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Old 02-25-2015, 01:54 PM   #187
ZDan
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Quote:
Originally Posted by RBbugBITme View Post
Part of the problem it represents is that your jacking forces will switch from positive to negative (anti-jacking) mid-corner. No one ever wants to design that in on purpose. You either maintain a RC above ground or below and keep it there.
I don't think it's a problem. You'd never notice the difference between the roll center being 0.1" above the ground vs. 0.1" below the ground. Yeah, there will be an optimal range for RC height (highly dependent on the application), but nothing magical or bad happens when it passes through zero.

Quote:
The other issue is the wild swing in the moment arm length.
There *is* some wild movement of virtual mathematical points, but if you look at the actual loads going into the suspension mechanisms, you aren't seeing radical changes in actual physical moment arms.

I really think that the crazy curves going to +/-infinity are more indicative of localized regions where the *math* goes unstable and not an indication of actual problem areas.

I would have no qualms about testing an FR-S/BRZ at 0", -.5", -1", -1.5", -2" to see what happens. My guess is that nothing particularly weird happens at -1".
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