Poly Bushes, are they all the same grade?

[LobbyLudd]

Have been told Poly Bushes (for front end positions, and for rear spring hanger positions) are available now apparently manufactured in slightly differing formulations of material consistency. (i.e the hardness) The description quoted was 'comfort grade' of Poly Bush' , (but could not obtain further info on who might supply these, which wasn't really much help from the 'knowledgable guy' at the time ???)

Some have said the very hard material of normal Poly Bushes gives a noticeably harsh ride compared to the original factory spec of a good quality rubber set of bushes all round

Would a 'softer' grade of 'Poly' (if in fact it is available) defeat the object of the already proven lasting qualities over the old style rubber bushes and wear out at a higher rate I wonder ?

[bmcecosse]

Speak to Jono at JLH - he will sort you out with the most suitable grade for your intended use. http://www.jlhmorrisminors.co.uk/ They are a huge improvement over rubber bushes.

[don58van]

It would be great to get the mysteries of poly bushes out in the open for us all to see and know.

This is especially important given that--as has been discussed extensively on this forum--the currently available rubber bushes are rubbish. They apparently don't have the elasticity and durability of the original items.

We also know that not all poly bushes are alike. Furthermore, arguably, poly does not have suitable characteristics to be used in some areas of the Minor's suspension.

Cheers
Don

[bmcecosse]

Where are they not suitable???

[LobbyLudd]

We also know that not all poly bushes are alike. Furthermore, arguably, poly does not have suitable characteristics to be used in some areas of the Minor's suspension.

Cheers
Don

So that sounds that some are indeed possibly softer and some are harder!
What types are best where then ? I am now keen to find out ??

Methinks will next take BMCs advice and seek more info and possible recommendations from this 'Jono' gent (sounds like he may have some good practical experience to pass on hopefully) Thanks for the contact BMCosse

[bmcecosse]

Yes - ask Jonathon - he will keep you right.

[simmitc]

There has been some very informed correspondence in Minor Matters on this subject, I think a couple of issues back. Well worth reading.

[LobbyLudd]

There has been some very informed correspondence in Minor Matters on this subject, I think a couple of issues back. Well worth reading.

Yes, just now read more fully the follow up correspondence section in the latest Minor Matters from the previous magazine issue article. This seems to be a rather hot topic with some having very differing views on the previous articles suggestion of the potential detrimental side effects in using very hard poly bushes that have practically very little or no give.

The end summary still leaves this subject rather open ended ! , and I quote from the Magazine :-
"Minor owners need to become better informed about the different types of poly bushes that are available, and the varying grades of hardness that might be suitable for different locations."

[millerman]

Perhaps the Minor Matters editor could ask Jono at JLH if he would write an article for the mag. on poly bushes

[IslipMinor]

We have 'Superflex' polyurethane bushes/pads in every possible location. They are definitely not harsh and I would recommend them without hesitation. Just make sure that they are fitted with a smear of copper grease to avoid squeaking. The original bushes were fitted dry, as recommended at the time, and did squeak a bit (15 years ago!) - since then I have added a smear of copper grease when possible, and all is quiet now! Most of the bushes are 15 years old and after nearly 50,000 miles are still as good as new.

Having said that, our 'moderns' have either BMW or Mini 'sport' suspension, so the Minor is very 'normal' to us.

[bmcecosse]

Still waiting to hear where they are NOT suitable......

[ColinChandler]

hello everyone,
I've had a set of hard blue poly bushes fitted to my Morris for about 10 years now. As everyone says, the modern rubber ones are very poor and don't last. The blue ones fitted have lasted well - installed with copper slip - but they still creak even now and the ride is very firm. Because of this, I'm part way through replacing them with these -

http://www.polybush.co.uk/shop/view/276 ... r_(Saloon)

I've gone for the "comfort" as opposed to "performance" grade and whilst I've still not finished installing them all, the ones I have, don't creak and their "feel" is very much like the rubber bushes used to be. They are supple rather than firm. Fingers crossed they give a more comfortable ride more like old times.

One last thing, the web page shows them to be red but the ones I've received are blue too just softer.

Cheers, Colin.

[LobbyLudd]

hello everyone,
I've had a set of hard blue poly bushes fitted to my Morris for about 10 years now. As everyone says, the modern rubber ones are very poor and don't last. The blue ones fitted have lasted well - installed with copper slip - but they still creak even now and the ride is very firm. Because of this, I'm part way through replacing them with these -

http://www.polybush.co.uk/shop/view/276 ... r_(Saloon)

I've gone for the "comfort" as opposed to "performance" grade and whilst I've still not finished installing them all, the ones I have, don't creak and their "feel" is very much like the rubber bushes used to be. They are supple rather than firm. Fingers crossed they give a more comfortable ride more like old times.

One last thing, the web page shows them to be red but the ones I've received are blue too just softer.

Cheers, Colin.

Thanks or sharing your practical experience on this point Colin, as this now has specifically begun to 'get at' the very question that I was seeking some explanation towards. This now explains what the 'knowledable guy' I got into brief chance conversation over a coffee must have been 'on about' when mentioning the subject of replacing poly bushes at the recent big Beaulieu event. ( Thanks whoever you were! )

It will be interesting to hear any experience of ride difference etc after the complete all round fitting of what are described as the 'comfort' grade of poly bush having actually driven with the harder grade.
It seems a softer but good quality grade is probably the way to go with the much better lasting qualities if it is in fact going towards more to replicate the original design performance intentions and 'feel' of the original factory fitted rubber ones.

[MarkyB]

In theory the colour should tell you about the Shore rating, in practice this doesn't seem to be the case.
http://en.wikipedia.org/wiki/Shore_durometer
" Durometer is one of several measures of the hardness of a material" suggests why this is the case.
I've got several poly bushes in my "to do" box and although different colours pretty similar hardness.
Anyway, top tip for the eye bolt bush is get a J2 rear spring Metalastic bush if you can, they seem to last indefinitely!

[LobbyLudd]

[quote="MarkyB"]In theory the colour should tell you about the Shore rating, in practice this doesn't seem to be the case.
http://en.wikipedia.org/wiki/Shore_durometer

Heeelp !! Now my head is throbbing

[MarkyB]

When a standard gets set, and the manufacturers use it , then it will get much easier.
Until then you need to make a judgement with the bushes in your hand.

[bmcecosse]

The colour does tell the difference in shore - but there is no agreed standard between suppliers.

[IslipMinor]

Just had a reply from 'Polybush' to say that their blue 'Comfort' bushes are 65 Shore A and the red 'Performance' bushes are 85 Shore A. They also said that the Comfort bushes are similar in ride quality to the original rubber bushes.

Will start to build a table of suppliers and specs and see what comes from it.

[bmcecosse]

Well done Richard - just what we need!

[LobbyLudd]

Just had a reply from 'Polybush' to say that their blue 'Comfort' bushes are 65 Shore A and the red 'Performance' bushes are 85 Shore A. They also said that the Comfort bushes are similar in ride quality to the original rubber bushes.

Will start to build a table of suppliers and specs and see what comes from it.

Thanks thats great! - what was originally a subject of some ' mystery' has suddenly, and now really begun to be so very much clearer and easier to make an informed choice.