Swaybars...

E28 technical advice asked and given! Troubleshooting, modifications and more.
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Adam
Posts: 7
Joined: Feb 12, 2006 12:00 PM

Post by Adam »

Anyone know where to find a set of M5 sized swaybars? All the aftermarket sets I've found are smaller (22f/16r, compared to the M5's 25f/19r.) The car I'm planning on purchasing already has Bilsteins and H+R Sport springs (the latter I plan on removing and finding something stiffer and not quite as low.) Basically, I would like the car to handle more like an M5 than a 535.
fastpat
Posts: 1036
Joined: Feb 12, 2006 12:00 PM
Location: Travelers Rest, South Carolina

Post by fastpat »

Adam wrote:Anyone know where to find a set of M5 sized swaybars? All the aftermarket sets I've found are smaller (22f/16r, compared to the M5's 25f/19r.) The car I'm planning on purchasing already has Bilsteins and H+R Sport springs (the latter I plan on removing and finding something stiffer and not quite as low.) Basically, I would like the car to handle more like an M5 than a 535.
Take a look at JayBort's writeup of the M5 bar installation for a detailed installation of the M5 anti-roll bars including part numbers and so forth. The URL is a pdf file.
Lee in LA
Posts: 119
Joined: Feb 12, 2006 12:00 PM
Location: Winston Salem, NC

Post by Lee in LA »

Jim at da shop sells some 22/16 or 25/19 adjustable ST swaybars. I just put the 25/19s on mine not too long ago, and even on the soft settings the difference is nothing short of amazing. The car handles much better now!! Even with the stock springs!

I would think that H&R springs would be significantly stiffer than stock M5 springs. I was under the impression that the spring rates for the 535 and the M5 were actually the same even though the p/n's are different. I think the main difference was the swaybars and the shocks. Skim through this page:http://member.rivernet.com.au/btaylor/B ... artNo.html

If I'm right, you'd actually have to get stock 535 springs.

If you just keep the H&Rs, and put on the beefier swaybars, you'll get better handling than an M5, I suppose.

HTH,


[Edit by Lee in LA on [TIME]1107069354[/TIME]]
Aaron from Aus
Posts: 559
Joined: Feb 12, 2006 12:00 PM
Location: Australia
Contact:

Post by Aaron from Aus »

WHITE-LINE Swaybars

They will even sell you custom 30mm if you ask..not in there catalogue though.).

From there catalogue
Fronts are:
R / 24 / C / BMW E28 5 SERIES (27mm width)
Code: #BBF34X
Price: AU$207.27 (Australian Dollars)

the Rears are:
R / 16 / C / BMW E28 (16mm width)
Code: #BBR34
Price: AU$207.27 (Australian Dollars)

Not sure, but i dont think they make any larger for the rear, so it could unbalance the car..but there products are good...and i think it would only be a benifit to the car. (i intend on buying a set down the track some time.

Link: http://www.whiteline.com.au/ Click on Webstore and do a search...or download the catalogue.
bobs
Posts: 62
Joined: Feb 12, 2006 12:00 PM
Location: Saratoga California USA

Post by bobs »

Read the Short Spring and Sway Guide at http://m535i.org/officers/ra/articles.html#rear to learn about the rates of different springs, also the thicknesses of various sways.

In setting up a car, first you install springs as stiff as you need (or you can stand) for your application, then you use dampers (shocks and struts) appropriate to control the spring rates, then you use the sways to provide any necessary spring rate you couldn't achieve with springs. Remember you're not just trying to control body roll, you're adjusting handling balance (understeer/oversteer) in corner entry, mid-corner, and exit.

We have Eibach springs, Bilstein Sport dampers, and Suspension Techniques 25.4/19mm adjustable sways. It's nicely balanced and the roll is minimized.
fastpat
Posts: 1036
Joined: Feb 12, 2006 12:00 PM
Location: Travelers Rest, South Carolina

Post by fastpat »

bobs wrote:Read the Short Spring and Sway Guide at http://m535i.org/officers/ra/articles.html#rear to learn about the rates of different springs, also the thicknesses of various sways.

In setting up a car, first you install springs as stiff as you need (or you can stand) for your application, then you use dampers (shocks and struts) appropriate to control the spring rates, then you use the sways to provide any necessary spring rate you couldn't achieve with springs. Remember you're not just trying to control body roll, you're adjusting handling balance (understeer/oversteer) in corner entry, mid-corner, and exit.

We have Eibach springs, Bilstein Sport dampers, and Suspension Techniques 25.4/19mm adjustable sways. It's nicely balanced and the roll is minimized.
The sways change the transition of the car from turning in one direction into another if the turns are close as well, don't they Bob?

So, if you run the thicker M5 bars, the car will make cornering changes less demanding on the rest of the suspension. In theory.
louielouie
Posts: 480
Joined: Feb 12, 2006 12:00 PM
Location: Bothell, Wa

Post by louielouie »

Before you put a bigger sway bar (at least in the rear), strengthen the brackets to the frame. Each bracket is only held on by 4 spot welds - with a MIG welder, lay a bead around the outside edges of the brackets after cleaning down to the metal. Or follow Shawn D's advise after the bracket tears off. I was lucky that only the welds broke. BTW, my 25/19 ST bars (with staggered tire sizes) are set stiff in the rear and 'medium' in the front for very neutral handling characteristics.
Image
Adam
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Joined: Feb 12, 2006 12:00 PM

Post by Adam »

Wow, thanks for the quick replies! It sounds like the Suspension Techniques bars are what I'm looking for (unless I just happen to stumble across an M5 being parted :p ).. Now I just have to find someone who sells the correct set.
The H+R springs that are on the car will probably be complimented nicely by the swaybars, however, I feel they lower the car too much..especially with the 3 inch exhaust thats on it. I'd like to find something in a similar spring rate, but that doesn't drop the car on its belly; although theres no real hurry on that.
I'll definitely have the brackets strengthened before I add any swaysbars.. I've seen a few cars that have had the brackets torn or ripped clean off..not fun!
fastpat
Posts: 1036
Joined: Feb 12, 2006 12:00 PM
Location: Travelers Rest, South Carolina

Post by fastpat »

Adam wrote:Wow, thanks for the quick replies! It sounds like the Suspenion Techniques bars are what I'm looking for (unless I just happen to stumble across an M5 being parted :p ).. Now I just have to find someone who sells the correct set.
The H+R springs that are on the car will probably be complimented nicely by the swaybars, however, I feel they lower the car too much..especially with the 3 inch exhaust thats on it. I'd like to find something in a similar spring rate, but that doesn't drop the car on its belly; although theres no real hurry on that.
I'll definitely have the brackets strengthened before I add any swaysbars.. I've seen a few cars that have had the brackets torn or ripped clean off..not fun!
One thing that you should consider is installing the M5 front bar brackets and using the rubber bushings for the 25mm bar with the ST 25mm adjustable bar. I think you get a thin polyurethane bushing to work with the stock bar mounts, and that's really sub-par. The M5 parts are very beefy and even more important, they're quiet.

Pat
Lee in LA
Posts: 119
Joined: Feb 12, 2006 12:00 PM
Location: Winston Salem, NC

Post by Lee in LA »

Adam wrote:Now I just have to find someone who sells the correct set.


"Jim@da shop" sells the 25/19 ST(suspension Techniques) swaybars. I don't remeber his #, and I don't think he's registered on here yet, but you can find him on the "old" forum.

HTH


[Edit by Lee in LA on [TIME]1107110698[/TIME]]
bobs
Posts: 62
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Location: Saratoga California USA

Post by bobs »

bobs wrote:Remember you're not just trying to control body roll, you're adjusting handling balance (understeer/oversteer) in corner entry, mid-corner, and exit.
fastpat wrote:The sways change the transition of the car from turning in one direction into another if the turns are close as well, don't they Bob?
You're in a turn until your weight is back to its normal distribution, and there's no more turning moment about the vertical axis thru the CG. If two turns are close enough together enough that you're constantly in motion from one to the next, with no pause to go straight in between, they're "connected". Springs and sways affect how much weight shifts, and dampers affect how quickly it shifts.
So, if you run the thicker M5 bars, the car will make cornering changes less demanding on the rest of the suspension. In theory.
I wouldn't say "less demanding", I would say sways supplement the lacking spring rate. With soft springs and stiff sways, you'll be more prone to tear the brackets off.
fastpat
Posts: 1036
Joined: Feb 12, 2006 12:00 PM
Location: Travelers Rest, South Carolina

Post by fastpat »

bobs wrote:Remember you're not just trying to control body roll, you're adjusting handling balance (understeer/oversteer) in corner entry, mid-corner, and exit.
fastpat wrote:The sways change the transition of the car from turning in one direction into another if the turns are close as well, don't they Bob?
Originally posted by bobs"]You're in a turn until your weight is back to its normal distribution, and there's no more turning moment about the vertical axis thru the CG. If two turns are close enough together enough that you're constantly in motion from one to the next, with no pause to go straight in between, they're "connected". Springs and sways affect how much weight shifts, and dampers affect how quickly it shifts.


Makes me think of the corkscrew at Laguna Seca, that turn will try out your anti-roll bars for sure

fastpat wrote:So, if you run the thicker M5 bars, the car will make cornering changes less demanding on the rest of the suspension. In theory.

Originally posted by bobs"]I wouldn't say "less demanding", I would say sways supplement the lacking spring rate.


Supplement spring rate in a turn only, naturally, that keeps us from having springs like a buckboard and shocks with too much dampening.

Originally posted by bobs"]With soft springs and stiff sways, you'll be more prone to tear the brackets off.


Yes, I can see how that would work, thanks for the suspension dynamics info.
Layton
Posts: 562
Joined: Feb 12, 2006 12:00 PM

Post by Layton »

Adam wrote:Anyone know where to find a set of M5 sized swaybars? All the aftermarket sets I've found are smaller (22f/16r, compared to the M5's 25f/19r.) The car I'm planning on purchasing already has Bilsteins and H+R Sport springs (the latter I plan on removing and finding something stiffer and not quite as low.) Basically, I would like the car to handle more like an M5 than a 535.
While you're going through the motions of the sway bar upgrade, take a look at
Shawn D.'s write-up on bracket reinforcement: http://www.mindspring.com/~scrappycrow/ ... acket.html
fastpat
Posts: 1036
Joined: Feb 12, 2006 12:00 PM
Location: Travelers Rest, South Carolina

Post by fastpat »

Adam wrote:Anyone know where to find a set of M5 sized swaybars? All the aftermarket sets I've found are smaller (22f/16r, compared to the M5's 25f/19r.) The car I'm planning on purchasing already has Bilsteins and H+R Sport springs (the latter I plan on removing and finding something stiffer and not quite as low.) Basically, I would like the car to handle more like an M5 than a 535.
Layton wrote:While you're going through the motions of the sway bar upgrade, take a look at
Shawn D.'s write-up on bracket reinforcement: http://www.mindspring.com/~scrappycrow/ ... acket.html
I talked to Shawn about that, in anticipation of doing the same BEFORE the mount breaks. He thought that if he'd welded his mounts, as recommended above, that he'd not have broken anything. The old "ounce of prevention being worth a pound of cure" cliche'.

Pat
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