I love it when science fiction comes to life.  Neil Stephenson had these in 
Snow Crash (1992), both on motorcycles and skateboards.  
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				Smart wheels use sonar, laser range finding and millimeter wave radar to identify mufflers and other debris. Each one consists of a hub with many tiny spokes. Each spoke telescopes into five sections. On the end is a squat foot, rubber tread on the bottom, swiveling on a ball joint. As the wheel rolls, the feet plant themselves one at a time, almost glomming into one continuous tire. If you surf over a bump, the spokes contract to roll over it. If you surf over a pothole, the rubber prongs probe its asphalt depths.
			
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