ProjectLMP
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| posted on 22/1/04 at 02:37 AM |
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Lower ball joint question
I was planning on using spherical bearings for the outer front and rear lower suspension joints. However, I am having second thoughts because I think
that they will probably wear pretty quickly. So I was looking into using some kind of production car lower ball joints. Does anyone know of any
suitable ones that can be installed in a spherical housing, either screw in or press in?
Home of the Astronomicalcost Mid engined LMP project
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Hugh Paterson
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| posted on 22/1/04 at 02:43 AM |
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We used spherical bearings on the bottom of the Coram Lmp but found them wearing too quick and have now changed to an Audi lower bottom balljoint
that has a good spec, (used on the quattro I think) will check with Steve later in the morning and u2u the details so u can have a shuftie. He has
other alternatives that are suitable too.
Cheers
Shug.
[Edited on 22/1/04 by Hugh Paterson]
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kb58
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| posted on 22/1/04 at 04:14 AM |
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I used ball joints from a Honda Accord. Very common and obviously plenty strong. They're press-in, roughly 2" diameter, and have a 7deg
taper (not sure of that figure though.)
Spherical joints will work, but they have to be way oversized to have a good life. The Honda parts mentioned above are for the rear of my car, I use
a 5/8" spherical joint at the front bottom.
[Edited on 22/1/04 by kb58]
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timf
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| posted on 22/1/04 at 09:34 AM |
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have a look at the rear wishbone 'bush' on a toyota supra 3.0l mk2 .
not a bush as such but a cross between a bush and a spherical bearing.
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giel
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| posted on 27/1/04 at 11:12 PM |
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Can anyone please explain the difference between ball joints and spherical joints?
And is the wear that is mentioned here caused by the axial (vertical) load on the joint, while it's designed for radial loads primairely?
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Alan B
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| posted on 28/1/04 at 12:07 AM |
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In our kind of applications I'd interpret as follows.
Ball joint - sperical bearing in a housing of some sort usually with a tapered shank protruding...almost always for automotive applications...very
much an Auto part
Spherical joint - Spherical bearing in a very simple minimalistic housing (basically it's a ball in a cage) usually with a thru' bore.
Usually used with a custom machined housing...applications are varied...automotive use is near always in racing.....typically a machinery type part.
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Tudor (Ted) Miron
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| posted on 28/1/04 at 08:42 AM |
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Hugh,
Don't hide it in U2U  Make available for comunity.
What caused fast wear of rose joint? Dirt and dust that got there? I don't expect the loads to be such a problem - normal auto ball joint has
kind of plastic housing which is weak and wearing fast but it's sealed - that helps.
Thank you
Ted
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tadltd
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| posted on 28/1/04 at 11:54 AM |
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Guys,
It wasn't so much wear being the problem on the LMP - as Shug mentioned -it was more a poorly designed location on the wishbone (a legacy of the
last designer, but let's not go there...).
The ball joint is now an Audi Quattro item (also found on the Audi 90 Quattro). I sourced through Federal Mogul's 'MOOG' brand - the
part no. is: AU-BJ-3914
Federal Mogul actually have a very good online catalogue of their aftermarket parts, which easily aids
sourcing such components.
Be warned though, it flys in the face of the Locost theory - i.e. it's NOT lo-cost!Expect to pay anywhere in the region of £25-32 from a motor
factor in the UK.
However from a safety view-point, and I speak from experience, this is NOT a component that you want to take a risk with - believe me. That's
why I spec'd such a heavy duty item for such a low-weight vehicle.
We can still adjust camber through the use of rose joints at the inboard end, and rose joints on the upper wishbone. Not ideal, I know, but until I
find a better solution it won't change.
Hope this helps.
Steve.
(edited because I don't proof read before I post!)
[Edited on 28/1/04 by tadltd]
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tadltd
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| posted on 6/2/04 at 11:07 PM |
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Not sure if anyone saw this, but would imagine it'd be useful info' for some.
So I threw it back to the top of the pile!
Steve.
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ProjectLMP
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| posted on 7/2/04 at 01:46 AM |
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Thanks for the info. After some thought, due to my upright design, I am really comitted to using spherical bearings. So I decided to go with a 5/8 for
the front and 3/4 for the rear. I would have gone 3/4 all around but I don't have clearance on the front when the upright is turned. I may put
some dust seals on them. If I was doing this from scratch I would probably design the uprights to fit commercial automotive joints.
Home of the Astronomicalcost Mid engined LMP project
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tadltd
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| posted on 7/2/04 at 12:26 PM |
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We used spherical bearings originally, but changed to the commercial ball joint recently. It may be that our design allows us to do that more easily,
though.
Steve.
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rontyler
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| posted on 12/2/04 at 03:35 PM |
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Yesterday a customer brought over a lower ball joint from the front of an early VW Golf ('85 ish). It looks like a great canidate for a BEC or
other lightweight car. They cost less than $20 and, from my understanding, indestructible (in the Golf platform). Additionally they are VERY
lightweight.. I didn't have an opportuninty to weigh it, but I'd guess its under 1/2 pound whereas the generic Chevrolet bj (w/holder) is in
the 1 1/2 to 2 lb range. The Golf bj is also MUCH smaller on the outboard end which would allow for smaller scrub radius and/or KP angles. The picture
is deceiving... it really is tiny compared to the "typical" bj.
 
Rescued attachment vwgolfLBJ.jpg
Regards, Ron Tyler
"Nothing is ever accomplished by a reasonable man."
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tadltd
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| posted on 13/2/04 at 02:23 PM |
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The problem with that ball joint is that it'll need a bolt through the upright to clamp it - unless you use the original upright you're
going to run into a big headache.
The ball joint we use was chosen for the following reasons:
- It was a 'bolt-on' design (like the Golf one)
- It had a threaded end to secure it in the upright, therefore only a tapered hole was required
- It was commercially available
- It is strong (from Audi Quattro)
- It is relatively light
- It has been through a sh!t load of development!
Have a look at Federal Mogul's web-site (the link's posted earlier in this thread), they picture a load of different types of ball joint
and you can pretty much pick and choose which one is most suitable for your application.
Steve.
edited to add last 'list' item
[Edited on 13/2/04 by tadltd]
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GTAddict
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| posted on 13/2/04 at 07:39 PM |
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Couldn't put a direct link up to the page you mmight be reffering to, could you? A comparison page full of balljoints/bearings would be very
useful. (I've crawled over the Moog pages, but can't find much useful. I'm guessing it is hidden.)
Ta,
Mark.
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tadltd
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| posted on 14/2/04 at 11:33 PM |
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Try this:
Federal Mogul (click it!)
Then click on 'electronic catalogue' - once this loads up, look under 'chassis'
All I did was trawl through all the makes and models to find parts that I thought would be suitable. You need to specify the vehicle to get access to
the pic's. It's a bit of 'leg' work, but your local motor factors ain't gonna allow you to do that!
ENJOY!
Steve.
edited to add the last paragraph
[Edited on 14/2/04 by tadltd]
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GTAddict
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| posted on 15/2/04 at 06:24 PM |
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Good stuff. I was missing the 'catalogue' bit of the puzzle.
Thank you!
Mark.
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