At 206 pounds with camelback and tools, I rotafixed at the end of a really long hill.
The cog unscrewed itself. It took me 30 seconds to screw it back. Later on that day -riding the same gear ratio as you - I did hit 150 rpms in a long downhill without any Ill effects.
That being said, the night before the incident I was in my trainer tooling around and trying to learn to skid.
I love my front brake.
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