interestedparty
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| posted on 10/9/02 at 05:38 PM |
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Strange and interesting front suspension
I found this image on a link Unclefista posted on the engine board-
http://www.softarc.com/~ron/locost/leftfront.jpg
I notice the use of rod ends instead of balljoints on the top wishbone, and maybe on the bottom wishbone as well, can't be sure. There doesn't seem
to be a way of emailing the website owner to ask him for more info. Also, to ask him how long the rodends last used in this way. If it is a viable
solution then it might be a good way of adapting other front uprights to work with twin wishbones. Any comments?
John
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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johnston
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| posted on 10/9/02 at 08:07 PM |
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rose joints instead of bj's or bushes are a common site on rally cars all the works cars use them for everything
anti roll bar links track rod ends, wishbone moints bj's the lot
all you have to do is buy 1 that is rated high enough for the load its gonna take trouble is the higher the load the biggr it gets or if you want it
to stay small it gets rather expensive
get down to your next major rally (check motorsport news) and look at the grpa escys and imprezzas best at the service areas
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UncleFista
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| posted on 10/9/02 at 08:55 PM |
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I've not got the book to hand but isn't there a picture of a Westie with rose-jointed suspension in there somewhere ?
Prolly on someones site, just ignore me, its around that time...
Tony Bond / UncleFista
Love is like a snowmobile, speeding across the frozen tundra.
Which suddenly flips, pinning you underneath.
At night the ice-weasels come...
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fastenuff
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| posted on 11/9/02 at 07:01 PM |
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When you go and take a look at the prb site, you'll see their set up also incorporates rosejoints
Ingmar
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stevedenbigh
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 posted on 12/9/02 at 02:06 PM |
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When at Uni i worked on the suspension design of a Formula Student/SAE racing car (see www.formulastudent.com). Part of my job was to select suitable
bearings for the track rods and suspension mounts. When selecting spherical bearings the following must be considered:
1 Radial Load, the load at which the bearing will fail if pulled radially ie at right angles to the bolt that passes through it
2 Axial load the load at ehich the bolt will fail when it is loaded along the axis of the bolt that passes through it. This is normally only 10 or 20%
of the radial load. Not all of teh joints in the suspension will be jubjected to large (if any) axial loading, but one that certainly will be in a
Locost is the one thet connects the lower front wishbone to the upright. The load on this will be very high as it is not only the supporting the
weight of that corner of the car, but also due to the force caused when the wheel encounters a bump and is forced upward whilst the spring/damper try
to resist this movement. When Costin and Phipps wrote their book on chassis design they estmated this load was three times the normal wheel loading,
whilst Williams F1 use a figure of 8 to 10 times the normal loading. On top of this you should use a safety factor, a factor of 4 is commonly used by
normal engineers, whilst racers use a factor of 2
3Amount of angular rotation of the bearing-make sure it does not rotate beyond its specified amount during full droop to full bump, through all
positions of steering angle and camber/caster adjustment
4 If you really must use rod ends, make sure that they are very high qualiity and that the threaded postion of them can take the bending and shear
laoding they are subjected to. Formula Student judges HATE rod ends, especially Carroll Smith (whose books should be read by those buliding locosts).
A much better alternative is staking bearings. Aurora Bearings were handing out a reprint from RACETECH magazine on this subject at thsi years
Autosport show, so try contacting them to get a copy, and get there catlaogue which is very helpful too
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MustangSix
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| posted on 12/9/02 at 02:22 PM |
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Aside from strength, an issue in daily usage is that most rod ends are not protected from the elements by a boot. They suffer from water, salt, and
dirt intrusion and will corrode or deteriorate from those. Unlike regular tie rods or ball joints, they have a considerably shorter service life, in
my experience. On a racer this is not normally an issue (racing on salted, icy roads?  )
If subjected to use in those conditions, they should be inspected frequently and replaced whenever they exceed tolerances.
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stevedenbigh
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| posted on 12/9/02 at 03:18 PM |
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Demon Tweeks sell some boots to keep the dirt out
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