Hi Ncdan, 3-23-19
I went from Dunlop 200/60 R16 to Dunlop 180/70 R16. The differences are these:
200 series - width=8.23", diameter = 25.39", load = 963#@41 psi.
180 series - width=6.92", diameter = 26.2", load = 908@41psi.
The 180 is about 3% greater diameter. I notice a difference in cornering...narrowe r, slightly better lean and taller...slightly better lean. I imagine there is a bit of a speedometer difference...slight ly faster than speedo reading? However, motorcycle speedometers are always a bit off...tire pressures, temps, etc. Not an issue for me, I rely on GPS reading.