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Discussion Starter #1
okay i've heard that d44 gears get weaker the deeper you go. i.e., running a 4.88 or 5.38 is not good for a d44. how true is this? i'm probly gonna drop 4.10s or 4.56s in my front 44 eventually, with 35" tires (q78x15). probly no locker or spool unless i lunchbox it.

so does the smaller pinion size have a huge effect on gear strength? does this affect other axles as well like the AMC20 or D60? i read in that ford 9" article that the 9" actually gets stronger the deeper you go.
 

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On a D30, yes I wouldn't go lower (higher numberically) than 4.56. Somewhere I read that places like 4WPW won't do 4.88s in the 30 anymore. In a 44 you are dealing with larger ring gear (in every dimension) so this isn't so much of a problem. In a 60 or 9", you can go into the 6's, evens 7s with the 9".

Then there was the guy from Sacto with the TJ with D30 running 44" tires. Weirdest thing I ever saw coming down the Barrett trail....
 

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All ring and pinions get weaker the deeper you go. The ring gear for a specfic model of axle is a specific size. The only way to change the ratio is to change the size of the pinion gear. For deep ratios, the pinion gear must get smaller. So for a 4:1 ratio, the pinion gear is 1/4 times the size of the ring gear. If the ring gear is small, like in a D30, the pinion will be tiny. The only way around it is to get another axle with a bigger ring gear. I don't see how those guys are claiming the 9 inch gets around that.
 

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Originally posted by Grandpa_Jeep:
<STRONG>I don't see how those guys are claiming the 9 inch gets around that.</STRONG>
me neither really. i believe they said it had something to do with the contact surface increasing on the pinion, thus distributing the load more evenly.
 

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Originally posted by SeanP:
<STRONG>Then there was the guy from Sacto with the TJ with D30 running 44" tires. Weirdest thing I ever saw coming down the Barrett trail....</STRONG>
I saw that guy before. I wish I owned the parts house that he buy replacement parts from. That guy must hammer his shiat, he is running the 35c in the rear. Man that is some clearance though.
 

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You could always have the R&P cryogenicly frozen, and then shot-peened. It will give you a bit more strength and durability.

Steve
 

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Well, I re-read that article, and I think I see what's happening. Here's the picture from that site:


From the looks of that picture, the Ford 9" changes ratio more by gear pitch than by pinion size. As you can see, the pinons are about the same size, but the 5.13 pinion has fewer teeth on it. The only way I see that working is since the pinion is so low, it's almost a worm gear. Because the pinion gear is so low on the ring gear, it's actually pushing the ring gear more forwards and backwards rather than up and down. The ratio is changed by changing the pitch, like going from a fine thread screw to a coarse thread screw. Other axle models have the pinion higher and they push more up and down rather than back and forth. Changing the pitch on them doesn't do as much so they must make the pinion gear smaller, and make the ring gear thicker to get a lower ratio. Makes sense to me, what do you think?
 

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Originally posted by Grandpa_Jeep:
<STRONG> Makes sense to me, what do you think?</STRONG>
Meks sance tome toooo... <IMG SRC="smilies/beer.gif" border="0"> <IMG SRC="smilies/beer.gif" border="0"> <IMG SRC="smilies/beer.gif" border="0"> <IMG SRC="smilies/biggrin.gif" border="0">
 
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