What is the actual gear ratio of a mamachari(Japanese city bike) single?

Since the bike makers (Bridgestone, Miyata, Maruishi) don’t list gear ratios on their websites, I actually looked up the gear ratios of mama-chari singles (in the 10,000 to 20,000 yen range) to see what they were. I counted the number of teeth of front and rear gears at a bicycle shop. Only three of them…

Since it’s a mamachari, it often has a chain case on it, so you can’t see it.

As a result, as far as I checked the three bodies, even considering the miscounting, the gear ratio is 14~15T in the front and 32T~33TT in the rear, so the gear ratio is 2.13~2.35. If we assume that the tire size is 26 x 1-3/8, which is common for 26 inch mama-chari, the tire outer diameter is 668mm, so the distance that can be traveled by one pedal revolution is about 4.48 to 4.95m.

Calculating the distance traveled per pedal revolution

Tire size