Originally Posted by
Sy Reene
No doubt MIPS is likely safer. I will though say I have wondered if there's any level of negation of the improved safety if one wears a skull cap, beanie, balaclava, etc underneath.
I would expect just the opposite. Mips basically allows the head to rotate within the helmet, reducing rotational forces in a crash. If anything, I would think an extra layer between head and helmet would simply be more of the same, albeit not in a controlled fashion. Consider - they don't make specific recommendations for hair styles, and I would expect a full head of hair to act somewhat like a cap relative to a bald head.
Seems like it'd be an easy enough hypothesis to test. Maybe one of the helmet manufacturers or independent labs will do that. I rarely ride without a cycling cap under my helmet, so I'd be pretty interested in an actual test.
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