Powerflex - things to think about

[CovKid]

I have a love/hate relationship with powerflex bushes and have never fully subscribed to the notion that powerflex is always better than an OE rubber bushes.

Powerflex make bushes for probably thousands of cars and its doubtful that they have had quite as much testing in situ on every vehicle compared to stock ones - mostly they are just close copies. However, accuracy in terms of measurements and indeed the flexibility of powerflex bushes can play an important part and one should not 'assume' that the swap is actually an improvement. I wouldn't question their longevity or capabilities but you do need to consider how much loading is induced on surrounding surfaces when replacing old rubber mounts etc and whether they are accurately made. It does make a difference. This guy covers what i'm trying to say very well:

http://www.youtube.com/watch?v=_z6OEohnPKw" onclick="window.open(this.href);return false;

Worth thinking about. He does highlight some of the concerns I have about the 'fit' and hardness of some powerflex items. In some areas I wouldn't hesitate to use them but in other areas I remain highly sceptical. Certainly I wouldn't just swap everything for powerflex without considering the above and doing the measurements. Put it this way, Brickwerks were not at all happy with the original ones made for the nose end on T25 gearboxes and now stock a modified one.

You could ofcourse just do this, as I had to on a Beetle once!!! http://www.youtube.com/watch?v=GczwCTzO5xk" onclick="window.open(this.href);return false;

[bigherb]

I wouldn't question their longevity or capabilities but you do need to consider how much loading is induced on surrounding surfaces when replacing old rubber mounts etc and whether they are accurately made. It does make a difference.

That is the most important part. Vehicle manufactures usually know more about the relationship of their parts than the "it's an upgrade so it must be better" nobs.

[CovKid]

You can also cast your own - using a new OE part as a base to cast from. Tadge fiddly but lots do just that, particularly stateside when original bushes or mounts are no longer available.

[Simon Baxter]

I'm sure if you took a superpro Bush from 5 years ago and compared it to a new powerflex Bush It would be a similar test.

[AdrianC]

How often is it a choice between genuine/OEM and "uprated", though? Usually, any choice also involves repro/pattern, of varying degrees of chocolateness.

I _would_ question the longevity of the various "uprated" bushes, though. My old Saab had purple plastic lower front damper bushes. They'd worn so oval that the inner sleeve was nearly all the way to the outer sleeve. I don't know how long they'd been in, sure - but they were the most knackered bushes on the entire car.

One thing that drastically affects the longevity of bushes - where the weight is when they're fully tightened. If there's no specific info (the rear dampers for the 205 give a specific pin-to-pin dimension, to the mm), then they should generally be done with the weight on the wheels, so they sit in the right "rest" position, rather than pre-loaded.

[CovKid]

Yep. Its not about whether one type wears better than another either, its about the actual design of them. In a lot of cases you can get away with copying the original bush and making it out of polyurethane (as in powerflex replacements) but in others its just not a good move at all as they end up dragging on surrounding components unless the profile is altered to suit. This was my point in showing one being reshaped on a lathe. I've seen that done a few times now. Exaggerated wear on polyurethane bushes is mostly due to them being too tight or the wrong shape to start with.

Powerflex bushes can induce a lot of squeaking too and worse than rubber bushes if they're not the right shape. I had intended to fit powerflex bushes when I changed my rear trailing arms but hit the problem shown on the wishbone in the vid. You needed a team of men to move the trailing arm with those fitted. They should not have to 'wear in' to that extent. In the end I decided to just fit OE ones and all was fine. An anti-roll bar is a different matter - I can see the sense in that but where theres some kind of moving axis I think you have to be way more sceptical or at least CHECK that there is movement where it is intended. Unless you do that, not only is movement impaired, handling too is affected and you're probably increasing noise inside the bodyshell too. These plastic bushes aren't cheap wherever you go and I wouldn't want to be spending £35-£50 for a bush thats worse in some cases than on OE one. Yes I could alter the profile on a lathe but for that kind of money I expect it to be spot on out of the box. They are definately not the wonder product claimed by the manufacturers.

[Titus A Duxass]

I've got them fitted all over except on the rear swingers.
They've been on for a number of years - no squeaks and the handling is still sharp.

Admittedly my bus is a toy/holiday vehicle and not a day driver.

VW might have known better 30 years ago but times and technology change.

Maybe we should have stayed in the trees?

[California Dreamin]

In support of what Ralph is saying.....how is it that Volkswagen themselves thought it necessary for some of there bushes to be voided (have spaces in the rubber to flex) whilst there Powerflex replacement is solid and aplauded for it's stiffness and resultant 'sharp handling'. Volkswagen wouldn't have spent millions in research and developement of components and their relationship to others, if it wasn't necessary.

Martin

[AdrianC]

In support of what Ralph is saying.....how is it that Volkswagen themselves thought it necessary for some of there bushes to be voided (have spaces in the rubber to flex) whilst there Powerflex replacement is solid and aplauded for it's stiffness and resultant 'sharp handling'. Volkswagen wouldn't have spent millions in research and developement of components and their relationship to others, if it wasn't necessary.

Different aims, I s'pose - some people want very stiff and harsh, others want compliant and smooth.

[Titus A Duxass]

In support of what Ralph is saying.....how is it that Volkswagen themselves thought it necessary for some of there bushes to be voided (have spaces in the rubber to flex) whilst there Powerflex replacement is solid and aplauded for it's stiffness and resultant 'sharp handling'. Volkswagen wouldn't have spent millions in research and developement of components and their relationship to others, if it wasn't necessary.

Different aims, I s'pose - some people want very stiff and harsh, others want compliant and smooth.

Which is what I have with power flex.

[CovKid]

There is a world of difference between having a stiffer more precise suspension, which can for instance make for better performance on a track or on motorways at speed than one that does not work as intended at all.

I have to agree with this guy with respect to trailing arms and wishbone bushes. Modern materials can be great if well made and attention paid to the correct shape, but on pivot points they can bind, inhibit free travel and even need replacing a lot quicker as a result. If you wanted to slow down or limit travel it doesn't take a rocket scientist to see that you would work on the springs and shocks, not fit tight bushes which would at best, be short term and worst, wholly incorrect.

If the poly bushes have the correct profile they CAN be better than stock on pivot points but at the moment, many of these urethane bush replacements are a poor replacement as there hasn't been the investment there in terms of trials. The fact that the gearbox bush is now modified to provide better movement (and I gather Simon was part of that change) is proof that these bushes still have a long way to go to match the exacting dynamics involved. Because the material is so much different, in some areas it is not sufficient to just replicate the shape of original bushes or produce ones without voids which actually contributed to performance and/or reduce vibration.

These bushes are not complicated to make. Indeed more and more manufacturers seem to be springing up with such good returns to be had and you can even make your own, but it does not follow that they are by any means a like-for-like replacement or by default, an improvement in every application.

I should add, that if you haven't watched the video I posted, you may miss the points being made here. Not everyone here seems to have got the point by the look of it. Unfortunately some of the powerflex bushes available are not up to the job as they are and will require machining to get a good fit. For the money involved in buying and refinishing them, it seems overkill to me. They should be right from the outset.

Superpro isn't available for T25s as they only really concentrate on modern vehicles or for race purposes so its not as if you can just buy another make. For pivoting arms, you either have to fit stock or spend time getting the poly ones reworked. Personally, for the time and silly money involved, I'd just fit stock and leave poly bushes to more suitable locations , at least until they produce ones that work, out of the box. Certainly buying a whole set of poly bushes without checking everything post-fit seems madness to me.

[Simon Baxter]

Okay.
A few things.

a) If SuperPro had answered the phone or any e-mails when I wanted to get polyurethane bushes for the T3 made then maybe SuperPro could be taking advantage of one of our biggest sellers right now, but they didn't.

b) I asked for Powerflex (as they answered the phone and e-mails) to develop the T3 bushes in a time when there wasn't much in the way of parts available for the T3, we had expensive VW stuff [at the time] or cheap rubbish from the usual suspects. I do the donkey work, trial fitting, road testing, taking pictures, measuring, photo-ing...

c) I think since development of the first bush until now [6 years?] our total warranty claims for parts that have failed in one way or another is about 2. I just asked Michael and he thinks the same, they don't fail. The ones we have swapped were due to cracking, they were ARB to body bushes and swapped under Powerflex's lifetime warranty.

d) I have never heard a Powerflex bush squeak. Ever.

e) Horses for courses, some people want nice suspension, some don't, some want to go to GSF and get some special bushes that last 6 months, some don't.

f) I agree that Polyurethane isn't right for everyone nor just because every bush is fitted with polyurethane does it make it any better, I personally on my own van have rubber radius rod bushes and original Lemforder wishbone bushes but everything else is Powerflex. Is my ride noisy? no, Uncomfortable? no. Do I suffer from vibration or harshness, No, does my van fly around corners, yes. Is it kid proof? yes, no complaints from the kids nor 'ar lass.

g) With regard to the gearbox mounting, again this was something we asked Powerflex to develop. We never sold them until the design was right, we never sold them without the voiding. There was a mistake and a gearbox mount was released to the public before it was ready. We never sold them.

h) I had to trim some early lower ARB bushes, I informed Powerflex and they modified the mould. Simple. Since then I have never had to trim a Powerflex bush.

So, I am very happy with Powerflex and the parts they produce. We don't suffer warranty returns, we sell load of them and any issues no matter how big or small are resolved. Of course we are never going to convince the people who use copper plumbing fittings for coolant pipes or washing machine drain hose for breather pipes but most people see and feel the benefits and enjoy the sharper handling and longevity they offer.

[Titus A Duxass]

[clift_d]

[CovKid]

The point is well made then, powerflex doesn't suit all applications and there will no doubt be improvements IF, And its a big 'if', people point out where things are not quite right . As Simon points out, the gearbox nose bush was altered as he wasn't happy with it but I suspect a trader is likely to carry more clout on that score. A backstreet mechanic is likely to be stuck with whats on offer. This isn't a dig at you or parts you sell by the way Simon - more a cautionary note as more parts become available in the market in differing materials - from whoever. We are increasingly seeing a plethora of things (including parts) being copied in the far east and in my experience you have to be on your toes when it comes to parting with your money and indeed in assuming that what you're buying will be better than the lower-priced item. It depends wholly on what it has to do. Chocolate bearings sold by national parts outlets are just the tip of the iceberg.

Powerflex do actually provide a copper grease with their bushes (note that this is not the case with OE rubber ones) to minimise friction and potential squeak. GT85 which is silicon based also helps so I'm told. In the meantime, I'm about to fit powerflex antirollbar mounts. Its not a job I particularly relish revisiting and they will do the perfectly well.