Trying to create a simple program a bit like this myself (and without the funky graphics).


suspProgram

To work out the roll center I need to know the center of the car, however this position changes when the car rolls/hits bump/droop. So for the purposes of my program where should I locate it? Between the tyres?

you'd use the centre at the height of the centre of mass of the sprung components.
Guess at about a foot up from the bottom of the chassis (or the middle of the top of the chassis)
Bob

I understand, that makes sense.

Actually centre of gravity height won't enter into geometric roll centre calculations, needed to determine roll couple....
Sorry typed without thinking
Bob

Hi without getting technical.

I wouldent worry to much about your roll center. There are more important things to take care off and chasing roll centers can mean you somtimes over look more important areas of the desighn.

cheers matt

Hmm, confused now as to where to place it. COG made sense as that is where the car is trying to roll around, however, tyre grip will try and resist the roll...

With regard to whether I should worry about roll center, I know it is a contentious subject but I can't believe it does nothing. As far as I can see, long A arm lengths should limit camber change beyond small amounts (except at extremes), and I cannot see anything good about having roll centers at the front and back moving all over the place. I doubt it would feel good at the drivers seat.

Anyway thankyou both for your opinions, I do appreciate them, even if I seem to be blindly ignoring them.

[Edited on 4/9/07 by clockwork]

Bu99er.
Just read this http://www.neohio-scca.org/comp_clinic/hand_out_reprints/Vehicle%20Dynamics2007.pdf
Now it could be complete nonsense, and it does go against most of the theory in my books... but it does make sense. Also it means there is no point whatsoever in continuing my program. What was going to be a bit of trigonometry has turned into working out force application points.
Any thoughts?

Hi clockwork, the graphics do help to understand whats hapening. Your pic shows the roll effect on the suspension, but the chassis rolling into the corner....

Bill dont talk nonsense, sometimes on a different level to most though.

[Edited on 4/9/07 by Uphill Racer]

Who's bill?
Also I note the .pdf shows a car with shorter lower arms than upper...
This is somewhat confusing.

quote:

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Originally posted by clockwork
Who's bill?
Also I note the .pdf shows a car with shorter lower arms than upper...
This is somewhat confusing.

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