From everything I have seen and heard so far the C3 seems to be an updated shape with it a slightly more round approach to your typical intermediate oval (Shoei, Arai) vs the previous round shape that fits more closely to an HJC or Nolan.
I am a Medium in the C3 and also am a med in the Arai XD-3, RX-Q, Shoei RF-1100 and Qwest.
The C3 is closest to the Arai RX-Q and Shoei Qwest which are basically medium ovals with slightly more room in the temples and sides.
Does that answer your question?
Originally Posted by lineareagle
Does sizing on the C2 translate directly to a C3?
I heard that they made the C3 more oval.
Love my C2 but its getting old almost 4 now!
BTW most safety organizations I have read say a white helmet is the most visible. Doubt these studies were done when hi Viz was available tho.