19T revs / speed
NeilSea - "With the 19T , what RPM are you spinning at 70mph?"
Indicated speed in 5th gear.
3500 rpm = 62 mph
4000 rpm = 70 mph
3500 rpm is useful as it's where maximum torque kicks in. The engine's running sweetly, economically, and urges forward strongly for overtaking.
Having tried 17, 18 and 19 T sprockets I've found the 19 to be more relaxed and the most suitable for my style of riding,
At the end of the day it comes down to personal preference, weight carried and the terrain.