I have the same problem. But I kept trying different brands and they all fit way different. The HJC's XXL actually fits my head great. Also found a lot of XXX on the web but I didn't want to buy one with out trying it on, glad I did that.
Arby, I have a huge melon as well. The only XXX that fits is HJC's CL-SP. HJC also came out with a newer version that may be better yet but haven't found it on the shelves yet to try it. Hope this helps put a helmet on that grape!
this joerocket only goes up to 2xl, but i had to downsize, and another half size smaller wouldnt hurt either
so the 2xl should fit like a 3xl compared to most brand sizing
also the BELL helmets fit similarly
and they go up to 2xl
i was referring to the HYBRID helmet specifically
which i dont think hjc makes an hjc version of
i wear a medium in normal joe rocket helmets, but an almost XS in the hybrid joe rocket