# Front Anti-Sway Bar Change Worth it?



## jvr826 (Apr 22, 2002)

I've swapped out the rear anti-sway bar for the M5 bar and love the results. I'm wondering if anyone has done the rear bar, then decided to do the front. It's a big investment in time and I would like your opinions - is it worth the effort?

tia,


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## marinakorp (Oct 3, 2003)

jvr530i said:


> I've swapped out the rear anti-sway bar for the M5 bar and love the results. I'm wondering if anyone has done the rear bar, then decided to do the front. It's a big investment in time and I would like your opinions - is it worth the effort?
> 
> tia,


personally, I would say No... I like the bias to the rear, and would not want to stiffen up the front, unless I went with a LARGER (than the M5 one) rear

Sure, the suspension will be stiffer all around, but I like the fact that the bias is to the rear, and can come around a bit "better" than the stock setup.

case in point, there are a few racers (and I realize that we are not talking apple and apples here, but the principal is the same) in the saturn world that would put the 17.5 mm rear bar on their SC2 and put the smaller SC1 bar on the front, to get the rear to "step out" a bit, depending on the application... if you increase the diameter of the front.. the handling characteristics go back to the stock type, but with decreased body roll

again, this is just my opinion


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## Steve D (Oct 10, 2002)

It is hard to believe that a small 1mm increase in bar diameter could produce such noticable results but I installed a M5 rear swaybar a few months ago and there was a big improvement in handling. The car is more neutral and controllable. I really recommend it.

I also have the front M5 bar but have not installed it because of the effort required. Now I am thinking of not installing it at all since it might bring back more understeer even though roll will stiffen. Now for new rear tires.

Steve D
'00 540/6sp


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## DZeckhausen (Mar 11, 2003)

Steve D said:


> It is hard to believe that a small 1mm increase in bar diameter could produce such noticable results but I installed a M5 rear swaybar a few months ago and there was a big improvement in handling. The car is more neutral and controllable. I really recommend it.
> 
> I also have the front M5 bar but have not installed it because of the effort required. Now I am thinking of not installing it at all since it might bring back more understeer even though roll will stiffen.


It is a HUGE improvement! You should really go for it. After a few months of driving with M5 front/rear bars, I replaced my M5 rear bar with the adjustable Dinan bar set on the middle holes to gain a more neutral handling at the limit. That Dinan rear bar was only about $200. But even with the M5 rear, the M5 front was wonderful compared with stock. My wife noticed the difference just truning out of the driveway. (I'll need to have a discussion with her about her driveway exit speed later tonight!  )

Keep in mind that you don't notice the increased understeer bias unless you are at the limit during an autocross, driving school, or accident avoidance situation on the street. What you really do notice is the improved turn-in response and dramatically reduced body roll. While the addition of the rear M5 bar is subtle, the addition of the front bar is anything but.

Instructions for installing the front bar are here: http://www.zeckhausen.com/howto/bmwe39/swaybar_replacement.htm


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## bmw540i (Mar 30, 2003)

Guys what do you think about the Eibach sways are they worth it? Thanks. :dunno:


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## jvr826 (Apr 22, 2002)

Sheeeeeeeeeeeeeeit! You would have to tell me that the front is a huge improvement. I find the M5 rear bar a huge improvement over stock. The car feels so much more stable in the aggressive cornering I do alot of on the mountain roads near my home. But it feels a bit mismatched now.

Dave, have you done a front bar on 530 or 528? I'm wondering if the r&p setup is different enough that the install would be different for my car.

j



DZeckhausen said:


> It is a HUGE improvement! You should really go for it. After a few months of driving with M5 front/rear bars, I replaced my M5 rear bar with the adjustable Dinan bar set on the middle holes to gain a more neutral handling at the limit. That Dinan rear bar was only about $200. But even with the M5 rear, the M5 front was wonderful compared with stock. My wife noticed the difference just truning out of the driveway. (I'll need to have a discussion with her about her driveway exit speed later tonight!  )
> 
> Keep in mind that you don't notice the increased understeer bias unless you are at the limit during an autocross, driving school, or accident avoidance situation on the street. What you really do notice is the improved turn-in response and dramatically reduced body roll. While the addition of the rear M5 bar is subtle, the addition of the front bar is anything but.
> 
> Instructions for installing the front bar are here: http://www.zeckhausen.com/howto/bmwe39/swaybar_replacement.htm


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## DanB (Feb 20, 2002)

jvr530i said:


> Sheeeeeeeeeeeeeeit! You would have to tell me that the front is a huge improvement. I find the M5 rear bar a huge improvement over stock. The car feels so much more stable in the aggressive cornering I do alot of on the mountain roads near my home. But it feels a bit mismatched now.
> 
> Dave, have you done a front bar on 530 or 528? I'm wondering if the r&p setup is different enough that the install would be different for my car.
> 
> j


I don't think the M5 bar will fit your car. Dinan has two different part numbers for the E39 front swaybar... If they could use the same part, I don't think they'd have 2 PN's.

-DanB


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## DZeckhausen (Mar 11, 2003)

Dan is correct. You can't fit the M5 front bar on any of the I6 cars. It only fits the 540i.


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## Rgol (Nov 22, 2002)

You cannot install a //M5 front sway bar on the 528/530. The biggest OEM sway bar is the "//M-Sports Suspension II" front sway bar.

The 525i front bar is 22.5mm thick (or 24mm with Sport suspension) 
540i front bar is 24.5mm thick (25mm for Sport and 6-speed). The //M5 front bar is 27mm thick.

The thickest factory swaybar that is listed for the 525i/528i/530i is the "M-Sports suspension II" ( 31-35-2-229-420). That would get you a 25mm thick front bar (as thick as the 540i 6-Speed) yet it would have the proper bends to fit your car. 

You will also need a pair of p/n 31-35-1-093-108 rubber bushings (X2) which will fit inside the same metal brackets that are being used right now to hold the bushings for your 22.5mm front swaybar.


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## PropellerHead (Jan 3, 2002)

Rgol said:


> The 525i front bar is 22.5mm thick (or 24mm with Sport suspension) 540i front bar is 24.5mm thick (25mm for Sport and 6-speed). The //M5 front bar is 27mm thick.


 I read in Roundel that one of the things they changed for the outgoing sport model E39's in '03 was that they increased the swaybar thickness, used eurathane bushings and other suspension adjustments- stiffer shocks, etc.

Anyone have access to a recent enought ETK to confirm that?


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## DZeckhausen (Mar 11, 2003)

Rgol said:


> The thickest factory swaybar that is listed for the 525i/528i/530i is the "M-Sports suspension II" ( 31-35-2-229-420). That would get you a 25mm thick front bar (as thick as the 540i 6-Speed) yet it would have the proper bends to fit your car.


An important question to answer, before ordering and installing the 25mm front bar, is what is the diameter of the front swaybar that comes standard on the 528i 5-Speed? It would be no fun at all to replace a 25mm swaybar with an identical part!


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## jvr826 (Apr 22, 2002)

DZeckhausen said:


> An important question to answer, before ordering and installing the 25mm front bar, is what is the diameter of the front swaybar that comes standard on the 528i 5-Speed? It would be no fun at all to replace a 25mm swaybar with an identical part!


Exactly! I'm sitting tight to see if anyone responds to the ETK question above...


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## Rgol (Nov 22, 2002)

*I have a '99 528i Sport 5-Speed*

From my research, the front sway bar on a 525i/528i/530i is 22.5mm thick and *24mm with Sport suspension*.

So, you will be going from a 24mm to 25mm if you stay with OEM. I believe that the sway bar from Eibach and/or RD Sport is 27mm, which is what the //M5 front sway bar specs out.

So, you stick with OEM BMW or go aftermarket.

Robert


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## Ågent99 (Jan 7, 2002)

Rgol said:


> From my research, the front sway bar on a 525i/528i/530i is 22.5mm thick and *24mm with Sport suspension*.
> 
> So, you will be going from a 24mm to 25mm if you stay with OEM. I believe that the sway bar from Eibach and/or RD Sport is 27mm, which is what the //M5 front sway bar specs out.
> 
> ...


To the best of your knowledge, this should apply to the 530i as well, right? There are some differences between the 528 and 530 but I cannot imagine it would be in the area where the front sway bar would change.

Chris


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## DZeckhausen (Mar 11, 2003)

Rgol said:


> From my research, the front sway bar on a 525i/528i/530i is 22.5mm thick and *24mm with Sport suspension*.


Then for what option package is the 25mm M-Sport Suspension II shipped? Is that a Europe-only configuration?


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## PropellerHead (Jan 3, 2002)

DZeckhausen said:


> It is a HUGE improvement! You should really go for it. After a few months of driving with M5 front/rear bars, I replaced my M5 rear bar with the adjustable Dinan bar set on the middle holes to gain a more neutral handling at the limit.
> Instructions for installing the front bar are here: http://www.zeckhausen.com/howto/bmwe39/swaybar_replacement.htm


That settles it- I just ordered the Dinan rear and M5 front.

And the Dinan Front strut brace... :eeps:


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## Ågent99 (Jan 7, 2002)

PropellerHead said:


> That settles it- I just ordered the Dinan rear and M5 front.
> 
> And the Dinan Front strut brace... :eeps:


"A fool and his money are soon parted...."



Chris


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## DanB (Feb 20, 2002)

Ågent99 said:


> "A fool and his money are soon parted...."
> 
> 
> 
> Chris


Dude, quit being a bunghole. Sways make a big difference!

Hey, and where are pix of your intake!?

;-D

-DanB


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## PropellerHead (Jan 3, 2002)

Ågent99 said:


> "A fool and his money are soon parted...."
> 
> 
> 
> Chris


This from the guy who bought a cut up Honda intake and then bought ANOTHER CAI to replace it.


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## RonV (Nov 12, 2003)

This subject interests me, as I've been considering an upgrade to my 2002 530. I've been lured out of lurking, and this is long:

I believe the the M-Sport II suspension is included with the BMW AG M-Sport package, which includes the M-Technic front and rear bumpers. In the US, this wasn't available for most of the E39 run (although it was in Canada). However, the 2003 540 six-speed includes the M-Technic front and rear bumpers, and I think it includes the M-sport II suspension. Nonetheless, as you'll see below, on the 540, the M-sport II suspension has the same swaybar sizes, so the 2003 530i/6 has the same swaybar sizes as all the other 540 sports. Maybe the shocks and struts are different?

I did the research on available diameters in the ETK, plus Dinan:

M5 front
OEM 27mm

540 front
OEM non-sport 24.5mm
OEM sport and sport II 25mm
Dinan 27mm

525/530 front
OEM non-sport 22.5mm
OEM "for vehicles with payload increase" 23mm
OEM sport 24mm
OEM sport II 25mm
Dinan 25mm

M5 rear
OEM 16.5mm
Dinan 17mm adjustable length

540 rear
OEM non-sport 14 mm
OEM sport and sport II 15mm
Dinan 17mm adjustable length

525/530 rear
OEM non-sport 13mm
OEM sport 14mm
OEM sport II 15 mm
Dinan 17mm adjustable length

I think all the rear bars are interchangable, so on any model, your choices are 13, 14, 15, and 17mm.

I did a google search and found the following two helpful-looking sites:
http://www.grmotorsports.com/swaybars.html
http://www.theherd.com/articles/swaybar.html

Can anyone comment on their accuracy? I'm particularly interested in the claim on the second site (for Dave Z: it's an Impala article) that stiffness is proportional to 4th power of the thickness and inversely proportional to the 1st power of the length. That would mean that adjusting the length of the Dinan rear bar is only a touch-up compared to the effect of changing the thickness.


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## PropellerHead (Jan 3, 2002)

Patrick 520iAT said:


> :tsk:
> 
> This isn't helped by the fact that a friend of mine has a brand new NAV/TV unit, wiring loom etc. (all the parts basically) for a 2002 E39 ... And there is now a CD for Finland available. No, I will not do it.
> 
> ...


Dooooo eeeeet! I've had NAVTV for almost 3 years.. :bigpimp: Moohahahhaha!! :angel:


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## Patrick (Dec 23, 2001)

PropellerHead said:


> Dooooo eeeeet! I've had NAVTV for almost 3 years.. :bigpimp: Moohahahhaha!! :angel:


 

The corruption continues ... uch:



-


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## Ågent99 (Jan 7, 2002)

Patrick 520iAT said:


> The corruption continues ... uch:
> 
> 
> 
> -


You will be assimilated....:bigpimp:

Chris


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## e39540i6 (Oct 9, 2003)

Patrick 520iAT said:


> :tsk:
> 
> This isn't helped by the fact that a friend of mine has a brand new NAV/TV unit, wiring loom etc. (all the parts basically) for a 2002 E39 ... And there is now a CD for Finland available. No, I will not do it.
> 
> ...


What do you mean by this? A CD for what?


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## DZeckhausen (Mar 11, 2003)

e39540i6 said:


> What do you mean by this? A CD for what?


The NAVTECH map CD didn't cover Finland until the most recent release: http://www.navtech.com/UserOrdersServlet?action=viewProduct&productId=1024&continentId=EU


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## Patrick (Dec 23, 2001)

DZeckhausen said:


> The NAVTECH map CD didn't cover Finland until the most recent release: http://www.navtech.com/UserOrdersServlet?action=viewProduct&productId=1024&continentId=EU


 :thumbup:

-


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## bmw540i (Mar 30, 2003)

KCLARK said:


> bmw540i: i think your inquiry was just flat out skipped over because nobody here has any info on them (easier to discuss what you got).
> I too was waiting on some sort of read about the Eibach swaybars, because I plan to go with the Eibach sways. I have a 530i Sport and already have their springs and havent been disapointed so why not match it up with their sways kit since both F/R come as a package. I figured from your name you have a 540i, and I checked the Eibach swaybar diameters (for your car) and found they are similar to the M5 sways (28mm/18mm). Yeah I know they're non-adjustable, but as a suspension company I trust they know their sh!t when it comes to settings. I dont know pricing on them but the part number for your car is #2054.320, and should be able to get them from Tire Rack since they are a distributor.


Thanks for replying man... I got the Technik/Eibach sways installed on Tuesday they did reduce body roll significantly but when you push it hard it tends to understeer... I think that could be fixed with larger wheels and suspension upgrade.


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## Patrick (Dec 23, 2001)

Ågent99 said:


> You will be assimilated....:bigpimp:
> 
> Chris


I think that you are correct. I will know its bad when I order front and rear cup holders ...

Anyway, I just ordered the M5 rear anti-sway bar and bushings. :eeps:

My buddy Jari from the parts dept. always knows that something is up when I show up there with a yellow Post-It® note.

123 EUR for everything, but it is coming from Germany, so I will have to wait a little while. No worries. I plan to do the installation myself! :yikes:

-


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## Lscman (Aug 5, 2003)

From what I can tell, the Eibach 540i rear springs are stiffer than OEM sport and their fronts are DEFINITELY softer. I know the front spring rate is lower because their free length is longer but their compressed height is shorter. I think their swaybars are balanced for their spring kit. Their stiff rear springs should dial out understeer.


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## tsaros (Nov 24, 2003)

Patrick 520iAT-; 
Please let us know how it ends up and if the parts actually fit the car.
If it works well for you then i might mod my touring as well


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## Patrick (Dec 23, 2001)

tsaros said:


> Patrick 520iAT-;
> Please let us know how it ends up and if the parts actually fit the car.
> If it works well for you then i might mod my touring as well


tsaros: *Tjäna!* 

The parts were not in Sweden (that is where Finnish BMW parts departments get their orders from) so it is coming from Germany, and should be here by Friday. I will do the installation next week and post my opinions after that!

Stay tuned ...


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## tsaros (Nov 24, 2003)

Patrick 520iAT said:


> tsaros: *Tjäna!*
> 
> The parts were not in Sweden (that is where Finnish BMW parts departments get their orders from) so it is coming from Germany, and should be here by Friday. I will do the installation next week and post my opinions after that!
> 
> Stay tuned ...


Any progress yet ?


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## Patrick (Dec 23, 2001)

tsaros said:


> Any progress yet ?


Still waiting to get the call from the parts department - hopefully this week.

I will post an update when I get it installed and have some time to drive. I just hope that it stays above 0°C ...


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## Patrick (Dec 23, 2001)

The parts department just sent me SMS: the M5 rear bar + bushings is in. I will pick it up tomorrow and the installation will begin. :eeps: 

Lets see if Dave Z's "30 minute installation" holds water!  



-


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## tsaros (Nov 24, 2003)

Patrick 520iAT said:


> The parts department just sent me SMS: the M5 rear bar + bushings is in. I will pick it up tomorrow and the installation will begin. :eeps:
> 
> Lets see if Dave Z's "30 minute installation" holds water!
> 
> -


Patrick, your 30 minutes are up


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## Patrick (Dec 23, 2001)

tsaros said:


> Patrick, your 30 minutes are up


Sorry to keep you hanging ... :bigpimp:

The install will happen next Wednesday, at 13:00 EET, at a friend's garage - he fixes and repairs watercooled Volkswagens. He has a "killer set of tools" and a lift. The same guy installed my Eibach springs.

The delay is due to the fact that I will be on the road to middle Finland, Estonia and possibly to Stockholm for a meeting in the next few days.

I will let you know as soon as I have everything done and get some seat of the pants information. 

-


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## Patrick (Dec 23, 2001)

It is getting installed tomorrow morning - at the service department! :rofl: 

I know, I suck ... but the passenger side air bag sensor in the seat is being replaced, and that is ... easy to combine with the anti-sway bar install. :eeps: 

More details tomorrow afternoon!



-


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## Patrick (Dec 23, 2001)

*M5 rear anti-sway bar adds 8hp!*

Installed. It took 20 minutes. The roads are icy today (-5°C), but I did a little driving with ASC turned OFF.

What I did notice was that the back of the car does feel stiffer, almost like it is heavier. It does make the steering feel different as well. I suppose that is what I should have expected! I am happy ... Tsaros: do it! 

-


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## tsaros (Nov 24, 2003)

Patrick 520iAT said:


> Installed. It took 20 minutes. The roads are icy today (-5°C), but I did a little driving with ASC turned OFF.
> 
> What I did notice was that the back of the car does feel stiffer, almost like it is heavier. It does make the steering feel different as well. I suppose that is what I should have expected! I am happy ... Tsaros: do it!
> 
> -


Thank you 
Different in what way ?
Im having quite alot of bodyroll atm, im having my springs and dampers changed during next week to see if that helps any, if not then im going for the anti-swaybars as well.
Does anyone have a idea if the anti-swaybar from the M5 front will fit our tourings as well ?


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## tsaros (Nov 24, 2003)

Sorry about that question regarding the M5 front swaybar, thats what happens when you dont read


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## Patrick (Dec 23, 2001)

tsaros said:


> Thank you
> Different in what way ?
> Im having quite alot of bodyroll atm, im having my springs and dampers changed during next week to see if that helps any, if not then im going for the anti-swaybars as well.
> Does anyone have a idea if the anti-swaybar from the M5 front will fit our tourings as well ?


Different in that there is more understeer (I think that is the right word for it). I have been watching a lot of Top Gear to try and get these terms correct!

There is no ice on the roads today, so when I get out, I will get on it a little bit and see what else I can determine. So far, the best way that I can describe it is that it is different!

I would suggest that the combination of improved springs (and dampners) + the rear anti-sway bar will drastically reduce body roll. The Eibach spring alone did that for my POS.

What are you going install?

-


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## tsaros (Nov 24, 2003)

Im having Bilstein Sprint dampers and H&R springs fitted.
i choose to lower the front 40mm, hopefullt that will turn out nicley.
The back will be lowered 15-20mm havent decided on that one yet 
If you get more understeer with the rear swaybar upgrade then ill be doing the front first 
Thanks for informing me :thumbup:


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## PropellerHead (Jan 3, 2002)

tsaros said:


> If you get more understeer with the rear swaybar upgrade then ill be doing the front first
> Thanks for informing me :thumbup:


I think you'll get more OVERsteer- (the back swinging out) with a rear. The front may cause the car to 'push' (understeer). My experience was that the rear bar balanced things out VERY nicely. The front is being done as we speak, and I am keeping the Dinan adjustable bar to the most loose (least oversteer- counfusing, ain't it? :loco: ). I want to drive it awhile and see what the front bar does. I will adjust the rear tighter (more oversteer) if I need to achieve balance with the M5 front bar.


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## Patrick (Dec 23, 2001)

tsaros said:


> Im having Bilstein Sprint dampers and H&R springs fitted.
> i choose to lower the front 40mm, hopefullt that will turn out nicley.
> The back will be lowered 15-20mm havent decided on that one yet
> If you get more understeer with the rear swaybar upgrade then ill be doing the front first
> Thanks for informing me :thumbup:


That is pretty low! But you have chosen good shock absorbers to go with that.

After you have completed the lowering upgrade, post a message on VietSB's thread about lowered E39s:

http://www.bimmerfest.com/forums/showthread.php?t=45439

-


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## Patrick (Dec 23, 2001)

PropellerHead said:


> I think you'll get more OVERsteer- (the back swinging out) with a rear. The front may cause the car to 'push' (understeer). My experience was that the rear bar balanced things out VERY nicely.


Hmm. Maybe it was the slippery road conditions; it felt like the front was bitting more than before, and the back end was more balanced. And it is also likely, I have my terms mixed up ... uch:

In driving today in the wet (with non-studded 15" snows on) I can tell that the car feels a lot more solid in back. I took a few sharp turns on off-ramps at speed (+90km/h) and it was fantastic. It did not give me the feeling the back end was going to come around - just smooth.

I look forward to dry weather, summer tires + wheels and some twisties.

Now I need someone to talk me into a better front anti-sway bar and some uprated shock absorbers! 

-


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## PropellerHead (Jan 3, 2002)

Patrick 520iAT said:


> Hmm. Maybe it was the slippery road conditions; it felt like the front was bitting more than before, and the back end was more balanced. And it is also likely, I have my terms mixed up ... uch:-


I think you have it nailed, Patrick. What you are experiencing is the same thing I did- You took out the factory settings of the car 'pushing' (understeer) and balanced it with the new, M5 bar's thickness that creats more oversteer. You just induced a little oversteer to counter the factory's understeer- Am I making sense? :loco: 
It's not that you WILL get the rear to swing with a thicker bar, it's that increasing the rear diameter flattens the car's rear end in corners. What that does is put more pressure on the outside edges of the rear and thus- let's say- _enhances the chances_ of oversteer. That slight enhancement added to a car already tuned by the factory for understeer creates the very nice balance that both of us experienced when we changed the rear bar.


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