writes:

2012 cm? Are you sure?

Context, from Mr. Muzi:
Popular bike computers use input in cm (rollout for a road bike is
about 2012cm)and offer choice of either unit for display. That seems
to indicate number manipulation is metric until final display if miles
are selected.

Looks like I am using 2143 cm for 622x28 tires.
(2143/pi - 622)/2 = 30 cm seems about right.

Perhaps (2012/pi - 559)/2 = 41 cm makes sense for mountain bikes?