Upgrading stock rear sway bar to OEM RS4 bar?

**GeoFX** · 10-04-2008 03:54 PM

Thinking about upgrading my B6 S4 rear sway bar (20mm) to an OEM RS4 rear sway (22mm). Would the extra 2mm thickness make much of a difference or am I just wasting money? Has anyone done this swap? The newer B7 S4s evidently have 22mms sway bars now...same front bar.

Thinking about doing this instead of the H-Sport route due to cost constraints...:(

Thanks!

**S4DTM** · 10-04-2008 04:15 PM

This will definitely make a difference if you are driving hard enough to get a good amount of body roll from the car. The B7 has a smaller rear sway than the RS4 as well (not sure on the exact numbers), but I know it makes a fairly significant difference in body roll.

**covertS4driver** · 10-04-2008 05:05 PM

It makes a noticeable difference...

Especially if you do some hard driving, or a little canyon carving.

**norsecarnut** · 10-05-2008 01:26 AM

Originally Posted by S4DTM

This will definitely make a difference if you are driving hard enough to get a good amount of body roll from the car. The B7 has a smaller rear sway than the RS4 as well (not sure on the exact numbers), but I know it makes a fairly significant difference in body roll.

The 2008 S4 Avant has 22mm rear, 30 mm front.

You might consider going past that to the Hotchkiss bars, 35mm fr/24mm rear

**ginkof** · 10-05-2008 02:47 AM

Yeah definitely go with these... i bought the h-sport sways for the RS4 instead of the S4... with coils and the rear bar in the stiffer position my car almost wants to oversteer! I bought them for $417 shipped from tirerack.... Without a doubt the best mod for the money (even without coils) and i installed them myself with common tools in an hour. Hotchkis is definitely the way to go!

S4 set up is 35mm front 24mm rear. 60% and 70% stiffer respectively over OEM S4

RS4 set up is 35mm front 29mm rear 60% stiffer up front, 235-305% stiffer in the rear over OEM RS4.

I say go for the RS4 set-up... they bolted on perfectly onto my 04 S4 even though you have to dial in an 07 RS4 on the tirerack website. Same price too.

Originally Posted by jwest

The 2008 S4 Avant has 22mm rear, 30 mm front.

You might consider going past that to the Hotchkiss bars, 35mm fr/24mm rear

**EYE4SPEED** · 10-05-2008 06:46 AM

Would Neuspeed also be an option? Anybody have percentages and feedback on those?

**DeatschWerks** · 10-06-2008 07:10 AM

Originally Posted by ginkof

Yeah definitely go with these... i bought the h-sport sways for the RS4 instead of the S4...

Did these bars change ride quality at all? I really don't want to sacrifice ride comfort for daily driving.

**whartung** · 10-06-2008 08:06 AM

no not at all. you don't notice the bar unless you drive it a bit harder than you would daily driving.

**Stevelev** · 10-06-2008 09:03 AM

If you want a real noticeable difference (ie: reduction in understeer) go with the rear h-sport RS4 only. The OEM RS4 isn't that much stiffer and I had a fair amount of understeer in my car with the stock setup (2007 S4's came with the OEM RS4 rear bar). That said, getting a pair of RS4 H-sports will provide better turn in and flatter cornering but the beefier front bar does add back some push (understeer). There was no noticeable difference in the ride of my car when adding the h-sports.

Here's some info I gathered ...

RS4 H-sports
35mmF and 29mm rear
Front 60% stiffer/ Rear +235%, and +305% stiffer than OEM
90% stiffer than S4 H-sport rear

S4 H-Sports
35mm front and 24mm rear
Front 60% stiffer/ Rear +145% & 215% stiffer than pre-2007 OEM (2007+ come with RS4 rear)
30% stiffer than A4 H-sport rear

A4 H-sports
35 mm front and 22 mm rear
Front: +60% stiffer/ Rear: +120% & +150% stiffer than OEM

**kurtdaniel** · 05-28-2009 05:34 AM

you would definitely notice the change..better stay with your oem parts from overnight auto parts..

**sakimano** · 05-28-2009 08:44 AM

Originally Posted by GeoFX

Thinking about upgrading my B6 S4 rear sway bar (20mm) to an OEM RS4 rear sway (22mm). Would the extra 2mm thickness make much of a difference or am I just wasting money? Has anyone done this swap? The newer B7 S4s evidently have 22mms sway bars now...same front bar.

Thinking about doing this instead of the H-Sport route due to cost constraints...:(

Thanks!

I traded S4s for a week with a friend who has a B6

the RS4 sway bar and 2007S4 Torsen T3 vs his 20mm and Torsen T2 really change the feel of the car. I'm not sure how much is the diff, and how much is the sway. I've never heard of anyone actually doing this upgrade though, as they tend to go straight to H-Sport (and then tend to start threads about how it broke a few months later!)

**teknostar** · 05-28-2009 05:45 PM

I am interested in this as well, as i have a 2004 S4 and have a RS4 rear sway bar that i am contemplating putting on. Has anyone done this, and is it ok to replace the rear sway bar and leave the front stock?
What changes to handling can we expect from this mod? Is it a worthwhile upgrade?

**Stevelev** · 05-28-2009 07:42 PM

Originally Posted by teknostar

I am interested in this as well, as i have a 2004 S4 and have a RS4 rear sway bar that i am contemplating putting on. Has anyone done this, and is it ok to replace the rear sway bar and leave the front stock?
What changes to handling can we expect from this mod? Is it a worthwhile upgrade?

The front sway is the same in both the S4 and RS4 so yes, leaving the OEM front bar is fine. You will not notice anything earth shattering with the beefier rear sway but should feel less "push" (understeer) when driving aggressively. If you drive like a granny then no, its really not worth the upgrade; however, it will provide an improvement in handling when driving "enthusiastically".