rear ends

**Ls1m6Nichols** · 01-30-2011, 05:44 PM

what is the difference between the 9 inch, 12bolt, and the S60. how much they weight, how strong, and noise difference

**pajeff02** · 01-30-2011, 06:01 PM

Strength: S60 > 9" > 12 bolt

Weight: S60 > 9" > 12 bolt

Efficiency: 12 bolt > S60 > 9"

May have the 9" and S60 reversed in the last one, but you get the idea.

**Demon_Z28** · 01-30-2011, 07:36 PM

I think the S60 has the most loss in efficiency but pretty dead on.

**pajeff02** · 01-31-2011, 03:31 AM

Originally Posted by Demon_Z28

I think the S60 has the most loss in efficiency but pretty dead on.

You may be right. The efficiency equation has to do with the pinion offset from the ring gear. Car Craft had a great article on this around 2 years ago. If I happen to find it, I'll post up the link as it is good reading.

**ls1camino** · 01-31-2011, 07:53 AM

Might want to throw cost into that little chart...

9" > 12-bolt > S60

aka: the 9" is the cheapest ad the S60 is the most expensive.

**0rion** · 01-31-2011, 07:57 AM

also the 12 bolt is a direct bolt in where you might have to do a little banging/fabbing here and there on the others.

**bberretta** · 01-31-2011, 08:41 PM

There are a couple of companies that make direct bolt-in S60s and 9". My MidWest Chassis 9" went right in with no real modifications. I upgraded the driveshaft so I wouldn't have to use an adapter u-joint, but aside from that I could have used the stock control arms, PHB, and everything else. Also, the cost really depends on how you build it. You could build a 12-bolt that is more expensive or a 9" that costs over $4k.

Here's how I look at it- they are all better than the stock one! S60 has the largest ring gear diameter (9.75") whereas the 9" is, well, 9 inches, and the 12-bolt is 8.8 inches. This, along with weight, pinion offset, etc, helps to also explain the efficiency differences.

**KMdef9** · 02-03-2011, 02:28 PM

Originally Posted by pajeff02

Strength: S60 > 9" > 12 bolt

Weight: S60 > 9" > 12 bolt

Efficiency: 12 bolt > S60 > 9"

May have the 9" and S60 reversed in the last one, but you get the idea.

Do you lose ABS with all of these?

**pajeff02** · 02-03-2011, 03:24 PM

Originally Posted by KMdef9

Do you lose ABS with all of these?

As far as I know, you can option all of them for either ABS or ABS/TCS.

**bberretta** · 02-03-2011, 05:50 PM

Originally Posted by KMdef9

Do you lose ABS with all of these?

Depending on who makes the rear, you can order it with a 3-chan (just ABS) or 4-ch (ABS and TCS) modifications. My MidWest Chassis 9" could be ordred with either setup.

**pajeff02** · 02-03-2011, 05:55 PM

Just for giggles... here are some pics. First one shows the stock and aftermarket Moser 33 spline axle for my 12 bolt. Second is how I pressed off the reluctor rings to transfer them to the Moser axles.

**KMdef9** · 02-04-2011, 04:48 AM

Originally Posted by pajeff02

Just for giggles... here are some pics. First one shows the stock and aftermarket Moser 33 spline axle for my 12 bolt. Second is how I pressed off the reluctor rings to transfer them to the Moser axles.

Reluctor rings are for TC, correct? And the spline Behind the ring gear is the ABS?

**5150** · 02-04-2011, 05:05 AM

I've got the S60 and their chrome moly drive shaft. At the time, which was 3-4 years ago, the S60 was cheaper than their 12 bolt. That was the deciding factor for me. The only complaint I have about it is a little howling from it around 1,800 rpm's.

**pajeff02** · 02-04-2011, 06:35 AM

Originally Posted by KMdef9

Reluctor rings are for TC, correct? And the spline Behind the ring gear is the ABS?

On ABS/TCS cars there is no reluctor on the ring gear. It utilizes the same sensors for both at the ends of the axles. ABS cars only have a reluctor on the ring gear.

**KMdef9** · 02-04-2011, 07:29 AM

Originally Posted by pajeff02

ABS cars only have a reluctor on the ring gear.

That's me! Thanks!

**Aetos** · 02-04-2011, 03:45 PM

Originally Posted by Demon_Z28

I think the S60 has the most loss in efficiency but pretty dead on.

Actually, I'm pretty sure the s60 is more efficient than the 9" which somewhat makes up for its weight. Something about the s60 pinion hitting the gear in a better way or something.

**pajeff02** · 02-04-2011, 03:56 PM

Here is the link to the Car Craft article: http://www.carcraft.com/techarticles...wap/index.html

**Cutlass** · 02-04-2011, 05:53 PM

Originally Posted by Aetos

Actually, I'm pretty sure the s60 is more efficient than the 9" which somewhat makes up for its weight. Something about the s60 pinion hitting the gear in a better way or something.

Yes, and the article Jeff posted points that out. The 9" pinion offset causes more friction and takes a little more power to turn.