These wheels are designed to press-fit securely onto the 3mm D output shafts on many of our gearmotors, including our micro metal gearmotors and our mini plastic gearmotors. They also work with our 35:1 and 115:1 15.5D metal gearmotors, as well as with our selection of Solarbotics metal gear motors. The wheels have silicone tires and measure 90 mm (3.54?) in diameter. Six additional mounting holes for 4-40 screws make it possible to use the wheel with any of our universal mounting hubs. The slots in the six spokes allow additional accessories to be mounted to the wheel (e.g. decorations or parts of an encoder system).
Note: Our high-traction sticky tires can be stretched to fit around the hubs of these 90×10 mm wheels, but the fit is not great, and you might need to use glue to keep them on the hubs.
The left picture below shows this wheel mounted to a 37D mm metal gearmotor with a universal mounting hub for 6mm shafts, and the right picture below shows this wheel mounted to a micro metal gearmotor.