On my 1100GS, one is a little larger, and will fit a helmet, even a Shuberth. But I hadn't tried to put those bags on the K100, though I don't see why they wouldn't mount. The K75 bags won't take the Shuberth. I use cable locks, cause the bags are already full of other stuff, and if I'm not hauling stuff, I don't ride with empty bags.So...........inquiring minds want to know, are 1985-1996 tragkorbs ( why do we use a French words for a German bag?), interchangeable for mounting on K75/100/1100? We should ask Laitch, he will know.