I reported earlier today that I just installed a pair of PR 4's on my '11 R1200RT and planned to test ride this afternoon. Well I just got back from my ride and all I can say is WOW. Granted I only did about 100 miles and my reference is a pair of badly worn PR 3's but I am very impressed. This bike has never been this responsive to handling inputs. It simply falls into a turn simply by turning your head. Again, the RT has always had exceptional handling, but it seems that these tires simply take it to a whole new level. If there's a down side, after mounting the 4's the bike seems to have grown about a 1/2 inch. Admittedly I am vertically challenged but the ground is noticeably further away with these tires. It's nothing that's not manageable just different. Anyway, initial impressions are very positive.