Simple wheel for those cheap yellow geared dc motors. Designed to fit very tightly onto the shaft. A rubber band may be placed along the outside of the wheel to provide a surprising amount of grip.

Depending on your Printers tolerences you may need to scale the part up slightly if the wheel does not fit the shaft.

The wheel was printed on a creality CR-10 and used for a line following robot.

I hope this proves usefull to you!