I have a Nolan Trilogy modular helmet that fits into the saddlebag of the F6B (along with a couple of pairs of gloves, my gerbing heated liner, small bag of bungys, small tool bag, and my rain pants). I like to have the helmet for cold/inclement weather (rain shower on a 2-6 hour ride?). The bags on the '18 are much more angular and will not fit a helmet. To me that's a huge downer if not a deal breaker.