system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why don't/can't motor vehicles have spherical wheels like in "I, Robot"?
gpt
A spherical wheel just isn't practical. A sphere is going to have a small contact patch for the size of the wheel compared to a normal wheel. They would be hard to manufacture as well. 

A car COULD have spherical wheels, but it just doesn't make sense to have them.