It is my understanding that you don't want to wear anything thicker than one of those thin, skull cap type hats underneath the helmet. Anything thick like a fleece or knit cap/toque can compromise the fit and thereby reduce the level of protection.
I have always worn a bandana tied around my noodle. (...As old as I am, Im sure ppl think Im covering up bald,) but that's not it. I do this to help with sweat absorption/dispersal, it keeps it from soaking the helmet liner and running down my face, into my goggles etc. It's very thin and doesn't effect the fit of my helmet as far as I can tell.
You're only Young Once,.. but you can be Immature FOREVER!
2012/13 (48) days out!
2013/14 (31) days out!