337.33  UNSAFE TIRES.
   No person shall drive or move on any street or public property any motor vehicle which is not equipped with tires having a minimum of one-sixteenth of one inch depth of tread on the road surface.  All tires shall be free of major bumps or bulges, breaks, thrown tread or any condition which would constitute an unsafe condition.
   Penalty - see Sections 307.01 and 307.02