Replacement rubber skirts for the Typhoon are almost impossible to find. For as old as they are they crack and split a lot.
A simple and cheap solution I've found is to remove the skirt, turn it inside out and coat it with black silicone. You can buy it at any auto parts store or at Wal*Mart. Once dry turn it right side out and spray it down good with Armor all or a similar rubber treatment. This will keep the outside plyable and lookin new. Hope this help