with a 28'' wheel racing bike and a frequence 60:
If you have 42 / 26 , it means 12.8 km/h
If you have 45 / 15 , it means 24.1 km/h
If you have 52 / 14 , it means 29.9 km/h
with a 26'' wheel Mountainbike and a frequence 60:
If you have 42 / 26 , it means 11.9 km/h
If you have 45 / 15 , it means 22.0 km/h
If you have 52 / 14 , it means 27.8 km/h
1 km/h = 0.55 mph
(I think I calculated right, but excuse any faults
)
marmotte