Bushes - Rubber / polythene

'Coz he's not a dentist...

Polyurethane bushes are stiffer so you get better location at the cost of much harshness. They are of most benefit on dreadful suspension like that fitted to the Marina^H^H^H^H^HGB but absolutely not what you want on your daily driver and pretty pointless unless rear axle location has been improved first.

Cheap computerised maths means that the predictable deformation of bushes is factored into modern suspension design and in many cases stiff poly bushes will make things worse all round by preventing desired camber and toe variations - e.g.passive steer rear axles.

I'd not fit poly bushes to anything but a track car and even then I'd only do it to solve an untweakable problem - like owning a MGB rather than a TVR or TR - rather than as a matter of course.

A

Seconded. I fitted polybushes to my Locost and they're gonna be replaced at some point, they're too harsh and unforgiving...

Must tell steveH he's got one of them now hasn't he?

Interesting. I was thinking of polybushing my Golf (MK2 GTi), but it's going to be my daily car, never a track car...

The wishbone bushes kept failing on my 205 (on new wishbones), and after this happening for the third time I decided to buy some poly bushes instead of just getting a new wishbone and having the same thing happen again. People said I would get more vibrations coming through the car, but cant say I noticed any, and there were no problems with them failing after swapping them.

Which bushes did you use? There's more than one hardness of polyurethane...

Superflex (polyurethane). They were pretty stiff compared to the standard ones.

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Do the wishbones pick up on a rubber mounted subframe or straight to the shell?

Reading

(thanks Homer) I notice they claimgood NVH performance but also that their BMW E39 kits only replace afraction of the bushes and none of the funkier ones...

A

They mount onto a subframe which is bolted directly to the floor pan.

I found

to be much cheaper, and rumour had it, just as good as Poweflex. I was only after the wishbone bushes so didnt ask what else they did.

Not only can they last longer but they're often cheaper than the rubber parts and I'm sure this is why a lot of people fit them. On many cars rubber bush wear is frequent and consequently expensive.