Oh I don't know-the huge indentation on my forehead helps divert any rivulets of sweat away from my eyes. A bit like a BO Suez Canal I suppose. You don't get that with Cinelli hats, do you?
It's only the special edition hats that are 'one size fits all' the Rapha/Club/Lightweight/Pro Team come in S/M and M/L sizes. The M/L sized ones are the only caps I can wear without getting a headache.
I wish they'd go back to sized hats.