zzrpowerd-locost
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 posted on 13/10/05 at 11:55 AM |
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Metalastic or poly bushes?
the book design suggests using metalastic bushes from a triumph herald. The trailing arms i have purchased have been made to suit these bushes. Will
they be ok or is there a poly bush available to suit? I dont want to alter to suit bigger bushes as they have been nicely powder coated 
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Peteff
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| posted on 13/10/05 at 12:55 PM |
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Try MNR
Here. They list these as book replacements so they might be what you are looking for.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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zzrpowerd-locost
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| posted on 13/10/05 at 01:11 PM |
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Thanks Pete. Just had a look and emailed them to make sure they will fit. Hopefully anything listed as book is a direct replacement 
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Mix
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| posted on 13/10/05 at 01:25 PM |
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Isn't there an issue with fitting poly bushes to the trailing links? Something along the lines that the links actually move in two planes which
metalastic bushes allow but poly would try to resist.
Mick
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ChrisGamlin
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| posted on 13/10/05 at 05:42 PM |
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There is a small amount of lateral movement on the live axle trailing arms but there's easily enough movement in a poly bush to accomodate that.
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clbarclay
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| posted on 13/10/05 at 06:20 PM |
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Its nylon bushes or spherical bearings which have no compliance (or too little), so are problems when it comes to making trailing arms. As Chirs says
poly bushes have some compiance. There are polybushes (labled comfort) for landrovers etc. that are very flexible/copliant in your hand.
[Edited on 13/10/05 by clbarclay]
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Rorty
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| posted on 14/10/05 at 05:03 AM |
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quote:
Originally posted by clbarclay
... spherical bearings which have no compliance (or too little), so are problems when it comes to making trailing arms.
Shoemakers!
The whole ides of spherical bearings is that they rotate in every direction.
Any of the softer compounds like rubber or polyurethane will obviously comply and any of the hard plastics such as Nylon, acetyl (Delrin), P.T.F.E
(Teflon) etc, have no, or very little, compliance.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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zzrpowerd-locost
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| posted on 14/10/05 at 10:39 AM |
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Just had an email from Marc at MNR
The "book" poly bushes he does are direct replacments for the herald metalastic bushes
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MikeR
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| posted on 14/10/05 at 11:23 AM |
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excellent - means i can look at making up my special trailing arms - book one end and spherical the other.
Combination of comfort using the origianl herald and no worries about twisting due to the rod end. If they turn out too soft i can upgrade 
me's a very happy bunny!
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Peteff
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| posted on 14/10/05 at 01:16 PM |
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special trailing arms - book one end and spherical the other
I used MK's polybush at the car end and a 12mm spherical at the other on my trailing arms and Panhard rod but my front wishbones have standard
rubber bushes. I did intend to change the front but never got round to it. That's why I was looking at MNR's bushes in case they wear out
so I won't need to remake my wishbones.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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zzrpowerd-locost
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| posted on 14/10/05 at 02:58 PM |
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well spotted pete
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clbarclay
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| posted on 14/10/05 at 08:00 PM |
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Rorty
Yes spherical will rotate in all plains but they allow very little fore/arft movement, which as I understand is needed to a degree for a live/dedion
axle to move properly in all positions.
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MikeR
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| posted on 14/10/05 at 08:06 PM |
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errm, if you have a sperical bearing on one side you're sorted. If you have sperical on both sides of hte live axle it still works perfectly
well, the problem is the ride is a little harsh.
all to be taken with the statement, "i believe", i'll tell you sometime in 2010 when i finish the car
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Peteff
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| posted on 14/10/05 at 08:22 PM |
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Yes spherical will rotate in all plains but they allow very little fore/aft movement
Which is a very good thing in relation to holding the axle in place. The axle is not supposed to move fore or aft but stay in the same plane as it
rises and falls due to the damper travel. There is a slight sideways movement due to the arc of the panhard rod which is why longer is better but this
is negligible in the case of locosts on the road and is easily absorbed by spherical, metalastic or polybushes.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Alan B
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| posted on 14/10/05 at 08:25 PM |
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quote:
Originally posted by clbarclay
Rorty
Yes spherical will rotate in all plains but they allow very little fore/arft movement, which as I understand is needed to a degree for a live/dedion
axle to move properly in all positions.
As far as I'm aware...fore and aft movement is not needed or desirable, just the abilty to accept some slight angular movement.....
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clbarclay
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| posted on 15/10/05 at 10:47 AM |
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I may be splitting hairs here (The ammount of axle movement on a locost is small). However if you either raise or lower a the axle so that trailing
arms are not perpendiculare to the chassis/axle mounting holes, then the axle can not articulate without putting some of the trailing arms under
compression and the other arms under tension. I'm sure someone on here modelled this a few months back and came to the same conclusion.
On a locost you may well be able to get away with this, but if the tensil and compression forces get to high then somethings got to give. Rubber or
poly bushes are definantly going to deflect/give first, however with a far stiffer bush like a metal sperical bearing, then it may be the chassis or
trailing arms or axle that give first.
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Peteff
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| posted on 15/10/05 at 05:09 PM |
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I just said something along these lines. The axle describes a slight arc as it moves up and down and also an arc on the panhard rod which moves it
slightly sideways which is why there needs to be some compliance in the bushes, but a spherical bearing allows movement in both the necessary planes
at the same time and will not be damaged. There should be enough play in poly or rubber bushes to allow the movement without any rapid wear giving a
good service life. As said earlier, harder materials will not stand the slight sideways deflection and will wear quicker. The axle tries to rotate
under acceleration and braking which is when the arm is under compression and tension, not when the suspension is moving up and down.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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MikeR
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| posted on 15/10/05 at 06:55 PM |
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so if we go back to my intended way of doing it, bushes at one end and rod ends the other i should have good location, good ability to twist and the
ability to defect in the arc......
quick, someone tell me i'm right or wrong before my headache gets much worse.
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zzrpowerd-locost
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| posted on 15/10/05 at 07:20 PM |
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well mike,
mnr sell trailing arms like that so there must be some method in your madness
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MikeR
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| posted on 15/10/05 at 07:41 PM |
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waahaay, might be a simple way to get some (ie save me the hassle of making them!)
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Peteff
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| posted on 15/10/05 at 08:26 PM |
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I made mine like that as I said in earlier post and they've been o.k. for 4 years.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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