I seem to remember reading somewhere that the rear suspension bushes on a live axle set up have to be the rubber type, due to the fact that when going round a corner if I use the solid nylon type bush , it won't allow the suspention to roll,as it were.
As i have already fitted my nylon type ones from lolocost, have I cocked up?

you haven't cocked up. the poly bushes will be better than rubber ones..

You need bushes with some give in them, eg. rubber or polyurethane. Nylon is too hard and brittle - OK for a bearing or bush which is subject to pure rotation, but not one which needs to compress, too.

Cheers,

Eddy

I was happy till I got the last post !
50 -50!
So come on chaps, are they ok?
Does anyone have the poly type bushes fitted to an on the road, live axle car?

Sorry ,just properly read the other post.
The bushes that I have are from Lolocost.
what are the made of?
Anyone have them on their car?

Paul, Eddy is right (Lancs lads always are!)

Nylon - bad. PolyU - good

I suspect they may be poly though....are they "rubbery" or fairly hard.....poke 'em with something pointy...do they spring back or stay dinted?

Alan,

And if you poke em and they don't spring back then they're nylon??

Probably.

What it does show you is that they are hard and have no give.....in use the slight twist generated has to be reacted somewhere...with stiff bushes you will ...

a) wear them out quickly..or

b) twist/strain/fatigue the brackets at one end or the other...or

c) twist/strain/fatigue the arms..or

d) some combination of these things

It may be that they are compliant, just very stiff...can you grip a flange in the vice, and does it give and restore? or just act hard and brittle?

Also colour is clue, Nylon is usually white, sometimes black...what colour are yours?

You could always contact the supplier I guess...:-)

I've just picked up my kit from Luego, got a load of stuff all at once, bushes being some of the items.

They are supposed to be poly, but I had a good look at them last night, and they seemed blo0dy hard to me! They felt pretty plasticky to my inexperienced hands. I know polys are supposed to be a lot firmer than traditional rubber bushes but these seemed quite a bit firmer than I was expecting ;p. I'm going IRS so I don't think there shouldn't be the same twisting forces as live axle?

Oh yeah, and they're black.

[Edited on 1/4/2003 by GO]

The thing with polyU is that it comes in many different hardness grades...

If Luego say it's PolyU then I would believe them and assume it is just a harder grade.

Ah..IRS you say...is that upper and lower wishbone style?...if so I don't think there are any twisting forces on the bushes, just pure rotation....so the bushes can be very hard as no compliance is needed....

Does that help?...or make it worse?...:-)

Cheers Alan, that helps a lot.

Yes, IRS design is of upper and lower wishbone style so all forces should only be rotational (providing everythings square!) which is what I was thinking, just needed someone to confirm it for me!

Thanks again.

quote:

---

Originally posted by Alan B
Paul, Eddy is right (Lancs lads always are!)

Nylon - bad. PolyU - good

I suspect they may be poly though....are they "rubbery" or fairly hard.....poke 'em with something pointy...do they spring back or stay dinted?

---

quote:

---

Originally posted by Viper
.....Didn't i say poly bushes...i doubt any manufacturer is going to supply nylon for this application.............

---

Alan, I didn't think you were looking for an argument, sorry if that was the impression i gave, I understand that Lolocost have, shall we say, not the best of reputations, but i would not have thought they were that daft.
I also believe that a lot of people on here would not be able to tell the difference between nylon and a poly bush with a high shore rating, i know i wouldn't if i hadn't machined both in the past..

Hey Viper, no problem...I think we were both saying the same thing anyway.....sometimes threads can wander and points can be missed....I know I do it a lot....:-)

I agree about the machining...damn I hate poly...:-(

Hi Alan
the bushes that I have Are black in colour (color to you Alan!)
They have machining marks on then & are v. hard.
If I poke them with something sharp, there is no disernable give.
Is there any way of identifing what they are made of?

Hi Paul,

Colour is fine.....I am from Preston after all....:-)
As I would hope and Viper would expect they should be just very hard poly.....but, it is worth a call to Lolo just to ask the question.
No doubt there will be ways do indentify the material, but as the poly becomes harder it gets more similar to Nylon unfortuneately.....can you squeeze the bush in a vice at all...if there was any give it would show..or you could fit one into your link then bolt it up to your frame and see how it resists (or allows) any twist....

A really good sharp close up photo of the bushing would help too....

It's unlikely to be Nylon, as it's not that suitable for bushes. A far superior product would be one of the acetal family, which usually come in black and natural. They are rock hard, but very slippery. If it's Nylon, you should easily be able to nick it with a knife, but if it's acetal, it will resist a sharp knife.

Rorty, the trouble is Delrin (acetal) wouldn't be much good either...this is not a rotation/plain bush type application but rather one with some twist too...so really a compliant material like rubber or polyu is required...as I see it anyway....

The thread gets confusing because 2 different applications are being discussed..

I agree with your comments BTW...I love Delrin...

I think (hope) the material is PU, as it will allow a degree of compliance. A phone call to Luego could put a lid on this.

Ah...you see the problem with two threads in one......

The suspected Nylon (or something hard) was a live axle Lolocost issue.

The Luego question was about conventional (rear) double wishbones which would be fine with rotational only bushes.

I think everyone is in agreement...it's just about answering the right question I guess....:-)

Does anyone know a brain surgeon?.....my brain hurts!
(Python humour)