Front sway bar recommends ??

[TurnAround]

Ok, so the front struts, and the rear shocks.. are gonna get replaced next week. 85k. They're done. Toast. Going with Non-Sport again (what I have now).

The thing is, I think I might also go for a beefed up front anti-sway bar. The 'sport' X uses the same bar as the non-sport, so I can't just upgrade that way.

Tried to search on front sway bars, but got nadda. Do you guys have any recommendations for an after market thicker stiffer front sway bar that has a good track record (folks have actually used, and like a lot)? All I want to do is kill a little of the body roll over stock. Other than that, all is good in the world and I love my X!

Thanks.

[cfmistry]

For some reason I thought the sport suspension had a thicker sway bar, but I checked out the part numbers on realoem and you are correct they are the same. You can look into the PowerFlex ES bushings to stiffen up your ride a little.

-Cyrus

[TurnAround]

From what I understand, the rear sway bar is thicker on the sport, but not the front. Interesting. Maybe BMW has some engineering behind that that makes it counter intuitive. I'm thinking... the front is what I need to stiffen eh?

[JCL]

The standard vehicle is set up to understeer, partly for safety with respect to the vast majority of drivers. Adding roll stiffness to the rear (as with the sport) will reduce that understeer.

Conversely, putting in a stiffer front sway bar (without touching the rear) will just increase the understeer. Probably not what you want to do.

[PropellerHead]

Originally Posted by JCL

Conversely, putting in a stiffer front sway bar (without touching the rear) will just increase the understeer. Probably not what you want to do.

+1

I have installed Eibach F/R sways on a 3.0 sport and my 4.8. I like the combo a lot, but it does stiffen the ride. Something that was tough but bearable on the 3.0 but downright needed on the 4.8.

[jst2878]

i have a rear eibach swaybar with bushings. practically brand new. i will sell it cheaper than anywhere else if u are interested. install time is around 40 minutes.

[TurnAround]

Originally Posted by JCL

Conversely, putting in a stiffer front sway bar (without touching the rear) will just increase the understeer. Probably not what you want to do.

Hmm.. me no like understeer.
What you are saying makes sense, but, then how do I cancel the body roll in the turns, without making the ride harsher, and not increasing understeer?

[JCL]

Originally Posted by TurnAround

Hmm.. me no like understeer.
What you are saying makes sense, but, then how do I cancel the body roll in the turns, without making the ride harsher, and not increasing understeer?

You stiffen up the rear, to reduce (not cancel) body roll without increasing understeer.

Making the ride harsher will be a natural consequence of that, though. Everything is a trade off.

To cancel body roll you would require an active suspension.

[TurnAround]

Originally Posted by JCL

You stiffen up the rear, to reduce (not cancel) body roll without increasing understeer.

So how about this; I replace the front struts with new OEM non sports (I'd like no less than my original ride quality back, so I'm nervous about going to sport shocks and springs), inspect and possibly replace the front sway bar bushings, replace the rear shocks with OEM non-sports, but then consider putting the OEM rear sport sway bar in the back (or possibly after market bar). ??

One thing I've never been able to work out tho; Why would a stiffer sway bar make the ride harsher? To be specific, its the little rumbly bumps in our town that are annoying. They're no more than 3/4" high, and most are 1/2". Its just that there's lots of them, its not that they're very gnarly. If one tire hits a bump that size, while the opposite wheel remains at the same elevation and planted, then the sway bar is only being asked to move a very small amount.. which it seems like it would willingly do.. hence, no added harshness. As compared to cornering where the vehicle is compressing on one side by, say, an inch or more, and traveling upward on the other side by the same amount. That's 2" total. Then the bar would really kick in.

So, what we're saying is that these bars are so stiff, that even 1/2" is strongly resisted? Just trying to learn. I actually have no idea. I only understand the very basics on sway bars.

[PropellerHead]

Originally Posted by TurnAround

So, what we're saying is that these bars are so stiff, that even 1/2" is strongly resisted? Just trying to learn. I actually have no idea. I only understand the very basics on sway bars.

Essentially it stiffens the ride because the two sides are connected by the sway bar. The thicker the bar, the stronger that connection and the less flex allowed between the two sides. From how stuff works:

If you don't have a stabilizer bar, you tend to have a lot of trouble with body roll in a turn. If you have too much stabilizer bar, you tend to lose independence between the suspension members on both sides of the car. When one wheel hits a bump, the stabilizer bar transmits the bump to the other side of the car as well, which is not what you want. The ideal is to find a setting that reduces body roll but does not hurt the independence of the tires.