# Chain length and sprocket spacing
# Scope: Approximate chain pitch count, rounded to an even number.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

pitch = 12.7 mm
driver = 15
driven = 45
center = 400 mm

pitchCount := 2*center/pitch+(driver+driven)/2+(driven-driver)^2*pitch/(4*pi^2*center)
evenPitches := 2*ceil(pitchCount/2)
length := evenPitches*pitch [mm]

check length budget: length <= 1300 mm

scenario alternative: pitch = 10.16 mm