Soft and quiet rubber. Doesn't hum when driving on dry pavement. It wicks water well, maintains control in deep puddles, and likes excellent traction in the rain. Rubber with a strong side, protects when rubbing with a curb. Rubber has excellent rolling resistance. On wheels drove only about 20,000 am. Braking distance on a dry road at high speed (about a hundred), I think about 30 meters or so.