Outside diameter: 70.5mm
width: 10.8mm
Inner hole: 3mm
with the 3mm diameter optical axis, or the motor shaft
through the belt can be slow, high efficiency to transmit power. The diameter of the wheel is bigger, it can be done with the rubber outer ring of the tires for intelligent, economy and strong cars.
benefit
1: the noise is low
2: the assembly is not strict
3: low power loss
4: DIY easy