These two large (120mm-diameter) wheels from Dagu Electronics are ideal for custom robots that need to traverse complex, rugged terrain.
The black tires are made of soft, spiked rubber for increased traction. The included adapters let you easily mount the wheels to motors with 4mm output shafts. These wheels are sold in pairs: you get two wheels, two 4mm adapters, and one 3mm hex wrench that matches the adapter screws.
The hex socket on the hub is 12 mm from side to opposite side.
An included pair of adapters lets you easily mount the wheel to motors with a 4mm output shaft, such as the 25D mm metal gearmotors found on the Dagu Wild Thumper chassis. A 3mm hex (or Allen) wrench is included for use with the adapter screws.