19 replies to this topic

[mattista]

thanks guys , so opinions are mixed really , so like them , so dont , the guys that like them what do you recon are the best ones to get for a fair price ?

[Ju Boy!]

Depends where you use it. In some places (that people tend to use it on Minis) it's the very worst material you could choose. Motor manufacturers continue to choose rubber, despite it being more expensive, heavier, harder to work with and having a limited shelf life compared with poly and there's a reason for that.

Thats because rubber it softer then Polyurethane, therefore giving a softer ride!? i cant think of anywhere on a mini that rubber would be a better option when looking at it from a handling point of view. other then purchasing a good set of tyres its the best thing you can do to improve your cars handling. and the harder the better!

[Dan]

That's simply not true. Both rubber and poly can be produced in a huge range of hardness grades, the possible ranges of which overlap considerably between the two materials. In many cases a harder than standard grade of rubber will be far superior to poly. There is far more to consider than just that in the choice of material for any application. Bottom arm bushes for example are simply not a good place to use poly. Poly is plastic, not elastic. Bottom arm bushes by their very nature need to be elastic, it's part of the design of the suspension system. Poly used in bottom arms plastically deforms very rapidly, within a few short months the bushes are fixed in the shape the bottom arm is holding them to and from then on are doing nothing to control the position of the arm. Poly doesn't usually absorb vibration unles it's a very soft grade indeed. Rather it transfers shock loading directly, making it a poor choice for the inside of a tie rod and often causing the end of the tie rod to snap off when used there. For the outside of the tie rod though, it's far more suitable and provides good control. There was in the past a company making poly replacement cone springs, quite a ridiculous use of the material. Plastic springs become solid much faster than rubber ones.

[Ju Boy!]

im simply talking about it from a handling point of view. you cant even reliably begin to set a cars chassis/ suspension geometry for maximum performance with standard grade rubber. all rubber bushes should be removed and replaced with Polyurethane or something harder. because as you add any external force to the suspension e.g. driving the car, rubber will begin to deform therefore changing suspension geometry.

[Mini Mad Drakeley]

i went to north west minis, didnt really see any others on the internet so i bought their full car kit and if im bein fussy they didnt include exhaust mounts or engine mounts lmao but the ones north west minis do are quite flexible, almost like a very toughened rubber and i dont see any reason why the wouldnt absorb the vibrations, the only reason i think they would is because i hit a few with a hammer but the full car set cost me £70 and im glad i bought it