The following was originally posted here in another thread two weeks ago that I can't link to because I don't want to take the time to figure out how to do it.
MPH= (rpm x tire diameter) / (gear ratio x 336)
It gets a little more complicated because the R1200S has a step-up at the primary of 1:1.824 that needs to be accounted for. I think I am doing this right, but I'm sure one of the engineers will correct me if I'm wrong.
RPM is 8200
Tire Diameter is 26" (Pirelli 190/55zr17 slick)
Final Drive = 2.62
6th gear = .81:1
MPH = [(8200/1.824)*26] / (2.62*.81*336)
MPH = 116885.96 / 713.0592
MPH = 163.92
