Helmets need to be snug, and I've found that most other riders I run into are wearing helmets that are at least a size too big for them. Arai (and other manufacturers too, I'd assume) offer different sized cheekpads to customize fit. Try and find someplace that carries many different brands, and that has someone on staff who understands helmet sizing.
And forget Shoei, it sounds like your head isn't round, so they're never going to fit right.
Chiming in here...my head is definitely not round, but the Shoei Multitec fits me better than other brands I tried. So I wouldn't rule out Shoei without sampling first...
Originally Posted by 05Train
Oh absolutely, try everything and buy what's comfortable. I'd love to be able to wear a Multitech or Neotech, but my head's just too damn long. I have an Arai head, and that's just all there is to it.
Originally Posted by flyrider