The C3 will fit along the lines of the C3 RF-1000. Modulars typically fit a hair bigger than their fixed face counterparts, so I could see how a M would work vs an L in the 1000.
At 22 inches you are a 55.8 cm which is on the low end of a medium, though. This is a bit of a dilemma. There are many folks out there wearing a helmet a size too big.
The C3 is an intermediate oval shape.
Worst case you order (we ship free) a M and if it is too small, send it back and we will ship you the new size for free as well.
For the level of investment, you want it to fit perfect. My gut is a medium will work.
Originally Posted by Nesbocaj
...also a sizing question: I wear a Large in the RF-1000 and a Medium in the Multi (Shoei's) any guidance in sizing? (22" measurement)