with 4:10s. in fact the speedo is almost dead on.

I run 37 MTR x 4:88s and am pleased with the performance. That said, if I had it to do OVER again I would have gone with 5:13's for 2 prime reasons.

1) Just a bit more lower gear in the rocks

2) A little better performance on the highway with no loss of mpg. In fact running in 4 th gear often gives me better mpg than in 5th at highway speeds, especially so when driving with increasing elevation...such as to Moab or North or West with a headwind. The 5:13 would let me get a little deeper into the torque band at highway speeds.

Gear strength: Albeit the 5:13 might display a little more weakness on a torque testing table, for our purposes the difference is nil to none. We are crawling rocks not doing 7,000k RPM banzi starts on the "1320". This is especially true if you stay in the 35-37-39 tire range. Bolt on 42's and plus up your engine HP/Torque to twist them then you might encroach on the strength of the 5:13's...maybe.

Bottom line: 4:88 will most likely satisfy your needs and purpose, especially if you stay 37 or less in tire size.

[joedokes28]

I have held the pinion from a 4.88 gear set and the pinion form a 5.13 gear set side by side and they are both 8 tooth pinions and look identical. I believe the differences are in the ring gear.

Knowing this, I'm not exactly sure how the 5.13 pinion can be weaker that a 4.88 pinion.

[SavageSun4x4]

I have held the pinion from a 4.88 gear set and the pinion form a 5.13 gear set side by side and they are both 8 tooth pinions and look identical. I believe the differences are in the ring gear.

Knowing this, I'm not exactly sure how the 5.13 pinion can be weaker that a 4.88 pinion.

In this case its 8 teeth per pinion, and 39 Vs 41 teeth per ring gear, 4:88 and 5.13 respectively.

If the size of the pinion is the same, the somewhere you have to add more teeth to give you your ratio of 5:13. That happens on the ring gear and if the pinion remains the same size the the ring gear has to change sizes, in this case larger since we are squeezing in 2 extra teeth and still maintaining the same contact patch, pinion to ring gear.

The rub is that the carrier only comes in two sizes. Generally speaking carriers support ratios from 2.xx - 3.xx and 3.xx - 6.xx. The break point is most often somewhere around 3.73 - 3.90. Ratios will range from 2.92 - 6.14 depending on the axle assembly and who it was manufactured for.

Ideally the carrier would be built to mate to what ever size the R&P ratios are. But cost keeps that from happening. Instead a common set of bolt patterns mate up R&P to carrier. With differences being in width and size of R&P. So some compromises must be made.

The pinion will begin to get smaller and the ring get thicker in order to mate with one another.

In this case size does matter and along the path size affects strength or its ability to handle xxx lbs of torque.

The question of strength or lack thereof really only raises its head as you begin to operate at the limits of the setup. As I said earlier bigger tires need bigger hp/torque to move them and the diameter of the larger tires acts like a lever by putting more torque on the axle, u joints, shafts, tube, carrier and R&P.

I doubt many of us here will push the limits of most of our rigs, but some will. That said one might mitigate axle damage by running smaller drive-shaft u joints to act as a "fuse" in the chain. Besides being able to swap a DS u joints in less than 15 min trail side.

Bottom line there is very little difference between 4.88 and 5.13, some no doubt, but for our purposes not enough to worry about.

NOTE: Its is far more complex than my short points on this but I think you get the picture.

[YGOHOME]

i get the picture... its about 3 or 4 posts above. ;) The 5.13 looks plenty strong to me when compared to stock 4.10s

[lancetkenyon]

What about 5.89s???

[YGOHOME]

What about 5.89s???

5.89's in what? :)

anything numerically higher than 5.00 is made from paper. just joking of course. WIsh I had 5.89s