poly bushes, whats ppls thoughts?

[robrabbit]

my mk1 already has tien coilovers, and has developed a knock on the rear suspension so i was considering an upgrade to polybushes, what are peoples experiences with these?
fitting and driving wise?

[pmanson]

We've got a knocking sound from the right rear o/s

It's almost as if the suspension bottos out. It's just passed an MOT with no problems so i'm going to jack it up and have a look.

What should I be looking out for in terms of wear on bushes?

[Herman Toothrot]

Its very unlikely worn bushes will cause knocking from the suspension. The most likely candidate is a loose bolt on the strut or topmount or the damper has failed.

I replaced my 10 year old front bushes for the Orange no grease Polybushes and to be honest I think there is little difference to before, they are maybe a bit more supple, the old bushes go solid with age. I ended up leaving my rears as I didn't think it was worth the bother (stock & Orange Poly bushes work by NOT allowing any "slip" movement but actually themselves twist to allow movement). The purple ones you grease maybe a different story as they actually allow the components to move against the bush, so I imagine allow a lot "easier" suspension movement. Down side its more maintainance as you have to grease them and as they actully have movemnent against them wear out quicker, (according to the other manufacturer). Below is copied from the ownersclub, as can be seen they way they work can be argued either way, basically each manufacturer says theirs are best etc, you have to decide for yourself.

rjwilson on the oc - hope you don't mind said:

There are two manufacturers with kits for the 5 (as far as i have found) SuperPro and Polybush. Polybush are the red/orange ones, SuperPro are the purple ones. Now unfortunately the thread with the bush comparison and discussion involving there suppliers is now gone (it was part of my suspension upgrade thread). The thread listed the pros and cons for both with testimonies from both sides. The end result was SuperPro being deemed (albeit some no liking) the better choice, reasons being to do with how the bush stresses the suspension components during travel. Whereas Polybush is fixed and the bushtries to turn but struggles causing excessive wear, Superpro does not as it has greased inner metal tube. The other side of this arguement is that the Superpros need to be greased occasionally (maybe MOT time just to keep it regular) where as the Polybush ones dont but they are not as good wear wise. The rotation of the inner tube is pretty cruicial in the bushes function (apparently - this was phil's blurp on last thread) and with it being fixed in polybush ones its not doing that good job and wears more. Take into account more wear means shorter life but these are polyurethane it will still be WAY more than OEM rubber ones.
So then whats better a bit of greasing or new bushes every so often?

Edited by Herman Toothrot on Monday 17th March 13:15

[skinny]

you shouldn't have to regrease the bushes - they are normally internally patterned in such a way to retain the grease, and there's no significant heat to melt the grease so that it all falls out.

[Herman Toothrot]

skinny said:

you shouldn't have to regrease the bushes - they are normally internally patterned in such a way to retain the grease, and there's no significant heat to melt the grease so that it all falls out.

I've only seen the purple ones for an MR2 anti roll bar and they were smooth on all surfaces. MX5 ones may well be different, I don't know i've not seen them. Loads of people must have polybushed their cars and some must have gone for the purple greased ones, be good if they'd comment.