These pulleys are designed for chain drive roller blinds.
The original pulleys supplied with the blinds often skip steps, are noisy and do not support larger and heavier blinds.
Use the pulley corresponding the size and weight of the blind. Smaller blinds should use the standard. The stronger pulleys are only required if the motor is unable to deal with the load. They use a smaller diameter to increase the pulling force without overloading the motor.
No supports needed. Recommend printing with .15 layer height in PLA or PETG. Make sure to orient the hole on the top surface when printing. They are designed for a firm press fit.
The author marked this model as their own original creation.