I've got really thick hair, and because of the style of Riding I do sometimes it's not traditional for me to tuck it into the helmet. My Charles Owen works well for both! Just make sure your bun is low enough
I have a Charles owen and very thick hair. It doesn't fit under my helmet when I try that. I put it in a low bun and hairnet and it usually works just fine. Sometimes if the bun is a little high the helmet will tilt downwards, but as long as I put the bun as low as I can get it, the helmet sits just fine.