A method and apparatus for enhancing the damping of pneumatic tires employed on vehicles employing sensors disposed within the tire volume to detect road induced vibratory forces. A gas pump under control of the sensor through a servo-system either forces gas into the interior tire volume to enhance pressure increases induced by road forces or exhausts air from that chamber when the vibratory forces are reducing the pressure in the chamber. The air from the pump passes through capillary passages to create frictional losses which tend to damp vibratory forces on the tire.