>
> I'm not an expert in plastics, but the recent thread on bushings allows me
> the opportunity to show how little I know. Here goes. We all know how much
> rubber bushings give, and sometimes thats OK for rough roads. Stiffer
> suspensions want less bushing deflection and plastics are great, giving
> very little, but more than aluminum/aluminium. Nylon is good, Delrin is
> better because of its lower cold-flow. Polyurethane is about the same as
> Nylon. Teflon is awful for cold-flow. A suspension bushed with Teflon would
> very soon be sloppy. An interesting material to try would be Vespel, a
> "hard" Teflon. I could see putting different bushing materials in various
> places in the suspension, depending in what the anticipated loads would be.
> Hard materials in the A-arm pivots and soft materials in the shock-loaded
> areas, for example. Perhaps this clears things up a bit.
>
> Philip E. Barnes '71 TR6 CC61193L
> Cornell University
> Newman Laboratory of Nuclear Studies
> Ithaca, NY 14853
> 607-255-4951
> peb3@cornell.edu
>
>
Good morning,
One note of caution here. As a (former) racer the extra rigidity offered by the
harder suspension bushings is needed for control and feedback. On a street car
we have the added factor of life of the system to deal with. The more rigid the
bushing, the more high frequency components of vibrations that will be
transmitted back through to various other components. These little gems may
give a good feel to the handling but keep in mind you are changing the frequency
spectrum that is being tranmitted back through the chassis. Using bushings with
some compliance Urethane for instance will relieve many components from exposure
to vibrations they may not have been designed to withstand. Granted the design
with regards to vibration resistance of many of the components may be random but
subjecting a marginal design (IMHO all our LBCs are marginal) to increased
vibration is asking for trouble.
Your point about Vespel is right on. It is ideal for racing suspension bushings
and is appropriatly priced. I would guess a suspension kit for about any of our
LBCs (I'm talking complete kit) would run in the $1000 range. A stick of Vespel
3/4 in dia by 9-1/2 long is $155, and that's 93 pricing. Maybe it's come down.
:-)))))).
Ken
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