polyurethane suspension bushes

[Ricky]

Hi everyone I just wanted to know if it is possible to make your own suspension bushes without using polyurethane could it be done and if so what material could you use to make them

[Talonmotorsport]

You can use a nylon type material for the bushes but it would only give you a pivot, it would transfer every jolt straight through the chassis. It could even lead to material failure around the suspension brackets. If your feeling very sadistic you could use rose joints on the wishbones at the chassis end of the bones. Then it will feel like the chassis has been hit with a hammer every time the suspension moves.

[robo]

According to a mate of mine that has made one offs in the stuff the polyurethene has to be left in liquid nitrogen to freeze and then turned quickly before it warms up. It is then no different than turning hard plastic.

Bob

[Ricky]

Thanks Talon I see what you saying so guess hard plastic is not a good idea its just that polyurethane is a mission to turn so I heard so anyway thanks guys?

[alga]

PU bars are not cheap either. A mate of mine had his bushes turned out of PU, and the cost came close to the price of a nice set from SSC.

[spud69]

Originally Posted by alga

PU bars are not cheap either. A mate of mine had his bushes turned out of PU, and the cost came close to the price of a nice set from SSC.

To be honest Albert the PU bushes are relatively cheap it is the cost of the s/s crush tubes that are the expensive part. Due to the wall thickness for the strength they need to be drilled out and then turned from solid rod which is not cheap to buy and takes time. I've heard of PTFE rod (quite cheap and easy to turn) being used for bushes but in my belief i think this would certainly wear quite quickly. It is extremely low friction but easily damaged / work to.

As Phil says the PU removes all the road vibration from the suspension and makes for a very smooth ride. Some people say the PU wears and becomes sloppy after a while but i have had the same set in a car for 3 years and 12k miles and are still fine.

Regards.....AndyH

[Wynand]

Ricky, why not just buy them from Midas? Give them the ID and OD needed but they will probably longer than needed, but no matter.

I had bought all my 36 PU bushes (yellow ones) from a local shop at R7.05 each. No way you can make them for that price - even nylon (had made a batch but scrapped them in favour for PU) will cost you more and not to mention lathe time....

Yes, all the bushes I bought were to long and cut them back on the lathe to size and PU can be troublesome to turn.
What I did was; push a crush tube in the PU bush to just short of where you want to part off the excess - this allow for the chuck to grip properly without compressing/collapsing the bush which is a common problem with PU bush in a lathe. Set the lathe to very high speed and use parting chisel and the PU will cut easily and smoothly.

Edit: when parting off excess on lathe, the off cut side goes in the chuck with crush tube as not to damage the bush flange and part off the bush size needed with flange.

Hope this helps.

[ashbudd7]

I used UHMWPE (ultra high molecular weight polyethylene) to make mine after having a little search on here for alternative materials then searching for each of their properties on google. Cant remember any exact websites but there were a fair few and they all said it was good for bushes, and a lot of the same words were used to describe the properties of the two.
Oh and the rod only cost (my boss!) about £18 and I've got loads left over (may be good for pedal box later but again ill have a look about then too)

(quick disclaimer:I can't recommend any material as I am not a polymer expert in any way and i only did a few nights of research on this, just finally able to share something!)

[Ricky]

Thanks guys ill look into all the options and thanks wynand I think your idea will be good to