9" stronger than D70?

[jode]

Check this out:

http://www.truehi9.com/index.html

According to them, a 9" with 35 splines would be "far" stronger then a D70...

Rebuttal?

[jeepsr4ever]

ah......... These guys are from my neck of the woods. I would like to know what part is stronger than a dana 70

[KaiserMan]

What the heck are they smoking?

[jode]

Originally posted by jeepsr4ever:
I would like to know what part is stronger than a dana 70

Read the link in the link - it explains what parts they say are stronger:

http://performanceunlimited.com/illustrations/gears.html

[ September 28, 2005, 04:44 PM: Message edited by: jode ]

[jeepsr4ever]

Doesnt mean much when the shaft area of the pinion is rated only slightly higher in load for the load of the tooth contact. Sure you can make a huge pinion and wide ring gear and then your snapping pinions so to make up for that you add a boss at the end of the pinion that rides on a bearing and this keeps the gears from shearing off and gives the pinion stem a slightly higher load rating........BUT Ford never used any 9's in larger trucks and for good reasons.

[jode]

Originally posted by jeepsr4ever:
.......BUT Ford never used any 9's in larger trucks and for good reasons.

That's cause Ford didn't have the "truhi9" 3rd member

Just playing devil's advocate here - would like to see some good discussion positively refuting the claim.

[jeepsr4ever]

I understand that....yeah the true high 9 is the BEST high pinion 3rd member ever made.

[Stuka]

The ring and pinion arent everything. The D70 has much larger tubes that are thicker, the shafts are bigger, and as I recall, a high pinion differential used in back is weaker, as it drives on the coast side of the R&P, rather than the drive side. Unless they have reverse cut the gears to make up for this. This is why people never run a high pinion in back. I can see why the did it, the 9" has a VERY low pinion in standard configuation and it gets caught by everything.

[ September 28, 2005, 07:39 PM: Message edited by: Stuka ]

[zmjeeps]

If you guys really want a two page chapter and verse on why that whole page is BS, I could give it to you (I work at Dana designing axles). Long story short, he's comparing different ratio gears. Ring gears get thicker/thinner when the ratio changes. Likewise the head of the pinion gets larger and smaller. And the tooth contact ratio? All manufacturers try to get as many teeth in contact as possible, espically when the pinion gets small. That article takes little pieces of knowledge from the industry and bends it to say the 9" is better than everything else, and its just not true.

[KaiserMan]

That page is definitely a bunch of BS. 9" inch rears are decent little axles, but there no way they are as strong as 70's, even modified.

[ September 28, 2005, 07:18 PM: Message edited by: KaiserMan ]

[blt2krl]

Originally posted by zmjeeps:
If you guys really want a two page chapter and verse on why that whole page is BS, I could give it to you (I work at Dana designing axles). Long story short, he's comparing different ratio gears. Ring gears get thicker/thinner when the ratio changes. Likewise the head of the pinion gets larger and smaller. And the tooth contact ratio? All manufacturers try to get as many teeth in contact as possible, espically when the pinion gets small. That article takes little pieces of knowledge from the industry and bends it to say the 9" is better than everything else, and its just not true.

I was thinking the same thing.

[Stuka]

That had crossed my mind, but I thought who would actually bend words that way? But looking again, it doesnt look that way. One bad thing about the net, ANYBODY can post stuff up, and people believe it. whether it is ring or wrong.

[gsmikie]

go to the hemi cuda board im pretty sure those guys would much rather run a 9er then a 60/70 but then i never had snap-on tell me to go buy mac tools cause they were better either seems what im selling is always better than what im not selling

[Stuka]

A 9 inch is much prefered for a muscle car for quite a few reasons. A: Its a semi-full float, so they can use normal wheels with a normal lug patern. B: They dont have to run big tires in back to clear the big pumpkin of the 60/70. C: The 9" weighs WAY less. D: Its easy to swap in and out gears for different runs.

The 9" is the perfect axle for most muscle cars. Its NOT the perfect choice for offroad. A full float axle will almost always be stronger than a similar sized semi-full float.

[gsmikie]

if it would only hold up to the 426