I've got a problem (some would say I have many problems). I seem to generate lots of heat on the top of my head. Enough that I leave the vents open on my helmet when the temperatures are in the forties. I've been looking for a helmet that has really great venting. I'm starting to think that what I want doesn't exist. I've tried half shell helmets. They keep your face and ears cool but no air flow gets to the top of my head. I went back to my Shoei RJ Platinum helmet. I tried the GMax 27S. It has lots and lots of air channels inside and vents on the back that make you look like Godzilla. I went back to the Shoei helmet. Here's what I think I've learned. My Shoei helmet is just a touch large for me. That GMax helmet fit me exactly. I'm thinking that the Shoei flows the air better because it is not pulled as tightly on my head. Because of that I'm considering the GMax 27S in the next size up. I could always go helmetless but I'm not comfortable with that idea. I've whacked my head so many times over the years that I feel like I need the protection. Has anybody discovered a DOT helmet that has really good airflow through it?