Dantheman
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| posted on 25/1/07 at 08:37 PM |
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Roll centre height
Hi. I've done a search on here and on the net and I cant find any referance as to how you calculate roll centre height on a car. A diagram would
be much appreciated! Thanks, Danny.
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flak monkey
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| posted on 25/1/07 at 08:43 PM |
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Here you go, second hit on google:
http://www.stockcarproducts.com/pstech3.htm
Nice and simple, and saves me doing a doodle for you... 
David
Sera
http://www.motosera.com
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Dantheman
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| posted on 25/1/07 at 08:50 PM |
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Thanks! I did a search on google and all I could find was something on wkipedia that just confused me.
To the drawing board!
Danny.
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Dantheman
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| posted on 26/1/07 at 10:33 AM |
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Looking at that diagram it seems to asume that the top wishbone is angled, but what if they are parallel?
Danny.
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Doug68
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| posted on 26/1/07 at 12:17 PM |
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If the wishbones are parallel then the roll height is zero i.e. at ground level.
Where it goes from there depends upon what the lengths of the wishbones are.
Be aware what looks like a parallel arm may not actually be parallel as the true line of the geometry goes from the chassis pivot point through the
upright pivot point, which depending on the ball joint arrangement may be a decent distance from the actual end of the wishbone.
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Dantheman
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| posted on 26/1/07 at 12:50 PM |
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I know the arms are parallel, its my own design. I kept them parallel because the top wishbones are shortish so I thought if I angled them I might get
too much camber change.
So is a roll centre at ground level a good thing or not?
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Doug68
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| posted on 26/1/07 at 01:03 PM |
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There is no "perfect" place to have the roll center.
What is widely accepted is that the roll center movement (relative to the car). Through the rage of motion of the suspension is a bad thing.
Typically the roll center is lower at the front by 1" - 2" than that at the rear.
There are entire books on this subject, so i don't think my feeble explanations here will get you where you need to be.
[Edited on 26/1/07 by Doug68]
[Edited on 26/1/07 by Doug68]
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