This 298:1 ratio Micro Metal Gear motor from Pimoroni can achieve up to 75rpm and its small size makes it ideal for small robot platforms or other light mechanical loads. It has a 3mm diameter D-shaped output shaft which is 9mm long and a 1mm diameter back shaft which is 4.5mm long. The back shaft is a great spot to install an encoder to track the motor's speed and position. It is part of a range of motors that are all the same size allowing you to choose the one that's right for your next project.
A. Hi Craig, thank you for your question. Manually measuring gives the following: Motor body including gearbox: approximately 24mm x 10mm; motor shaft diameter 3mm with flat; length of motor shaft extends approximately 12mm from the front of the gearbox.