See Add Pulley
Use the Pulley dialog-box to edit the number-of-teeth around a Pulley.
The Pulley dialog-box has Read-only information:
•Pulley's Pitch Circle Diameter (P.C.D.).
•Tooth-Pitch (Edit the Tooth-Pitch parameter in the Motion-Path dialog-box).
•Belt Length (Edit the Target Belt Length parameter in the Motion-Path dialog-box, or edit the sketch directly).
To edit the Pulley:
As you edit the number-of-teeth, the radius of the pulley, and arc in the sketch-loop, will also change.
Driving-Pulley (pulley drives the belt) - or - Driven-Pulley (belt drives the pulley)
Pitch-Circle-Diameter - see Notes below
Tooth-Pitch - edit with the Motion-Path dialog-box
Belt Length - edit with the Motion-Path dialog-box
The radius of the Arc and Pulley is gray in the Part-Editor - to indicate it is read-only.
The Number-of-Teeth on the Pulley
and the Tooth-Pitch of the Belt, control the Radius Dimension of the Arc.