z28misfit

iTrader: (3)

This question has most likely been asked 100x but yeah well. I can't decide wether to get a Moser 9'' or 12 bolt. I want everything to bolt up to it. I saw the 9'' needs the brake lines run better than the stock ones, that's no big deal. It basically comes down to price for quality. I don't want too regret buying the wrong rear.Thanks in advance!

2000TransAmWS6

iTrader: (12)

to me the cool thing about the 9in is that its very easy to work on, and it is pretty easy to find parts for it... not to mention that it has a reputation for being VERY strong.

i ended up buying a 12bolt, because i wanted to keep things all GM, and although its harder to set up a 12 bolt than 9in i can do it if i can take my time. also, to me the 12 bolt was plenty strong for what i was going to be doing with the car.

z28misfit

iTrader: (3)

I just got off the phone with Moser and they pretty much pointed me in the 12bolt direction. They said the 9'' is stronger with a spool. The biggest posi unit with a 9'' is 31 splines so therefore I may as well go with a 33 splined posi 12 bolt. Plus I may as well keep my abs crap.

00WHITETA

iTrader: (1)

You can keep all your posi and t.c.s's stuff with a 9" I did!! I got the True Tracs in mine 31 spline and it seems to work good.

z28misfit

iTrader: (3)

How did you get it to work?

blue01ta

iTrader: (4)

I don't know where you heard that at but it's wrong. I have a 9". No problems with the brake lines at all. The factory brake lines bolted right up.

2QuickZ's

I went with a 33 spline 12 bolt w/ Tru Trac. I got a great deal from Scott at Driveline Solutions. I didn't get a chance to get the car to the track so we'll see how it holds up to the clutch dumps. I can tell you the car basically drives like stock and other than some very minor whine at around 45 mph at a steady speed the thing is very quiet.

EPP

iTrader: (22)

I personally prefer the Moser 9 inch over the Moser 12 bolt. Moser uses the oem method of bolting the torque arm to the 9 inch rear, but on the 12 bolt Moser uses four short bolts. These four bolts have a tendency to come loose, even with loctite.
I bought the Moser 12 bolt for my own '99 Z28 approx four years ago, the torque arm bolts have come loose many times. The next time I'm going with the nine inch, which is also a stronger rear-end.


Moser Rear End Prices At Exotic Performance Plus
Moser 12 Bolt with Truetrac for F Body, your choice of gear ratio
33 Spline Axles with 10 year warranty
ABS (3 channel) or ABS/TCS (4 channel)
Performance aluminum cover
$2,350.00 plus Freight Collect Shipping

Moser 9 Inch with Truetrac for F Body, your choice of gear ratio
31 Spline Axles
$2,400.00 Shipped by UPS

Moser 9 Inch with Truetrac for F Body, your choice of gear ratio
31 Spline Axles
ABS/TCS (4 channel) 3 channel not offered
$2,500.00 Shipped by UPS

Moser 9 Inch with spool, your choice of gear ratio
35 spline axles
Aluminum center section
$2,250 shipped by UPS

Moser 9 Inch housing and axles with torque arm bracket
Your choice of axle spline
Narrowed housing, no extra charge.
$1,000.00 shipped by UPS

Call us at 260 244-4808. Rear ends are ready to ship two days after order is received. Thanks! Bob

YodiBrodi

which is the lighter option? i know you can get the 9" with an aluminum housing is there any such option with the 12bolt? does anyone know how the aluminum 9" weight compares to the 10bolt weight?

Mean Green z28

iTrader: (17)

I don't think so, the 12 bolt is cast iron only .. unless I'm wrong and haven't seen an aluminun version. I know the 9" is heavier than the 12 bolt nomatter what!

EPP

iTrader: (22)

The Moser 9" aluminum option is only for the spool, it is too thick to use it with the Truetrac.
We weighed a Moser 12 bolt/truetrac and a Moser 9"/spool with the aluminum center, and the 9" was 20lbs lighter. Not a direct comparison, as the spool is lighter than a truetrac.
I don't know what the 10 bolt weighs, but it is too small to be considered as an alternative. Bob

z28misfit

iTrader: (3)

I was also considering Stranges 12 bolt. Never heard too much about them really, seems like everyone goes with the Moser. Not sure what posi units they use. I would like the True Trac when I get a rear.

Brianss1

Not has many out there but I realy like my DTS 12 bolt,with 3" Moser axles,31 spline,3.73 Eaton, and my abs.They are located in Michigan.

Jeremiah

iTrader: (5)

Yea, you lose a lot of weight when going to a spool..

Other than pinion suppt. I dont know of any other features on the 9" that are stronger than the 12 bolt. If you want an OEM style mounting of the torque arm the Strange set up is the choice over Mosier. The 12 bolt also transfers power to the ground more eficiently than the 9" with far less reciprocating weight and an advantage of the pinion location. The pinion gear on the 12 bolt is located 1.5" below the axle center line, a 9" is 2.25" below the axle center line. This gives the 12 bolt an advantage of lower gear lubricant temperature, increased fuel economy and best of all more power to the ground. I hear the nogular iron housing on the 12 bolt is also far stronger than the 9" and needs no additional bracing. If you plan on running a street set up without a full spool I have been told the posi unit for the 12 bolt is also stronger than that that is offered for the 9"?

its scot

iTrader: (1)

I DO NOT HAVE any first hand ex. with it but a guy at moser and at performance rear. told me that sometimes you get a vibration in an f body with a 9in that is very dificult to fix. it has to do with a 1 inch offset that is needed to fit the 9in in the car? so I went with the 12 bolt!

EPP

iTrader: (22)

The nine inch rears are stronger than the 12 bolts. Yes the 12 bolts are a little more efficient, but the nine inch rears are stouter and stronger. You often can take a quiet sounding 12 bolt, dump the clutch at 4000 rpm several times, and pick up whining noises that it didn't have before. That doesn't normally happen with a nine inch.
Ask the guys with 8 and 9 second cars what they use. Bob

getusum

iTrader: (42)

9 inch if you have a m6,.....12 bolt with an a4....I've got the 9 inch, got it from Bob @EPP....excellent guy to work with...very helpful on the descision......I dump it @ 6k yanks them right off the ground.....that's my 2 cents

Jeremiah

iTrader: (5)

That would probably be from the weaker pinion suppt in the 12 bolt?

Im not rying to say the 12 bolt is stronger, just stating a few of the advantages I heard of, I am by no means an expert on the subject.
I know most of the serious racing guys run the 9" due to ease of repair/replacement, they usually have extra center sections allready set up ready to swap into the car.

I would like to hear from some guys that can point out the exact weak points and strong points from each 12 bolt and 9". The 9" is stronger but what makes it stronger? At what point should the extra cost of the 9" be considered over the 12 bolt and why?

N2O-ARMD

iTrader: (1)

The 12 bolt is stronger by design but both are extremely strong in their own right 9" is eaiser to set up and make gear changes to if you have a spare center section I had some trouble with my moser 12 bolt with breaking ring gears but I found that moser had it set up wrong. they did not have enough bearing load on the carrier. the 9" is heavier and the tread about the bolts coming loose I used grade 10 bolts loctite and lock washers and I have never had them come loose. I have a eaton posi with 33 spline, richmond 4:10s and have gone in the 9's without any problems since I rebuilt the rear when I went 9's I had 3:73 motive's. If you go with a 9" call Danny Miller he has one of the baddest housings available. (636-861-3900) I don't know his web site so just give him a call.

EPP

iTrader: (22)

The 9-inch has an internal rear-pinion support that also supports the gear end of the pinion to limit gear deflection under high torque loads. This seems to be the major reason why the 9 inch doesn't start whining after high rpm clutch dumps, when the 12 bolt will pick up noise.

The 9-inch locates its pinion gear lower on the ring gear to improve tooth contact, than the 12 bolt does.

The 9-inch has a 0.125-inch larger ring-gear diameter and internal pinion support than the 12 bolt does. This is not much of a difference, but it is worth noting. Bob