TL*THE CONTACT OWNS TECH INTERNATIONAL VALVE STEMS, MODEL TR413. WHILE DRIVING 70 MPH, THE REAR TIRE ON THE VEHICLE SUDDENLY FLATTENED. THE CONTACT NOTICED THAT THE VALVE STEM CAP AND CORE WERE BOTH MISSING. THE TIRES HAVE NOT BEEN DIAGNOSED BY THE DEALER. UPDATED 10-07-08 *BF THE CONSUMER STATED HE HAD A NEW VALAVE CORE AND CAP PUT ON THE BIKE AND THE NEXT DAY WHILE RIDING, THE TIRE WENT FLAT AGAIN. THE CONSUMER BELIEVED THERE WAS A DEFECT WITH THE VALVE STEM. UPDATED 10/09/08. *JB