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poly bushes how do they work what moves
bart - 28/5/18 at 08:18 AM

ok i'm confused

poly bushes can someone explain how they work tolerances for fit ect.

I have read contrasting views on fit and what part moves


1) are they a direct replacement for rubber bushes ie: its the rubber / poly that twists

or like nylon bushes the inner tube rotates as in a bearing.


a) should the outer diameter be a tight fit in the suspension arm tube

b) should the inner diameter grip the crush tube or be a rotating bearing fit .


c) should the crush tube be smaller than the combined width of tube + bush sides ( top hats ) or longer allowing for a bearing fit


i know you clever people have the answers


adithorp - 28/5/18 at 08:53 AM

The bush is tight in the wishbone.
The crush tube is tight in the bracket
The bush rotates on the crush tube
The crush tube should be the same length as the bracket.
The total width of the bushes in the wishbone should be slightly less than the length of the crush tube.

Crush tube... the clue is in the name.

[Edited on 28/5/18 by adithorp]


CosKev3 - 28/5/18 at 09:41 AM

As above

One thing to be aware of if you are making new wishbones is the thickness of the steel used in the bush holding tube.
I had issues finding bushes that worked correctly due to the steel used being on the minimum thickness advertised by the seller, so the poly bushes were loose in the tube,so they then spun in the tube rather than rotating around the crush tube.