Okay, so can anyone help me out with this problem I'm having getting new rubber on my bike. I'd like to get a set of Heidenau, but they haven't made a set yet for my GS (not in production yet). It was pointed out to me, that the slightly smaller tire size can be used (110/80 19; 150/70 17, instead of the stock 120/70 19; 170/60 17). There maybe a couple of options for me with the smaller size, but almost everything appears to be back-ordered until July. I'm making a trip to Canada at the end of this month, and would really prefer to change out my tires before heading out. Please, any suggestions, and or could the smaller size work on my GS? Thanks for any input.