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Author: Subject: Polybushes....are those correct?
alfas

posted on 11/12/17 at 03:45 PM Reply With Quote
Polybushes....are those correct?

eBay item number:
322847773565

why those bushes have grooves on the external surface?

"Poly bushes have grease retention grooves to minimise "squeak""

makes no sense, imo, as the bush should not rotate inside the wishbone eye.

the grooves should be insiede, where the sleeve sits.

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mikeb

posted on 11/12/17 at 04:55 PM Reply With Quote
Agree, I thought the steel insert gets clamped allowing the polybush to rotate around it.
Saying that mine squeak and have huge hysteresis but only a few miles on the clock so hoping they will loosen up.

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fregis

posted on 11/12/17 at 05:54 PM Reply With Quote
maybe grooves are also in inear side.

i glue polibushes, because they rotated in housing..... housing size what should be
But i dont like my polibushes, they to soft, quality poor... buy from ebay


[Edited on 11/12/17 by fregis]





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alfas

posted on 11/12/17 at 08:29 PM Reply With Quote
so common conclusion about those bushes with external grooves: they could be called "a total mis-construction"

[Edited on 11/12/17 by alfas]

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craigdiver

posted on 11/12/17 at 10:26 PM Reply With Quote
I made the mistake of buying a set similar to those (but in black). They turned out to be far too stiff and after advice from god himself (Matt @ Procomp) I swapped for softer ones and were much easier to work with.





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CosKev3

posted on 12/12/17 at 11:58 AM Reply With Quote
Bit of a worry that when the manufacturer of a part doesn't understand how it works
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alfas

posted on 21/12/17 at 07:56 PM Reply With Quote
i sent him several quesions about this issue...he is insisting that he is right that the bushes MUST rotate inside the wisbone...i tried to explain him the correct working principle several times, incl. several links to other webpages.....conclusion: he insists on his opinion .
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alfas

posted on 12/1/18 at 12:44 PM Reply With Quote
as they havent been expensive i purchased a set from this company Polytorq

shipping took 1 months thanks to ebay´s famous GSP (global shipping program)...and here comes the facts:

the inner sleeves are made of mild steel, with a rough, unmachined surface
the sleeve has an OD of 18mm and the hole in the bushes are 17.5mm

means extrem tight fit, plus rough surface...those bushes will never pivot over the sleeve, the complete assembly will rotate inside the wishbone eye....a total mis-construction.

the supplier was replying:
This is our preferred design as tested with other users. The grade is 95 shore A. There are grease retention grooves on the outside of the bush. It is deliberately tight on the sleeve. The principle is that the sleeve is clamped rigid between the pivot points. With the forces of suspension this allows the poly to rotate either on the sleeve or inside the arm location and by so doing reducing the chance of poly squeak. Regards. Mike

my reply:
a polybush, whatever brand, MUST rotate/pivot on the sleeve...never the bush inside the wishbone.
any design which does not follow this principle has been wrongly designed.

why the above described principle is followed by ALL other brands of polybushes?

why the above described principle is written in all books about suspension?

why the above described principle is described in every web-forum about suspension?

why all other brands are using a sleeve which has a polished / smooth surface and yours have a rough / matt surface?

suely not because ALL the others are wrong!!


their reply:

I have been involved in the manufacture of polyurethane bushes since their concept in 1990. There are many schools of thought on how they should perform

I do not wish to enter into a technical debate with you

Please return for a full refund including the cost of postage

Good luck with your project. These bushes are used on OEM vehicles. We are happy with our product

They are happy with our product

They have a lifetime guarantee against failure


my reaction:
those bushes went straight into the bin!!

[Edited on 12/1/18 by alfas]

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Mr Whippy

posted on 12/1/18 at 12:56 PM Reply With Quote
quote:
my reaction:
those bushes went straight into the bin!!


pity as he was about to give you a full refund including the cost of postage... kind of shot yourself in the foot there

[Edited on 12/1/18 by Mr Whippy]

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Camber Dave

posted on 12/1/18 at 02:11 PM Reply With Quote
Quote
" These bushes are used on OEM vehicles. We are happy with our product"

Polytorqe may supply bushes to be used as he described in a cast iron component but our 'thinwall' wishbone eyes make them totally unusable.

I only use Superflex. All come with Stainless sleeves, grease and some bushes including ARB mounts have a grease retaining cross hatch INSIDE the bush.

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rusty nuts

posted on 12/1/18 at 06:59 PM Reply With Quote
I can't help it wonder how many wishbone failures that used to be a regular problem on locost suspension was down to incorrect poly bushes and crush tubes?
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