The cleanup crew would always find a hub or two during highway clean up, they always came off of a what?\nOptions:\n- propeller\n- datahub\n- wash\n- car wheel\n- electric fan
Step-by-step reasoning process below:

User
Loose hubs from Cars running on highway come off the car wheel running at high speeds. The dropped hubs are found by the clean-up crew while cleaning. The answer: car wheel.
Assistant