cross-posted from: https://sh.itjust.works/post/26471848
But they're made of the same material so it shouldn't make a difference. They also didn't hit the foam with a hammer in the study, by the way.
To the point of FortNine's accuracy in the figures, Ryan says himself that he's not aware of a proper study performed on used motorcycle helmets and he has his own personal formula, so... reasoned but not a source of scientific truth.