I have an 00 M750, a Buell S1W..and an R1....and I can tell you this...there are alot of people that say they can feel the difference between a 170, 180, and 190 tire...but in my opinion it is the profile of the tire and not cross sectin they are feeling....my M750 is stock....my Buell I run D204's....the R1 I run whatever they have in stock...but I feel the most difference when I go from a Dunlop 208 to a BT-010....same size.....alot of people say they feel the smaller tire turns in faster..but on the street I do not feel you will tell the difference............On the open bikes I run WIDE rear tires cuz they look cool......on the R1 I stay with the factory size...cuz hell its a 190 for crying out loud....it looks good and I feel confidenet running it