This is a robot drive wheel we had made specifically for us. It does not have a bearing. Its 6 inches in diameter. 1.9" inches wide. Its a rubber pneumatic tube tire. The rim has a 4 bolt pattern so you can easily mount it to a flanged hub.
This is a MLT-42-F tracked robot platform and is equipped with flipper arms, 42mm motors, a motor controller, and FLYSKY remote control. This rugged robot platform the treaded robot handles up to 15lbs of additional payload and travels 134ft/min.