Polyurethane vs synthetic rubber bushes
David Gammon
suspension bushes vs synthetic rubber (OEM) bushes, in particular anyone
who's had a suspension failure and has been using polyurethane bushes. A
friend has recounted a few cases where suspension components (mainly upper
wishbones) have failed where the car was fitted with poly bushes.
I've used polyurethane bushes for a number of years on a number of vehicles
without a problem, but this friend has some reliable info on vehicles which
have suffered failures - co-incidence, or are the bushes pushing the other
suspension components past their design limit, and over the edge?
Dangerous
Sasha
I have seen some cases of rear suspension trailing arm mounting points
being slowly torn away from the cars chassis after fitment of urethane
bushes. Urethane bushes also seem to put excessive wear on other
suspension components- for example I once found hairline cracks in
some front control arms that just would not have been there with the
standard soft bushes. I do not need to point out how potentialy
dangerous this is.
It seems urethane bushes come in different flavours to suit different
tastes. Without wishing to favour one manufacturer over another, the
Nolathane bushes that you mention are absolute junk. They are as hard
as a rock, and it is obvious not a lot of thought goes into their
design. I'll stick my neck out and say that most of the people who buy
them are more interested in their colour than any effects they have on
the suspension. I would not use them on a street car if they were
given to me for free.
On the other hand I have used Superpro (Fulcrum) bushes with good
results. They are compliant (ie. they have some 'give' in them), and
although stiffer than stock bushes, they don't seem as hard on
suspension as the Nolathane bushes . Perhaps they do not last as long
as Nolathane, but what I ask people is this- what would you rather
replace more often, a $5 suspension bush or a $200 control arm? The
answer seems pretty obvious to me.
IMHO
Sasha
>
>Dangerous
>
>
Jules
Now I wonder. I'm also about to redo the suspension and steering bushes in
my Torana and I was going to use nolathanes. You mentioned Superpro? can
you buy these at the same shops as the nolathanes?? Thanks in advance
Sasha <sna...@alphalink.com.au> wrote in message
news:394805a2.825954@news...
Aaron T
suspendkion parts like shocks and springs?
Jules
A car with worn bushes everywhere doesn't tend to handle very well and your
suspension components chatter a lot. I redid the rear suspension bushes in
my commodore and I couldn't believe the difference it made
Aaron T <tod...@dingoblue.net.au> wrote in message
news:394833c3$0$524$7f31...@news01.syd.optusnet.com.au...
Jon Smillie
Older Fords are famous for breaking radius rods when stiff nolathene bushes are
used.
In article <39478752$0$1251$603e...@news.adl.ihug.com.au>, "David Gammon" <dav...@iweb.net.au> writes:
|> I'm interested in anyone's experiences with polyurethane (nolathane)
|> suspension bushes vs synthetic rubber (OEM) bushes, in particular anyone
|> who's had a suspension failure and has been using polyurethane bushes. A
|> friend has recounted a few cases where suspension components (mainly upper
|> wishbones) have failed where the car was fitted with poly bushes.
|>
|> I've used polyurethane bushes for a number of years on a number of vehicles
|> without a problem, but this friend has some reliable info on vehicles which
|> have suffered failures - co-incidence, or are the bushes pushing the other
|> suspension components past their design limit, and over the edge?
|>
|> Dangerous
|>
|>
John H
>I'm interested in anyone's experiences with polyurethane (nolathane)
>suspension bushes vs synthetic rubber (OEM) bushes, in particular anyone
>who's had a suspension failure and has been using polyurethane bushes. A
>friend has recounted a few cases where suspension components (mainly upper
>wishbones) have failed where the car was fitted with poly bushes.
>
>I've used polyurethane bushes for a number of years on a number of vehicles
>without a problem, but this friend has some reliable info on vehicles which
>have suffered failures - co-incidence, or are the bushes pushing the other
>suspension components past their design limit, and over the edge?
IMHO Polyurethane is inferior to rubber in any situation where there's
angular deflection, such as wishbones. Urethane simply doesn't have
the internal shear characteristics of rubber, so there's always going
to be movement between the bushes and the wishbone eyes (or pins); and
where there's movement there's also wear.
I'd doubt that failure for any reason other than wear would be due to
the bushing material.
FWIW, anyone who can't suppress the urge to fit urethane to their
wishbones should also consider grease nipples!
--
John H
Dangerous
allows more angular displacement between the outer and inner metal sections
of the bush bonded to the rubber/poly. Most (?) upper wishbone bushes are
not an interference fit on the shaft, so no matter what the type of bush,
the bush will still freely rotate on the shaft, won't it? I understood that
the damping in the bush is purely for non axial movement/deviation of the
wishbone - any axial movement at all is allowed for by the shaft rotating in
the bush.
Of course, it's a different matter if the bush rusts on to the pin......
Dangerous
John H wrote in message ...
>David Gammon wrote:
snip
Dangerous
make it clearer what type of bush I was talking about, but I didn't
specifically mean that brand only. I haven't used Fulcrum bushes, but I've
heard about them - didn't they come in a range of 'stiffnesses' at one
stage?
Nolathane is still pretty good to use for some front sway bar mounts,
steering couplings, etc.
Dangerous
Sasha wrote in message <394805a2.825954@news>...
John H
>John, I presume that you mean that in a rubber wishbone bush, the rubber
>allows more angular displacement between the outer and inner metal sections
>of the bush bonded to the rubber/poly. Most (?) upper wishbone bushes are
>not an interference fit on the shaft, so no matter what the type of bush,
>the bush will still freely rotate on the shaft, won't it? I understood that
>the damping in the bush is purely for non axial movement/deviation of the
>wishbone - any axial movement at all is allowed for by the shaft rotating in
>the bush.
Thinking in terms of the fairly ubiquitous Harrison bush (aka
Metalastic); both the inner and outer diameters are bonded to a steel
shell. The outer is an interference fit in the wishbone and the inner
is clamped by the pin or shaft (which is usually a bolt). Thus all
the angular (axial) movement is shear movement within the rubber.
There should be absolutely no movement against either the shaft or the
wishbone.
I'm not aware of any polyurethane bushes constructed in the same way,
no doubt because urethane doesn't have the same internal shear
properties as rubber, and the bush _must_ move against wishbone or
shaft. Nor am I aware of any car manufacturer who uses urethane (it
might also be interesting to know what some of the modern chassis
engineering texts have to say on the topic).
Personally I have no qualms about using urethane where there's
insignificant axial movement, but there's no way I'll use it in
wishbones or control arms!
--
John H
JJ
arm. Not impressed.
On the other hand rubber inners on wishbones often start turning the
inner serrated end tube. Why I dont know, maybe the bolt stretches losing
its grip. I suspect road shocks will be transmitted more readily via these
firmer poly bushes?
James
"David Gammon" <dav...@iweb.net.au> wrote in message
news:39478752$0$1251$603e...@news.adl.ihug.com.au...
> I'm interested in anyone's experiences with polyurethane (nolathane)
> suspension bushes vs synthetic rubber (OEM) bushes, in particular anyone
> who's had a suspension failure and has been using polyurethane bushes. A
> friend has recounted a few cases where suspension components (mainly upper
> wishbones) have failed where the car was fitted with poly bushes.
>
> I've used polyurethane bushes for a number of years on a number of
vehicles
> without a problem, but this friend has some reliable info on vehicles
which
> have suffered failures - co-incidence, or are the bushes pushing the other
> suspension components past their design limit, and over the edge?
>
> Dangerous
>
>
Daniel Kempster
bushes on leaf springs, sway bar and links and shocks on HZ commerical vehicles?
Also Pedders use urethane bushes, (no bull).
cheers.
Sasha wrote:
> On Wed, 14 Jun 2000 23:00:17 +0930, "David Gammon"
> <dav...@iweb.net.au> wrote:
>
> >I'm interested in anyone's experiences with polyurethane (nolathane)
> >suspension bushes vs synthetic rubber (OEM) bushes, in particular anyone
> >who's had a suspension failure and has been using polyurethane bushes. A
> >friend has recounted a few cases where suspension components (mainly upper
> >wishbones) have failed where the car was fitted with poly bushes.
> >
> >I've used polyurethane bushes for a number of years on a number of vehicles
> >without a problem, but this friend has some reliable info on vehicles which
> >have suffered failures - co-incidence, or are the bushes pushing the other
> >suspension components past their design limit, and over the edge?
>
> I have seen some cases of rear suspension trailing arm mounting points
> being slowly torn away from the cars chassis after fitment of urethane
> bushes. Urethane bushes also seem to put excessive wear on other
> suspension components- for example I once found hairline cracks in
> some front control arms that just would not have been there with the
> standard soft bushes. I do not need to point out how potentialy
> dangerous this is.
>
> It seems urethane bushes come in different flavours to suit different
> tastes. Without wishing to favour one manufacturer over another, the
Julian Edgar
> no doubt because urethane doesn't have the same internal shear
> properties as rubber, and the bush _must_ move against wishbone or
> shaft. Nor am I aware of any car manufacturer who uses urethane (it
> might also be interesting to know what some of the modern chassis
> engineering texts have to say on the topic).
>
> John H
After talking with Mitsubishi suspension engineers (and others) I suggested
in my book that they should be used only with care, and preferably where
rotation did not occur.
Julian Edgar
21st Century Performance
Martin Pot
wrote:
>On Wed, 14 Jun 2000 23:00:17 +0930, "David Gammon"
><dav...@iweb.net.au> wrote:
>
>>I'm interested in anyone's experiences with polyurethane (nolathane)
>>suspension bushes vs synthetic rubber (OEM) bushes, in particular anyone
>>who's had a suspension failure and has been using polyurethane bushes. A
>>friend has recounted a few cases where suspension components (mainly upper
>>wishbones) have failed where the car was fitted with poly bushes.
>>
>>I've used polyurethane bushes for a number of years on a number of vehicles
>>without a problem, but this friend has some reliable info on vehicles which
>>have suffered failures - co-incidence, or are the bushes pushing the other
>>suspension components past their design limit, and over the edge?
After fitting nolethane bushes to the front suspension of my Datsun
1200 (sway bar mounts, radius rod mounts), I kept breaking the
linkages between the sway bar and the lower control arm (but then, I
was still using standard Datsun 1200 links with a thicker sway bar, so
maybe that was the culprit...).
After replacing the links with thicker Datsun Stanza links, I didn't
have any more problems.
Actually, what's the difference between nolethane and polyurethane?
Cheers,
Martin.
m dot t dot pot at ieee dot org
Greg Stewart
>
> Actually, what's the difference between nolethane and polyurethane?
>
> Cheers,
> Martin.
> m dot t dot pot at ieee dot org
>
As far as I know, Nolethane makes Porlurethane bushes! (sp?)
Greg.
Sasha
wrote:
>Actually, what's the difference between nolethane and polyurethane?
Nolatahne is a brand name, polyurethane is the type of material
used to actually make the bushes.
Sasha