rash
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| posted on 10/2/04 at 09:35 PM |
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panhard rod
was thinking of putting a double set " two 45 degree bends" in the rod instead of running it at an angle across the rear of the de-dion
anyone have any thoughts???
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craig1410
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| posted on 10/2/04 at 10:21 PM |
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Rash,
I'm not sure exactly what you mean. Can you do a quick doodle and post it here or even just explain it a bit more.
Cheers,
Craig.
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Mark Allanson
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| posted on 10/2/04 at 10:34 PM |
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I think an 'S' shaped panhard rod would be given the ability to flex in both tension and compression, giving you unpredictable handling
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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GO
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| posted on 11/2/04 at 11:57 AM |
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I dont think a very slight flex in the rod will make a noticeable difference to the handling.
Dont forget a panhard rod makes the axle describe a slight arc as it moves up and down anyway, I dont think the effect will be any more noticeable
than that. Generally the axle will want to follow the path of least resistance which will be for the panhard rod to rotate on its pivots.
All depends on how much flex it adds to the rod.
However, I'm not sure why you'd want to do it anyway? Is it a space issue?
Although I think the effects would be minor, it is an unknown and there is a risk that it might cause problems as Mark suggests so I'd avoid it
if you can.
Suspension, brakes and steering are not areas you want an unknown!!
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ed_crouch
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| posted on 11/2/04 at 12:39 PM |
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an alternative to the panhard rod is to fit a watts linkage.
It works like this:
the chassis has a mounting stud on it on each side, not unlike that for the chassis end of the panhard rod, but there is one on each side. Attach a
rod to each, such that the rods are long enough to meet in the midle behind the diff. Attach a 3rd link between the two ends, and drill a hole half
way along the 3rd link. Pivot it to the axle/diff/DeDion beam.
This system totally eliminates sideways movement of the axle. More complex and heavier though.
Ed.
If that makes no sense, wait a coupls fo days, them have a look at my website under locost files. I will put a piccy in.
Link is below
I-iii-iii-iii-ts ME!
Hurrah.
www.wings-and-wheels.net
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stephen_gusterson
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| posted on 11/2/04 at 12:40 PM |
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I woulda thought ANY flex is BAD.
The panhard rod is the only thing keeping the axle from flying out of the side of the car during cornering.
Bends in the rod will be like a built in spring
atb
steve
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madforfishing
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| posted on 11/2/04 at 06:14 PM |
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I agree with Steve G.
The forces during cornering are going to make the Panhard straighten out during one direction and compress in the other.
Any extra flex you induce will want to throw the axle one way or another and possibly make your Rose Joints or Metalastic bushes suffer.
Have you looked at attaching the Panhard in another place or shortening it up ?
Just advice, by the way, not trying to preach or be a smart a**
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madforfishing
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| posted on 11/2/04 at 06:18 PM |
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I agree with Steve G.
The forces during cornering are going to make the Panhard straighten out during one direction and compress in the other.
Any extra flex you induce will want to throw the axle one way or another and possibly make your Rose Joints or Metalastic bushes suffer.
Have you looked at attaching the Panhard in another place or shortening it up ?
Just advice, by the way, not trying to preach or be a smart a**
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GO
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| posted on 11/2/04 at 06:23 PM |
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Still gonna be better than a 4-link though??
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Mark Allanson
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| posted on 11/2/04 at 08:02 PM |
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The panhard rod in my car, and I assume all other book chassis's is set at an angle. As the axle rises, the panhard will follow an arc centred at
the chassis bracket and the radius of the length of the rod. With this rise, the axle has a deflection to the nearside of the car which is amplified
by the at rest angle of the rod. I raised the chassis bracket to make the rod more horizontal to minimise the effect. It may be me being paranoid, but
doing it makes me feel happier about the design
 
Rescued attachment Panhard Bracket2.jpg
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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stephen_gusterson
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| posted on 11/2/04 at 11:00 PM |
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if you work out the 'effective length change' of the rod as it scribes thro the suspension arc, you will find its suprisingly tiny. Its
likely to be taken up by the bushes or a small sideways axle deflection.
for a 1000 mm rod scribing a 75mm movement at the end, the length change is 2.8mm
The same effect occurs for front suspension wishbones - as the wheel goes up, it will tend to move inwards by a tiny amount as a whole.
making the rod level at rest like mark has will centre the movement change when static.
draw it out on some scrap wallpaper and see for yourself what the change is
or use the calculator at
http://www.1728.com/pythgorn.htm
atb
steve
[Edited on 11/2/04 by stephen_gusterson]
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