Front bushes - Solid Rubber vs Polyureathane

[kaanage]

Since I have totally voided my suspension warranty (I have a clunking front end thread that describes why), I am now looking at enhancing the front suspension behaviour of my Polo.

I was going to get the SEAT Cupra solid rubber bushes in the hope that I could get better braking stability (through decreased dynamic toe out) as well as improved steering response with minimal change.

With the warranty well and truly null and void, I am now looking into Polyureathane front bushes with built in offset so that I can get a similar effect to the Whiteline ALK kits that are available for the MkV and MkVI Golfs. As well as added caster, this would then let me run a stiifer front antiroll bar without reducing compliance on turn in. All of this should further improve the steering response as well as providing the benefits I am hoping for with the SEAT Cupra solid rubber bushes.

The downside, of course, is increased NVH and the possibility of squeaking if the lubrication for the Polyureathane bushes dries out (or gets squeezed out). This is my daily drive and I don't want to make the car too uncomfortable for family use.

Has anyone here had both the solid rubber bushes and Polyureathane bushes fitted to the front at different times to their cars?

I did post a specific Polo version of this topic in the Polo 9N(3) forum but I thought it might be a suitable general suspension topic. If moderators disapprove of the double enquiry, please delete one of the threads.

[rayray086]

Just to clarify, are you referring to all the bushes that you can replace in the front suspension?

Polyurethane is best used when you do not want any flex. Components like the strut top mount and engine mounts are OK to use polyurethane mounts as there's no lateral flex and they just act as dampeners. Control arm bushings however rely on the flex that rubber provides, and polyurethane here are arguably not the best choice. I've heard of accounts where the polyurethane control arm bushings fail prematurely (tearing) due to the amount of lateral flex occurring at those joints (especially on lowered cars).

I used polyurethane for my rear strut top mounts on my Mk3 and in about a month's worth of use, it started squeaking. It wasn't super loud but I could hear it over all my other rattles and it just got annoying. I swapped them out for standard rubbers and the sound went away. Feel was good as well since they were new. I had heavy duty rubber for my front strut top mounts and they were beefy as. Car felt very stable and responsive (I also did a whole lot of other bushing replacements including R32 solid rubber control arm mounts) and there were no annoying noises either.

I'd say go with the uprated solid rubber OEM ones from the Cupra!

[kaanage]

Thanks - I meant the lower control arm bushes.
The only reason I'm considering polyureathane bushes is for the offset option for the rear mounts so that I can improve the steering.

With the tearing you mention, were they single piece bushings like the ones in the Whiteline ALK kits?

[gavs]

Polyurethane is no good (as rayray has mentioned) for applications that require twist, i.e LCA is a classic example.

urethane bushes perform best in compression, i.e a strut mount, a shock absorber bushing, a front LCA busing on the Polo or in a double wishbone arrangement. This is due to the molecular strcture and other fancy chemistry based things which I could go into great detail about I am sure, but neither I or the suspension engineers sitting 10m away from me could be bothered to write down Urethane also has a memory, not good for twisty twisty bushings because it can take this set memory after being too deflected which will generate knocking and a loose front end. This lack of compliance will actually result in more premature wear than if you used the old, split rubber Mk4 Golf bushes and also a looser front end after a few weeks of Melbourne's brilliant road surfaces.

The other issue is (also, as rayray mentioned) the tearing when put under a torqued load. My suggestion would be to go for the solid bonded rubber for the rear control arm bushes and urethane for the front LCA bushes. The fronts work under compression with being a pivot point. The stiffer front bush should help the dynamic toe issue (dependant on the duro of the urethane you go with) along with the lateral flex being reduced with teh sild rubber bushing. The stockies generally have lateral and medial slits in the rubber for the NVH issues.

[kaanage]

This all seems to point to the Whiteline AntiLift Kit being a bad idea unless you could replace their polyureathane bushes with rubber ones.

[Whiteline]

Hi,

the only problem having rubber in an anti lift kit over polyurethane is that it would defeat the purpose in ways as rubber is softer and will flex further when braking and turning it would flex and change wheel alignment settings and you would lose castor due to this.

Also we have made voiding in our Antilift kits and have had much success worldwide with the sale of these.

Here is a link to another thread on this forum with great reviews on the antilift kit http://www.vwwatercooled.org.au/foru...e-63326-5.html

[kaanage]

I've read that thread + the Subaru article you have, which is why I'm interested in the 1st place.

What's "voiding"? Are they gaps in the bushes to allow controlled flexing?

[bluefrog]

Hi Whiteline, I didn't realise that you posted on this forum, but seeing that you do I'm keen to find out more about the following because I've just recently had the Whiteline bushes installed on my R ..

Where is the product made?

An experienced suspension technician recently told me that he had personally seen problems with Whiteline bushes a few years ago, where the bushing/s had failed and resulted in the front end becoming loose. He said that he suspected that the problem should now be resolved, but I'm hoping that you can elaborate on this issue as I haven't read about it before, or done a google search yet.

Thanks in advance.

[kaanage]

The other issue with the ALK is that it isn't available for my car

That's why I've been asking about offset bushes.

[rouge71]

I have off set polyurethane bushes in both my Gti as well as , just fitted, my wife's Ibiza. The In the Golf they are 2 piece, to allow even better movement than standard. In the Ibiza the shape of the bush is such that it allows decent movement.

I don't notice any extra noise or harshness.

I don't use Whiteline anymore due to several issues I have had and I think it is not Australia made. I think the Anti lift kit is over priced, as I explained in this thread:

http://www.vwwatercooled.org.au/forums/f149/whiteline-anti-lift-kit-fitted-freakin-awesome-63326-5.html

[kaanage]

What brand are your Golfs' polyureathane bushes, rouge71?
And welcome!

[rouge71]

What brand are your Golfs' polyureathane bushes, rouge71?
And welcome!

Super Pro. They seem to very well made and have none of the drawbacks of the European polyurethane. Australia made as well, it seems.

[kaanage]

Did you consider their anti-lift kit (SuperPro's, that is)?

[rouge71]

I wasn't aware that they did such a thing. I bought their off-set bushes and fitted them to get as much caster as possible.
This made the steering have more 'feel' and as well as having more grip, the ESP is not cutting in all the time anymore.

If I wanted to reduce the anti-geometry, I would fit spacers between the alloy bush housing and the subframe, to move the back of the control arm down, essentially what an anti lift kit does.

Personally, I prefer to keep the anti-geometry as standard. I drive in Germany during the week and find the car more stable under hard braking from over 200 km/h to 50 km/h. Personal preference though.

[kaanage]

I didn't know that they did an ALK either until I looked at their Golf MkV and VI products after you said your car had their offset bushes. I agree with your comment about the "anti-lift" definition - I guess "pro-dive/squat" wouldn't wash over so well with the masses who think increasing stiffness automatically => improved handling/grip

I'm guessing that the advantage of an ALK over spacers is that the part is certified?

So did you have the offset bushes installed to push out the rear of the control arm as much as possible?

BTW Stable braking is what I'm looking for!!