I had a question from a certifier. He received an application on which the constant was around 14000 counts per kilometer, which would indicate that a very small wheel was used. He was puzzled.

I mentioned that the new version of the Jones/Oerth counter - the one with the plastic gearbox - records about 30 counts per revolution of the wheel.

The original Jones recorded 20 counts per revolution.
The original Jones/Oerth recorded 23.636363.... counts per revolution.
Some early versions exist that recorded 26 counts per revolution.

If in doubt, ask about the counter.