These universal mounting hubs are designed to work with most 3 mm diameter shafts, including round shafts, “D” shafts, and Tamiya’s 3 mm hexagonal shafts. Each of the two included hubs has four mounting holes for #4-40 screws (not included), letting you mount custom wheels or mechanisms to your motors. The two included #4-40 hex set screws (one for each hub) allow secure coupling of shaft to hub, and a 0.05″ hex wrench (often the smallest size in SAE Allen wrench sets) is included for use with the set screws. A dimension diagram of the hub is available under the resources tab.
The picture to the right shows a hub with one of Pololu’s mini metal gearmotors and a Pololu mini metal gearmotor bracket. These hubs will work with any Pololu mini/15.5D mm metal gearmotor or micro metal gearmotor, and they also work with 60 mm, 70 mm, 80 mm, and 90 mm Pololu wheels.