Radius arm polyurathane bushings

[kram350kram]

Thinking of using polyurathane radius arm bushings. Anyone have an experience with them? Have new stock rubber pieces in place now. They seem pretty pliable and flex a lot.   

[BDA]

I don't have any experience with poly radius arm bushes but our own Serge Sleurs posted a video showing how to make nice radius arm pivots with ball joints. I thought it was a good idea and better than even poly bushes if you want minimal flex. If you or a friend can weld, and do simple fabrication, they are probably even less expensive than Lotus Supplies' poly bushes (the only place I know where to get them). https://www.youtube.com/watch?v=0Os40ns8NiI

[EuropaTC]

Hi,
I can't help on the experience side but I'll be interested to hear anyone else who's gone this route.  The ones on my car are quite old now and I wonder how much more they flex from when they were new. As you say, there's a lot of rubber there to move about.
Brian

[Bainford]

I'm interested in this as well. I replaced my radius arm mounts/bushings a few years ago, and thought they exhibited quite a lot of movement. There is opportunity to improve rear suspension precision here, though potentially at the expense of harshness.

[Pfreen]

From what I know, they will be more precise than the oem bushings for racing.   However, they are prone to squeak, and they don't last.  They require silicone grease. I went through this on my Tiger and decided to go the oem route.

Let us know how they work if you dive in.

[BDA]

I'm not disputing you because I have no experience with spherical ball joints on a road car but I wonder what kind of spherical ball joints you used. They are available in PTFE lined which would not require lube (and should not be lubed because it would attract and retain grit). I use PTFE lined rod ends on my rear suspension and they don't squeak so I wouldn't think that a similar ball joint would squeak either.

As for the life expectancy of them, I don't know.

[jbcollier]

Nomenclature can be confusing on the Europa rear suspension.

The radius arms are at the long, sheet-steel- fabricated arms that hold the rear upright and attach to the chassis by flexible mounts.  These mounts are available in polyurethane.  The same mounts are also used in the early Esprits and Lotus Seven S4s.  They will not squeak as there are no moving parts, just flection.

The lower links run from the transaxle to the uprights.  These use rubber bushings from MGB shock arm to kingpin joint.  They are also available in polyurethane and need to be properly lubicated as the bushings do move on a SS pivot.  Copper anti seize is one recommended lubricant.  Water will wash the lubricant away and they will start squeaking but it is annoying, not detrimental.

One other factor to consider is that there is often an increase NVH when switching to polyurethane.  Just something to keep in mind.