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12 bolt Vs. 9"

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Old 06-22-2007, 06:13 PM
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Default 12 bolt Vs. 9"

are there any disadvantages to getting a 9" over a 12 bolt? because i cant seem to find very many at all.
Old 06-22-2007, 06:39 PM
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nope, not really. about the only thing i've heard people talk about is that you will lose ABS but they actually make kits so you can keep it. i see no benefit of the 12 bolt.
Old 06-22-2007, 06:48 PM
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9 inch weighs more and takes more power to run it versus a 12 bolt. It really depends on what your power goals are.
Old 06-22-2007, 07:00 PM
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12 bolts have held at the 900whp levels. with a good optioned and assembled 12 bolt your transmission will go out befor a 12 bolt will.

with the 9 inch you loose abs and cant take the cover off and have a peek at the gears as easy among a few other things.
Old 06-22-2007, 07:16 PM
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Originally Posted by LS1>girlfriend
12 bolts have held at the 900whp levels. with a good optioned and assembled 12 bolt your transmission will go out befor a 12 bolt will.

with the 9 inch you loose abs and cant take the cover off and have a peek at the gears as easy among a few other things.


That's why my choice is the 12bolt. I see no real reason to go to a 9" unless you are pushing serious HP or it sees ALOT of track time.

plus i'm a lil brand loyal and chevy never made a 9"
Old 06-22-2007, 08:27 PM
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Originally Posted by djsanchez2
plus i'm a lil brand loyal and chevy never made a 9"
I'm Chevy all the way too... but chevy isn't making the 12 bolt or 9" for our cars. They are either Strange or Moser.

But anyway, I went 9" because it is stronger and manual launches are violent. They are stronger and you can keep your ABS if you are 4-channel. They are also easier to change gear ratio. It weighs a small amount more than a 12 bolt and uses a small amount more hp. We aren't talking a lot 25# and maybe 5HP.

Brian
Old 06-22-2007, 09:50 PM
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That is true that the 12 bolt casting is completely aftermarket and only the cover resembles what we used to know. However, there are still applications where the 9'' may be overkill.

What about axle tubes? The 9'' tubes are larger so your perch will be farther off right?
Does anyone know if you have issues with clearances after the 9'' install? Would be interesting to know how it effects your swaybar, shocks, exhaust, ect.
Old 06-22-2007, 11:11 PM
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My car does sit higher and the axle is rearward with the 9". I think my car gained about 1" and I think the axle is rearward about .75". Also there is no provision for brake lines or park brake cable on the 9" so you need to tie wrap them or come up with something fancy.

I have no clearance issues, everything just bolts up. I changed to shorter drop links on my stab bar, but they broke anyway removing them. I also put a 1/4" spacer to lower my stab bar cause it hit the torque arm mount.

Brian
Old 06-22-2007, 11:31 PM
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I would rather go with a S60. About the same price, Bullet-proof, 3 or 4 channel abs, doesnt eat up a much power as a 9" and only weighs a few pounds more.
Old 06-23-2007, 01:55 AM
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i didn't know anyone made an s60 for our cars. why are they not as popular?
Old 06-23-2007, 04:41 AM
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Originally Posted by 2002_Z28_Six_Speed
That is true that the 12 bolt casting is completely aftermarket and only the cover resembles what we used to know. However, there are still applications where the 9'' may be overkill.

What about axle tubes? The 9'' tubes are larger so your perch will be farther off right?
Does anyone know if you have issues with clearances after the 9'' install? Would be interesting to know how it effects your swaybar, shocks, exhaust, ect.
Both Moser 12 bolt and 9 inch rears use 3.00" diameter axle tubes. Bob
Old 06-23-2007, 08:17 AM
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Originally Posted by 00PewterSS
Also there is no provision for brake lines or park brake cable on the 9" Brian
Do you mean the little tabs which hold the lines from vibrating all over the place?
Old 06-23-2007, 10:33 AM
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Originally Posted by Duffster
Do you mean the little tabs which hold the lines from vibrating all over the place?
Yes. It doesn't have anything for the lines to hold them. As I understand the 12 bolt does... at least some do.

Brian
Old 06-23-2007, 09:37 PM
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Thanks for the info. Wish I knew that about the axle tubes before as I still don't have adjustable shocks on the back and I was concerned about that. I measured my 12 bolt tonight and found that it had 3'' axle tubes. My 12 bolt didn't have the tabs for the brake lines but I ordered it to be built ASAP so maybe they skipped them.

Last edited by 2002_Z28_Six_Speed; 06-26-2007 at 09:20 AM.
Old 06-23-2007, 10:01 PM
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i didn't know anyone made an s60 for our cars. why are they not as popular?
Strange just came out w/ the bolt in S60 for our cars not too long ago. Going by the specs it seems pretty strong....comes standard w/ 35 spline axles and a 9.75" ring gear. Not bad eh?
Old 06-24-2007, 05:21 AM
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I just routed and installed brake lines on my Strange 12 bolt tonite.
The brake line tabs were on mine.

I think up to 600 horse a 12 bolt is fine.
I originally was going to order an S60 but I could not pass up the deal on this 12 bolt.
Old 06-24-2007, 09:44 PM
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the 9" weighs more, robs more horsepower. and you cant use ABS only on the 9", unless there is a kit out there.
Old 06-24-2007, 09:46 PM
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and personally I dont like the way a 9" looks, I dont like the gear ratios offered in the 9" either. However a 9" is a better rear, especially for the manual cars. and you can change the gears for a weekend drag race and then back to streetable gears for the DD ( much easier than doing it on the 12 bolt) and generally the 9" is a more stout rearend.
Old 06-24-2007, 09:57 PM
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Originally Posted by LSGunZ28
I dont like the gear ratios offered in the 9" either.
What, 3.70 or 3.75 instead of 3.73? Some people make 3.73's also. Any ratio that is available for a 12 bolt or 10 bolt is available for a 9". Might be a 4.10 instead of a 4.11, or a 3.89 instead of a 3.90, etc. The only one that is missing is the 3.42, but they have a 3.50 which is damn close. Plus they have all the in between ratios.
Old 06-24-2007, 10:38 PM
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Originally Posted by mzoomora
What, 3.70 or 3.75 instead of 3.73? Some people make 3.73's also. Any ratio that is available for a 12 bolt or 10 bolt is available for a 9". Might be a 4.10 instead of a 4.11, or a 3.89 instead of a 3.90, etc. The only one that is missing is the 3.42, but they have a 3.50 which is damn close. Plus they have all the in between ratios.

Well Id personally stick with 3.50 or 3.55 for street and use 4.56 for drag racing... I guess 3.89 is ideal for both a DD and racer if you dont wanna sway out the ring and pinion..

I didnt like 3.70 because I suspect its semi nonhunting.



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