Gear ratios for new tires and lift

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CasterTroy said:
I've seen contrary. But, that's just my experience YMMV

This is just a 4.10 next to a 4.88

View attachment 11357

And I'm not even comfortable with 4.88

But again...that's just me. You be you :cool:
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You personally may not like 5.13 or even the extremely commonly used 4.88 but your worries about 5.13 are the very same worries and claims made by some when 4.88 first came out for the Wrangler axles. And we all know those claims and worries about the 4.88 gears were ultimately proven to be completely unfounded as self-evident by their many years of ongoing problem-free use. I personally have been using nothing but 4.88 since probably 2002.

5.13 was extensively tested in places like Johnson Valley (toughest wheeling in the US) by Revolution Gear well before they were released for sale. Circle K is who makes them for RGA and they are widely known as the very best manufacturer of R&P gear sets. And OF COURSE the pinion gear is going to be smaller with lower ratios, that's just how things work, but that in no way means 4.88 or 5.13 are not up to the job.

The bottom line is that your claims about 5.13 not being strong enough are completely and totally unfounded. 5.13 is already well proven in our axles including the Dana 30 and hardcore offroaders are not having any trouble whatsoever with them. Ask @mrblaine, he is well aware of the testing history of that ratio, I believe he was somehow involved in its testing.
 
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Can't we all just get along? The thread was started by Keston to find out about 33's, a 3" lift and gearing for a Jeep that would never see bigger than 33's and mostly street driving with a little mild off roading. Caster chimed in with some good points and a few great pics to illustrate the look that can be expected with 33's and some lift. Next thing you know Keston is no longer participating in the thread but a back and forth on gear ratio keeps going. :(
 
JP98 said:
Can't we all just get along? The thread was started by Keston to find out about 33's, a 3" lift and gearing for a Jeep that would never see bigger than 33's and mostly street driving with a little mild off roading. Caster chimed in with some good points and a few great pics to illustrate the look that can be expected with 33's and some lift. Next thing you know Keston is no longer participating in the thread but a back and forth on gear ratio keeps going. :(
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The problem is when someone starts making isolated claims about isolated failures, if they are even true, that are not supported by reputation or common knowledge. It is common knowledge, for example, that Dana 35 shafts will fail with 35's and lockers. We all know that happens. On the other hand, it is not common knowledge that Super 35 shafts fail with 35's and lockers. For someone to claim they do is, to me personally, like Caster Troy claiming 4.88 and even 5.13 gears commonly fail. They absolutely don't. There may be isolated instances but to infer those ratios aren't well proven to have a good reputation for reliability does a lot of disservice to those who don't know any better. Claims vs. the actual reality of the reputation of those ratios.
 
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The bottom line is that I'm asking you to back up your claims of problems with the 4.88 or 5.13 gears, simple as that.
 
I've been at the location of a 4.88 and 5.13 when the clicking and the crunching occurred. When they backed up it sounded like a a cement mixer full of gravel spinning.
Do I have visual proof by taking pictures? No. What would be the point? Unless they removed the diff cover in front of me.
Did I ever state this was common? No.


Just because you've not seen/experienced something doesn't mean it's never happened Jerry. I've never seen a million $ with my own 2 eyes, but I know it exists :cool:
 
CasterTroy said:
Did I ever state this was common? No.
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Exactly, it is in fact so uncommon that it's a non-issue which is why I'm not going along with your claims. Perhaps I should be on here claiming we shouldn't be driving Jeeps because I know someone who once had a problem.
 
RaymondT said:
The higher the numerical ratio, the thinner the teeth. And then there's the extra force the increased leverage puts on the ring gear.
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Ya'll small pinion head folks should start a club. Go look at the picture posted above comparing the two pinions. Now look at it closely. What do you notice? That's right, the teeth on the smaller pinion gear are actually thicker than the ones on the big one.

Now, you brought up force and leverage and I'm very glad that you did.

For the sake of discussion, let's take a feller with some big ole legs and lots of power and put him on 10 speed mountain bike at the bottom of a decent little hill. Start him up the hill in 10th gear. He's going to have to stand on pedals and get all his strength pushing down with one leg and try to yank the handlebars right off the bike to get it going up that hill. The pedals, and front sprocket are going to see very high forces.

Now have him shift it to 1st gear and do the same. He'll take off and scoot right up the hill sitting on the seat hardly working at all. Because he is pushing much less with his leg, the forces on the front sprocket are dramatically lowered because the leverage is now in his favor.

Pinion gears work the same way, the leverage is in their favor because they are smaller so for the same work potential, the forces are much less on the teeth.

Every gear company out there sells the lower gear ratios. They all offer warranties. If the forces that are involved didn't work the way they do each company would have a disclaimer that limited tire size or something or they wouldn't offer a warranty and just tell you to suck it up if you break them or they would quit selling them. They sell them, they warranty them, and the reason for that is simple, they just don't have a problem with them breaking that is related to the size of the pinion.

I see far more failed gear sets due to improper set up than I do for improper axle size for the terrain and tire size.

If you really want to understand a bit more about how the leverage is in favor of the smaller gears, find someone that will let you abuse their manual trans. Put it in 3rd gear and do a 3000 rpm clutch dump and watch what happens. It would be rare not to break something in the trans or blow the clutch. Put it in first and do the same and you'd be hard pressed to break anything.
 
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JP98 said:
I run 4.88 in my F & R Dana 44's but that is the limit for me. Going past that would be just asking for trouble.
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Not if you understand how gears work.

I have a TJ, 04, NOT normally aspirated. I drive it like a complete moron and I geared it to 4.88 with 32's. I never drive it that I don't do something dumb in it that would get me a ticket. The gears are just fine.
 
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CasterTroy said:
I'll continue to believe otherwise. If that's ok with you
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My signature most places is knowledge does not equal understanding. You have knowledge of failures, you don't understand why they happened. It's the old banana in the ear syndrome and goes thusly. Put banana in ear, look outside and notice that there are no alligators in the yard therefore putting a banana in your ear is how you keep alligators out of your yard. The empty yard is knowledge, the fact that one lives where it is too cold for alligators to survive is understanding.
 
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CasterTroy said:
I've been at the location of a 4.88 and 5.13 when the clicking and the crunching occurred. When they backed up it sounded like a a cement mixer full of gravel spinning.
Do I have visual proof by taking pictures? No. What would be the point? Unless they removed the diff cover in front of me.
Did I ever state this was common? No.


Just because you've not seen/experienced something doesn't mean it's never happened Jerry. I've never seen a million $ with my own 2 eyes, but I know it exists :cool:
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People do dumb shit and unless you watched the gear setter and know how he set them up and then went out with the rig every time it was driven, all you know is something broke, you don't really know why nor is there anything you can accurately attribute the break to.
 
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