Ran into this article on the miata forum. Sharing the info here.

I had never read about wheel flex before so I found this interesting.


http://www.speedelement.com/images/h...tion_test1.jpg
http://www.speedelement.com/images/h...tion_test2.jpg
http://www.speedelement.com/images/h...tion_test3.jpg
http://www.speedelement.com/images/h...tion_test4.jpg
http://www.speedelement.com/images/h...tion_test5.jpg

 

So the moral of the story is don't "custom lighten" your wheels.

The story makes complete sence, but it sounds like they had the wheel lightened to show this specific result. I wonder if not using "anti slip" paint was part of the lightening process

They make a good point at the end of the article that rigidity is more related to design, than construction (cast vs forged). I have bent more lightweight forged wheels than I have heavier cast wheels.