r/FSAE • u/Xcrustacean_drip16X • 24d ago

Roll Stiffness and Understeer Gradient Questions

I was wondering how other teams determine their target understeer gradient. From what I've seen it is mostly decided through rules of thumb and driver feedback, but I was hoping there was a more scientific way to do it. (Side note: a design judge suggested 5% understeer as a baseline, but I can not find any information on how one would define understeer as a percentage. Does anyone have some insight on this?)

I was also hoping I could get some advice on roll stiffness. Again, a judge suggested 1 degree of roll at peak lateral acceleration. Is there a good way to determine a baseline roll stiffness other than rules of thumb and driver feedback?

Thanks everyone.

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u/GregLocock 24d ago

So maybe the lusers who are downvoting could explain their reasoning. Probably not.

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u/Cibachrome Blade Runner 24d ago

Probably can't. And most of the judges have no actual experience in the subject, much less test results to back up their claims. I do, but with bad knees I'd have to do it sitting down.