Front Control Arm Bushing Choices

[unluky]

In my quest to tighten up my steering, but next sights were the FCAB's.

I see people talk about SuperFlex, Meyle, Powerflex, and OEM. Sounds like OEM are doomed to fail again, so I wondered what the pro's/con's of the others were?

I put an energy suspension full bushing kit in my 300ZX years ago and loved it (except the increased rear end noise in the cabin), so I am not opposed to a tighter/stiffer feel to my car. Do not track or anything, just want to tighten up what I feel is still a little "wandering" steering during straight line driving.

Any recommendations or things to consider?

[GuidoK]

Originally Posted by unluky

I see people talk about SuperFlex, Meyle, Powerflex, and OEM.

There are some more: strongflex, Whiteline (and some smaller suppliers)

I think you first have to make up your mind if you want rubber or PU (I take it that you dont want solid bushings like delrin or aluminium), and then decide on the hardness.

[unluky]

I think I want PU, unless that is not a good option for these cars? Loved them on my ZX. Do not want solid for sure and I figured rubber would fail again sooner or later?

I was looking at the 2 piece ones that you lube in between, but could not find a lot of info good or bad on them really.

[Karacticus]

Here's something to consider for the non-///M

http://www.treehouseracing.com/new/?...rm-bushing-set

[GuidoK]

^that's solid, so that's not what he wants.

Also bloody expensive!

I'd go for something like powerflex. Lots (and lots!) of people use those.

[unluky]

So the 2 piece powerflex are pretty popular and proven? Those were the ones I was looking at and wanted to make sure people we happy with them.

[GuidoK]

I've had them for 3 years and are still great.
I think in general powerflex is the biggest distributor for pu bushings for bmw's.
I don't want to say that other marques are rubbish: half the bushings in my car come from strongflex (they have more sorts, are cheaper but powerflex is both better on some points and worse on some points), and I've also seen nice stuff from superflex.

As with all PU bushings, you have people who are in favour, and who are against.

Mostly people can complain about noise. All PU (and solid) bushings have to be well lubricated with copper grease (it comes with the bushings).
I don't hear any noise coming from the pu bushings (and I replaced all 21 in my z4), so that may also be an install/craftmanship issue.

Also some people complain about installing, but the biggest thing is obviously getting the old bushings out. But if you installed bushings before you know what to expect and what tools you'll be likely to use.
Without the right tools&experience every bushing install can be a pain.
If you're planning to do more bushing jobs in the future yourselves, get a universal bushing install kit. something like this:
http://www.ebay.com/itm/Universal-Pr...item4d12482ad3
For the odd placement in narrow spaces you'd probably need to use sockets&washers, but this gets you a long way on most vehicles and spots. You get a lot of different diameters pressing cups in a kit like this, and a kit like this is strong enough to get most bushings out (at least on a bmw )

To get the fcab's off the arm themselves, you might want to use something like a cheap generic puller or so. Sometimes the rubber clamps just too much to get them off by hand.

[unluky]

Yes, I installed a full Energy Suspension kit in my 300 including the sub frame and differential bushings, so I have experience with the installs and also making sure they are lubed. I have had them in my 300 for 7-8 years now and still have no squeaks or issues with them. Made the car much tighter and except for a little more differential noise in the cabin - have no negatives to speak of.

Thanks for the info. Mainly just did not want to wing something based on marketing chatter only to find out the ones I bought had known issues I was missing online.

Thank you!

[3002 tii]

Just get the OEM Z4M FCAB's, the offset design will give you MORE caster over the Non-M FCAB's. I track my car heavily and I was able to get 40k out of my factory ones. I would not go fully poly, car might feel tighter but poly never lasts as long as rubber.

[GuidoK]

Originally Posted by 3002 tii

but poly never lasts as long as rubber.

That's not the general experience.
The stock rubber ones are a known general bmw part to fail (thousends of reports), and I've never seen a powerflex one fail.
PU does not fatigue and does not age imho.
Also the rubber ones are of a design that they stretch; the pu ones (the powerflex ones at least) are a real bearing.

Also I don't know why you'd want more caster?
More caster means less steering response entering a corner and more steering response exiting a corner (so basically more stable thus less manouverable). Imho that doesn't weigh up to the camber gain effect, but that all might be a personal preference.
If you still want the larger caster angle, you can always go for a PU version one. There are several suppliers of those.

Originally Posted by unluky

so I have experience

Do you have any preference for a particular stiffness?
Powerflex has 2 versions: shore 80A and shore 95A (I think)
If you look at the shore80A (already a little bit stiffer than stock rubber), only the insert is 80A (purple), the black outer piece is 95A:

you can get the outer piece in aluminium also.
The powerflex black series are made from shore95A (at powerflex purple means 80A and black means 95A), so they also have a black insert.
Be sure to get the 66mm versions! (the 60mm versions they list are for early e46's only!)
The stock ones (shore80A) are not really that hard; you might describe them as always driving a brand new car. You know, when you drive a brand new car and everything is just really tight.

At strongflex red means shore80A and yellow means shore90A.
Their design is a bit different (the inner part is hard, the outer part is soft).

And with pu bushings: if they should fail (or you'd want a different stiffness): installing new ones is much easier.

[3002 tii]

Originally Posted by GuidoK

That's not the general experience.
The stock rubber ones are a known general bmw part to fail (thousends of reports), and I've never seen a powerflex one fail.
PU does not fatigue and does not age imho.
Also the rubber ones are of a design that they stretch; the pu ones (the powerflex ones at least) are a real bearing.

Also I don't know why you'd want more caster?
More caster means less steering response entering a corner and more steering response exiting a corner (so basically more stable thus less manouverable). Imho that doesn't weigh up to the camber gain effect, but that all might be a personal preference.
If you still want the larger caster angle, you can always go for a PU version one. There are several suppliers of those.

I totally disagree, maybe if you're running excessive caster but my suggestion of OEM bushings would not be considered excessive. More positive caster is going to provide more high speeds stability and more dynamic negative camber. These thousands of reports on OEM bushings, I doubt any of them were premature. Bushings are wear and tear items, simple as that.

Also talk to any experienced racer and you'll see most prefer OEM rubber over full poly. Here's pics of E36 and Z4 Powerflex bushings both fail before 10k.

[GuidoK]

Originally Posted by 3002 tii

Also talk to any experienced racer and you'll see most prefer OEM rubber over full poly.

So? you did some statistical review?
Bit hard to back up that claim imho.
Also not relevant as the TS says he's not going to race his car.


The failed powerflex fcab I haven't seen before, but I'm sure that for every picture you post of a failed PU bmw fcab, I can probably post 10 (100?) failed OEM rubber fcab bushings. Meyle doesnt make a HD version for nothing; it's a known weak spot for 3 decades of bmw's.
So I'm sure that whatever you're pointing at, it will certainly not be a matter of 'most'.

Besides, the TS has extensive experience with PU bushings in the past (albeit on another car), so he is well informed enough on what he's going to get. He asks specific information on what brands and types he can choose from. So lets give him that information that best completes his question.

In the end nothing is 'indestructible'.
PU bushings imho only break when they experience overload, but not by ageing fatigue (as normal rubber does) or motion fatigue: as they act as a true bearing, unlike the rubber bushing which is stressed/compressed (or twisted) with every movement of the control arm.

[3002 tii]

Originally Posted by GuidoK

So? you did some statistical review?
Bit hard to back up that claim imho.
Also not relevant as the TS says he's not going to race his car.


The failed powerflex fcab I haven't seen before, but I'm sure that for every picture you post of a failed PU bmw fcab, I can probably post 10 (100?) failed OEM rubber fcab bushings. Meyle doesnt make a HD version for nothing; it's a known weak spot for 3 decades of bmw's.
So I'm sure that whatever you're pointing at, it will certainly not be a matter of 'most'.

Besides, the TS has extensive experience with PU bushings in the past (albeit on another car), so he is well informed enough on what he's going to get. He asks specific information on what brands and types he can choose from. So lets give him that information that best completes his question.

In the end nothing is 'indestructible'.
PU bushings imho only break when they experience overload, but not by ageing fatigue (as normal rubber does) or motion fatigue: as they act as a true bearing, unlike the rubber bushing which is stressed/compressed (or twisted) with every movement of the control arm.

I have as much statistical evidence as you, only difference is I'm not nearly as defensive as you LMAO. I offer up my opinion based on my personal experience and observations. I've talked to many racers in the paddock and the general consensus is oem rubber last longer than Powerflex PU. I don't dispute that poly feels tighter but it's moot if they prematurely fail. And if you factor in cost of alignment for every time you have to replace the bushings, then it's even less worth it IMO.

What I can tell you is that OEM rubber bushings last 40k if not longer. Anything beyond bar doesn't dictate weakness IMHO as these are wear and tear parts. What I have seen though is Powrflex bushings fail in half the amount of time. You mention overload as being a possible reason and I think that's about right. Most of the failures I've seen or read about occur when 1) the car went almost full poly on most bushings (which isn't unheard of considering owners typically replace multiple bushings at once and if you're going to go poly for one, why not all?) or 2) they lost rigidity under heat usually from track conditions.

You're right nothing is indestructible, both rubber and poly fail. I'm just a firm believer that rubber will last far longer and I'll take trade off over the performance benefits poly has to offer, especially since you pointed out OP is not tracking his car so a longer lasting rubber bushing if anything seems MORE fitting.

[GuidoK]

Originally Posted by 3002 tii

I have as much statistical evidence as you, only difference is I'm not nearly as defensive as you LMAO.

I think the biggest difference is that I read what the TS wants and looks for?
It has nothing to do with being defensive. I just don't agree with your opinion, and I point out that you make some claims that you cannot possibly back up and therefore have no meaning. 'I talk to lots of people too'..... That has no real meaning. At least it doesn't impress me.

And if you factor in cost of alignment for every time you have to replace the bushings, then it's even less worth it IMO.

Why would you want to do that? The bushing (the fcab) is not an adjustable piece. Not for his car. The only time that you need to do that is if the car was aligned previously with a severe worn bushing (which is not a logical thing to do). Or bumped into things....
And replacing an insert for a powerflex pu bushing (ìf it would fail) is a matter of minutes. You unscrew the lollypop, and you put in a new insert...by hand!
Easy as that!

What I can tell you is that OEM rubber bushings last 40k if not longer.

And I can tell you the same about PU bushings. So what's the point?

and I'll take trade off over the performance benefits poly has to offer,

And that is exactly the point. The TS says that he wants the performance benefits. Just read what he wants to achieve. It's about his wishes.
He wants to tighten up his steering. He wants to know what alternative brands there are and what the differences are. So I think we should point thàt out. He knows what to expect with OEM. He already has that. And he already has experience with PU bushings.

[3002 tii]

Originally Posted by GuidoK

I think the biggest difference is that I read what the TS wants and looks for?
It has nothing to do with being defensive.


Why would you want to do that? The bushing is not an adjustable piece. The only time that you need to do that is if the car was aligned previously with a severe worn bushing (which is not a logical thing to do). Or bumped into things....
And replacing an insert for a powerflex pu bushing (ìf it would fail) is a matter of minutes. You unscrew the lollypop, and you put in a new insert...by hand!
Easy as that!


And I can tell you the same about PU bushings. So what's the point?



And that is exactly the point. The TS says that he wants the performance benefits. Just read what he wants to achieve. It's about his wishes.
He wants to tighten up his steering.

I read what OP wants but I'm giving him all sides so he can make a fully informed decision. Anyone will take performance gains all things being equal but not at the cost of less reliability. Whatever man, agree to disagree. Both bushings fail, clearly YMMV.

Lastly if you read his post as carefully as you claim, you'd notice his issue of wandering steering yet I don't see anyone addressing other possible causes for this like his tires, current alignment settings, etc. And going back to new bushings, oem rubber or poly would tighten up his steering since any worn bushing over time would lead to the symptoms he's describing now. People rave about how whatever aftermarket mod improved things vastly not realizing maybe his/her oem piece was due for replacement. When was the last time someone said their brand new car had vague steering?

I'm done with this thread. Feel free to push your point harder.

[GuidoK]

yet I don't see anyone addressing other possible causes for this

You didn't either... And yes that could be literary any component in his suspension/wheels if it would be the cause of a definitive failure or misalignment. But it could also be that he feels the OEM system/components aren't tight enough.
There can be a big difference between OEM bushings and PU (which doesnt get soft over time in my experience (I have compared identical brand new and well used 3 year old PU bushings and they're the same in stiffness, no degrading), and some people are looking for more feedback from their suspension. I thought the difference was very noticeable (also in the arb bushings), and everything is still in one piece after 4 years. No failure, but (verified as written above) also no sign of ageing/change in stiffness (which is the main advantage of PU imho)
I'm guessing that if people want to tighten up or modify their steering they have checked if something was physically wrong on the car in the first place. Or at least that's what I would do.


nice argumentum ad hominem at the end btw.

[unluky]

Yep - got rid of the run flats and that was all of the tramlining and most of the wondering. Alignment was in spec and the car handles 100%, I just feel like there is a shade bit of wondering under "neutral" driving conditions. Nothing terrible, but I notice it. I drive my other cars for a few days and then come back to the Z4, I really feel it again. Not like I am going to lose control or anything, just a tad more correction than seems normal.

Cornering it feels glued to the road and sure footed, so I was looking for things that maybe tighten up under load and loosen up under neutral wheel and these seem to fit the bill. Car has 70K on it, so wont hurt to change them anyway and I am the type of guy that will probably change out all bushing eventually, so this seems like a no brainer to go ahead and do.

Appreciate ALL the feedback on both sides - that s the kind of info I was looking for. When I find it - I will report back.

[unluky]

After my first cruise with the PowerFlex FCAB installed, I think maybe it helped. Will have to drive it for awhile to make sure, but I sure felt like it did today. Of course I also rotated my tires (side2side), installed new sway bar bushings up front and a new M wheel, so I need to let all that sink in and get comfy before I call it fixed. Felt good tonight though! Thanks again for all the advice.