I can easily get either my 3/4 Large Bell or my modular HJC Large helmet to go easily into the Highline BMW box. They do need to be upside down and sideways as already mentioned. I put a small piece of carpet cut to fit the bottom of the box which makes it a bit nicer. My scoot came with the BMW liner bag which is very nice, fits perfectly, is made of good quality fabric and quite handy. I've owned all models of Goldwings from the 1000 to the 1800 and believe I can carry as much in my GT as I could in those bikes.