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School me on 9" ratios

Since I was doing thirds today I had the opportunity to compare 5.40 mega hi gears to the new gearworks 5.43’s.(all high pinion) one thing that’s always annoyed me is that nobody on earth lists the count of pinion teeth and the amount of ring gear teeth. As builders that’s always one thing we base known strength off of, how many dam teeth are on that pinion.

MegaHi 5.40’s are 27 ring gear 5 pinion

Gearworks 5.43’s are 38 ring gear 7 pinion

That’s our last set of megahi gears, in a new GW case with the gearworks locker, and Tubeworks pinion support. I opened the locker to see what the insides look like before putting stuff together because I noticed it doesn’t have a cross pin. Didn’t look in anyway like I assumed. Should’ve taken pictures but I was busy and had rubber gloves on. This for the front axle in a 4500 class U4 car. I thought the GW locker was a better material Detroit but that assumption was wrong. Sort of works the same in principle but doesn’t have a single pin in it, inside it’s all gears and splines with two pissed off springs.

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Awesome stuff is the center "gear" of the ratcheting locker splined into the locker case half instead of the cross pin?

And on a similar note, Tubeworks put a very interesting post on FB today:

 
JR4X said:
I was editing my post when you made this one. Yes, re-read above.
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Nice, and very interesting additional notes. That sounds pretty similar to the 9" detroit overall (as you mentioned). I wonder if things are upscaled dimensionally on those internals
 
94toytruck said:
JR4X is that the Yukon service mount? Hows it holding up?
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Yes. And I love it. Once we got one, I’m pissed about wrestling them on the bench without it. If I only did one third every couple years it probably wouldn’t be worth it. Dad drilled the holes in the bench and it just lives under the bench when not in use. Bolt it down when doing thirds and it makes it so easy to flip it around anyway you need it but holds it tight when you need it held still.
 
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I been wondering about them for awhile, I usually wrestle them on a bench or bolt a plate to it and clamp it in the vise.
 
AgitatedPancake said:
Awesome stuff is the center "gear" of the ratcheting locker splined into the locker case half instead of the cross pin?

And on a similar note, Tubeworks put a very interesting post on FB today:

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A quick check on the black line, the torque to the carrier goes down as ratio gets higher.

I am curious about the units on torque. It looks like it may be N*m, which would knock torques down by 25%.
 
Huh, did not notice this little feature before.

Screenshot_20231231-084504_Chrome.jpg


I have mixed feelings about that retaining nut staying put.
 
bdkw1 said:
Huh, did not notice this little feature before.


I have mixed feelings about that retaining nut staying put.
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I bet that proves out over time not to work out. And if it doesn’t TW will correct course. They’ll probably have them in testing at KOH and all the desert races right away.
 
I would prefer a through shaft with a nut. Putting all the nose bearing loads on a nut just sounds like a bad idea. Jaysons a pretty fart smeller so I'm sure he has some tricks up his sleeve.
 
Huh I hadn’t seen that before either. I wonder if there’s an interference fit and/or a taper in play there. In one of their posts I saw them mention 300m shafting, don’t know if that was describing this application or not but interesting nonetheless.
 
They are doing that so if the third bearing journal is replaceble in the event the third bearing goes out. They have already been doing it as a repair for existing gear sets:
 
'84 Bronco II said:
They are doing that so if the third bearing journal is replaceble in the event the third bearing goes out. They have already been doing it as a repair for existing gear sets:
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We had to learn how to fix and combat that problem. It was gearworks that came up with the idea to go to all roller no cage pinion bearings. We tried it but it would torch that nub down. We’ve went back to the cage separated rollers to give space for oil to get in between the rollers because when the pinion is spinning 7000 rpm it’s centrifugally ran dry. Haven’t ruined a set in 4 years.
 
JR4X said:
As builders that’s always one thing we base known strength off of, how many dam teeth are on that pinion.
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Can you elaborate on why or how you determine a ring & pinion strength by number of pinion gear teeth?

MegaHi may have less teeth, but their teeth is noticeably larger.

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True Hi9

Get a Mega Hi9 delivered right to your home or business today.
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I might have misunderstood the context, but I interpreted it as the actual pinion head being detachable from the shaft beyond the snout bearing being replacable. The serviceable snout is super interesting on its own as well, though if they can actually swap pinion heads like it seems I would be shocked.

You can kind of see what looks to be a parting line under the inner pinion bearing journal on a couple of their renders, but not many actual pics show the same area



TrailTamer said:
Can you elaborate on why or how you determine a ring & pinion strength by number of pinion gear teeth?

MegaHi may have less teeth, but their teeth is noticeably larger.
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From the research I've been doing on gears lately, larger teeth (higher DP, or lower module) are generally stronger, but finer teeth run smoother.



From the above link:

"In general, choose a coarse pitch (lower numbers) for high torque and low speed, or a fine pitch (higher number) for low torque and high speed. Often one consideration that drives the choice of gear pitch is to keep the smallest gear above 12 or so teeth."
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"Using AGMA or ISO gear rating practices, you have two ratings for a gearset: strength and durability. Strength is the resistance to shearing off a gear tooth and durability is about contact pressure and resistance to spalling. Changing your pitch (assuming you're talking diametrical pitch) will bias your ratings more towards strength or durability.

Other factors that have been mentioned are noise. With helical gears, you have something called axial overlaps. The helix angle drives this, but DP does as well. Basically it's how many teeth are in contact at a given time. Higher axial overlaps can help reduce noise and vibration.

There's a lot to consider if you really want to dial into the finer points of gear design. I'd suggest starting with AGMA 2001 for a more complete look at gear design."
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"The bigger the gear tooth, the more torque it can handle. So really, the pitch is "decided" by the torque you need to transmit. Smaller teeth have smaller angular differences, and run smoother. 64 and 84 pitch gears are darned near silent. You can definitely hear the difference even between 64 and 48, and 48 and 32 pitch. Noise is wasted energy. :-)

Smaller teeth are more efficient.

Now, there's more to think about. Bigger gears can handle larger mismatches in gear alignment. That matters a lot! Especially for shock loading. You also can select between straight tooth, and helical cuts. Helical cuts help efficiency by removing most of the angular differences between teeth. Sadly, helical also makes the teeth more delicate as you get more point loading instead of a load across the tooth. That's why heavy duty transmissions tend to be straight cut gears."
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AgitatedPancake said:
From the research I've been doing on gears lately, larger teeth (higher DP, or lower module) are generally stronger, but finer teeth run smoother.
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Pinion gear (aka driving gear) 99% of the time is not the weak link.

Think a pipe you use as a lever to try move an immovable object. 1ft between pivot point and the immovable object, 5ft between pivot point and your hands (or feet), a 5:1 ratio. The portion between pivot point and the immovable object will break first, that’s your ring gear teeth in a ring & pinion scenario (assuming there was zero gear deflection).
 
TrailTamer said:
Pinion gear (aka driving gear) 99% of the time is not the weak link.

Think a pipe you use as a lever to try move an immovable object. 1ft between pivot point and the immovable object, 5ft between pivot point and your hands (or feet), a 5:1 ratio. The portion between pivot point and the immovable object will break first, that’s your ring gear teeth in a ring & pinion scenario (assuming there was zero gear deflection).
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Sorry, I got lost in my own thought process there. What I posted above would seem to imply that fewer teeth are stronger (as in the example you shared). But the anecdotal evidence from JR (which I've definitely seen repeated over the years) seems to have validity to it as well. Hmm
 
TrailTamer said:
Can you elaborate on why or how you determine a ring & pinion strength by number of pinion gear teeth?

MegaHi may have less teeth, but their teeth is noticeably larger
Click to expand...

I always feel like I’m too wordy and write novels with every post. I see my attempt at brevity left room for a lot of confusion

Nowhere will you find me saying MegaHi gears are weak, or weaker than anything else. We’ve built our race program around that diff since the day they started making Hi9’s. I’d be surprised to find out dad’s account isn’t one of their best customers. The mega hi gears were the best thing there was for a while.

What you will find me talking shit about is Toyota ring and pinion. There is no Mega or GW version of Toyota stuff. The lower the gear ratio gets In Toyota the less pinion teeth and smaller the pinion gets. On Toyota the pinion itself is the weak spot, a very pathetic weak spot. I think it’s a pretty common toy-ism that 4.56 is the breakover between what you can make live and what are too easy to break.

I posted the tooth count because people ask me all the time what the difference is. The annoyed comment comes from not having 5.38’s on hand to count teeth on, And googling that gets me nowhere because no mfg’s put in the details the tooth count. Again I am not saying megahi 5.40’s are weak, they are way stronger than 5.38’s. You know they are gone though right? Gearworks has US gear tied up. I’ve gotta replace the now extinct Mega’s with something and gearworks stepped up to the plate. I didn’t say 5.43’s with 7 pinion teeth are stronger than 5.40’s because of only having 5. You extracted that from nothing. That’s our last set of megahi gears because they are no longer available, not because we wouldn’t still buy them. Stay tuned for our builds when we’re trying to recycle our old megahi9 cases by putting GW 5.43’s in them. I don’t know how much grinding it’s going to take for a GW R&P to fit into a Hi9 case but I bet you money I end up in the situation of finding out.
 
I may have to disagree, 5.29s don't seem to really be any weaker than 4.10s. They're just all weak :flipoff2:

The biggest thing to make Toyota work, is a super tits setup. The guys that do that usually seem to have good luck with them, for what they are, a damn 8" r&p in mostly 5-6k lb rigs loaded for a trail (these days)



Anyway, I don't want to make this thread a Toyota debate. Has anyone actually had any luck going from say 5.38 to 4.56 or 4.10 to cure breakage issues? Because between me and my buddies, 5.29s to 4.10s didn't seem to really help with breakage. The only difference was 4.10s were cheaper.

I also know a guy who had an ls buggy with low pinion 60s and too big of tires. He bought it with 7.17s, broke them, went to 5.38 or 5.13s, broke those, went to 4.56 and broke those too. Haven't talked to him since. But my conclusion was that if you have an issue breaking gears, different ratios are not really a solution. And your money is much better spent on a bigger diff.

Edit: this may also apply differently to different axles. I've heard internet jabber that lower ratio 9" gears are stronger than higher ratio. :confused:
 
YotaAtieToo said:
I may have to disagree, 5.29s don't seem to really be any weaker than 4.10s. They're just all weak :flipoff2:

The biggest thing to make Toyota work, is a super tits setup. The guys that do that usually seem to have good luck with them, for what they are, a damn 8" r&p in mostly 5-6k lb rigs loaded for a trail (these days)



Anyway, I don't want to make this thread a Toyota debate. Has anyone actually had any luck going from say 5.38 to 4.56 or 4.10 to cure breakage issues? Because between me and my buddies, 5.29s to 4.10s didn't seem to really help with breakage. The only difference was 4.10s were cheaper.

I also know a guy who had an ls buggy with low pinion 60s and too big of tires. He bought it with 7.17s, broke them, went to 5.38 or 5.13s, broke those, went to 4.56 and broke those too. Haven't talked to him since. But my conclusion was that if you have an issue breaking gears, different ratios are not really a solution. And your money is much better spent on a bigger diff.

Edit: this may also apply differently to different axles. I've heard internet jabber that lower ratio 9" gears are stronger than higher ratio. :confused:
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I had a buddy go from busting 5.29’s back to 4.56’s and said it was better. But he also then went from toy turd axles to a GM D60/14B because of busted 4.56’s in the end so YMMV.

I went from breaking 5.38 D60’s (3 sets of busted D60 5.38’s personally) to the MegaHi stuff and not breaking anything so MMMV. Also waiting for Tech Tim to do his failure analysis on a D60 ARB for us.
 
Obviously there has to be some strength difference. I just believe it's over hyped. Even the famous Zuk claimed 5.71s were not weaker than 5.29s if set up correctly.
 
JR4X said:
I had a buddy go from busting 5.29’s back to 4.56’s and said it was better. But he also then went from toy turd axles to a GM D60/14B because of busted 4.56’s in the end so YMMV.

I went from breaking 5.38 D60’s (3 sets of busted D60 5.38’s personally) to the MegaHi stuff and not breaking anything so MMMV.
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IMO Dana 60s are the most overrated axle out there. Hi-pin in the front.... yeah OK, you can make them live, depending on your rig, setup, driving style etc. Any other combination/application and you are in a WHEN not IF scenario.

It's why Carl came up with the Jana70.

From Jantz's website:
Benefits:
Dana rates the 60 @ 6000 Ft-lbs maximum momentary output torque. 35 spl HD.

Dana rates the 70 @ 8000 Ft-lbs maximum momentary output torque. Non HD.

That's a 2000 ft-lb increase in capacity.

Also, if you have alloy axles, then your current weak link is the most difficult and expensive part to repair ie: the ring & pinion.
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There's the issue right there.... Aftermarket axle shafts are stronger than the D60 ring and pinion.

Not to mention that a large majority of the axle shafts out there are not built correctly. Transferring more shock load into the ring and pinion.


JR4X said:
Also waiting for Tech Tim to do his failure analysis on a D60 ARB for us.
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Sorry I've been dragging my feet on getting pics. It's been sitting next to the workbench since it arrived. I was working out there yesterday, helping a buddy on a project and showed him the carnage. It's pretty impressive how the starting crack spirals out and around the locker.
 
YotaAtieToo said:
Obviously there has to be some strength difference. I just believe it's over hyped. Even the famous Zuk claimed 5.71s were not weaker than 5.29s if set up correctly.
Click to expand...

Set-up is everything.

I don't think I've ever ran the Toy 5.71s, but have ran multiple sets of 5.29s and set-up up dozens of 5.29s for others and have had very few issues.

That said, there is a point where the Toyota diff is too small and it's time to go to something bigger.

When playing with axles you gotta remember the three strikes rule: Tire size, power/torque and vehicle weight.

You can often live with breaking two of those rules, but break all three and you're likely to be breaking azxle parts. A Toyota wheeler is a great example 35s and a 22RE and you are pretty golden. Step up to 37s/38s (two strikes - weight and tire size) and you can make stuff live by being careful. But as soon as you swap in an engine with more power (third strike)...BOOM.

Also, don't forget the loose nut behind the wheel, that changes all equations 🤣.
 
Tech Tim said:
IMO Dana 60s are the most overrated axle out there.
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I get what you’re saying.

But there are many people out there have great success with D60s and India 4340 shafts. Or even with less of an axle. Like the almighty D30.

A Jeep 4.0 at its peak torque feeding 235 ft-lb through AX-15 in first gear, NP231 in 4x4 low, and 5.38 ring & pinion is 13,171 ft-lb at differential’s carrier. More than a D80 is rated for. But this proved to not be an issue as such perfect (or the worst) scenario is difficult to achieve in real world.

Axle shafts shouldn’t be stronger than ring & pinion is debatable.

Axle shafts being stronger than ring & pinion doesn’t mean a bad thing. Especially when running a locker or spool as one side may take all of torque.

Stronger = longer (or infinite) service life before a fatigue failure will occur.

IMG_2372.jpeg


Good failure analysis manuals.



I think it’s funny on how a lot of shock loading failure analysis in manuals says are from loose nut behind the wheel lol
 
Tech Tim said:
Set-up is everything.

I don't think I've ever ran the Toy 5.71s, but have ran multiple sets of 5.29s and set-up up dozens of 5.29s for others and have had very few issues.

That said, there is a point where the Toyota diff is too small and it's time to go to something bigger.

When playing with axles you gotta remember the three strikes rule: Tire size, power/torque and vehicle weight.

You can often live with breaking two of those rules, but break all three and you're likely to be breaking azxle parts. A Toyota wheeler is a great example 35s and a 22RE and you are pretty golden. Step up to 37s/38s (two strikes - weight and tire size) and you can make stuff live by being careful. But as soon as you swap in an engine with more power (third strike)...BOOM.

Also, don't forget the loose nut behind the wheel, that changes all equations 🤣.
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Agree with all points. Every thing has its place. For west coast trail rig style wheeling where you drive to the trail. A Toyota on 35-37s will do most of the same obstacles as a Toyota on 1 tons and 40s, but is 100 times nicer to drive to the trail.

The rock yota 83 guy admittedly drove like a complete retard. Broke 10 or so chromo birfs, hub parts, ect and never hurt the hp 5.29 arb diff.

Rear diffs seem to live a harder life, especially in a family rig loaded for a 3 day trip.
 
Tech Tim said:
IMO Dana 60s are the most overrated axle out there. Hi-pin in the front.... yeah OK, you can make them live, depending on your rig, setup, driving style etc. Any other combination/application and you are in a WHEN not IF scenario.

It's why Carl came up with the Jana70.

From Jantz's website:


There's the issue right there.... Aftermarket axle shafts are stronger than the D60 ring and pinion.

Not to mention that a large majority of the axle shafts out there are not built correctly. Transferring more shock load into the ring and pinion.




Sorry I've been dragging my feet on getting pics. It's been sitting next to the workbench since it arrived. I was working out there yesterday, helping a buddy on a project and showed him the carnage. It's pretty impressive how the starting crack spirals out and around the locker.
Click to expand...
I’d like some tech on the axle shaft shock load info.
TrailTamer said:
I get what you’re saying.

But there are many people out there have great success with D60s and India 4340 shafts. Or even with less of an axle. Like the almighty D30.

A Jeep 4.0 at its peak torque feeding 235 ft-lb through AX-15 in first gear, NP231 in 4x4 low, and 5.38 ring & pinion is 13,171 ft-lb at differential’s carrier. More than a D80 is rated for. But this proved to not be an issue as such perfect (or the worst) scenario is difficult to achieve in real world.

Axle shafts shouldn’t be stronger than ring & pinion is debatable.

Axle shafts being stronger than ring & pinion doesn’t mean a bad thing. Especially when running a locker or spool as one side may take all of torque.

Stronger = longer (or infinite) service life before a fatigue failure will occur.

IMG_2372.jpeg


Good failure analysis manuals.



I think it’s funny on how a lot of shock loading failure analysis in manuals says are from loose nut behind the wheel lol
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Can’t use 5.38 as a torque multiplier because the diff is taking the torque value before 5.38 gets multipled. The axle shaft can see 5.38 multiplier.

Also, split it in half because half the power goes to the front, half to the rear.

Unless someone smarter then me says I’m looking at this wrong
 
06h3 said:
I’d like some tech on the axle shaft shock load info.

Can’t use 5.38 as a torque multiplier because the diff is taking the torque value before 5.38 gets multipled. The axle shaft can see 5.38 multiplier.

Also, split it in half because half the power goes to the front, half to the rear.

Unless someone smarter then me says I’m looking at this wrong
Click to expand...
The carrier still sees the 5.38 multiplier. But I think axle assemblies are rated for input torque on the pinion.

I wouldn't split the power, a bit of a slope and some acceleration makes it easy to have 0 load on the front axle.
 
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