Tire Sold Separately 24 x 1.75 Tire & Insert Combo     The Trick To Inserts   The trick to inserts is getting the right sized tire. If the tire is too big, a gap will develop between the tire and the insert and will reduce efficiency. If the tire is too small, then you'll never get the insert inside of the tire. These are not "NoMorFlats", instead these are harder and tougher. This is the system you should have for high weight, slow speed and when you cannot have a tire failure. We offer some grey non marking tires but you can use any tire as long as it will fit. Our inserts are the choice of the US Military, Industry and  Businesses around the world. These are not wimpy inserts. If some one were to ask us what to use to go hunting with or for Emergency use, then the Air Free Inserts are just what the doctor ordered. Complete Tire/Insert Systems from $40 Bucks "The Grey Rubber Tires that we sell are non marking, and are just like any other tire and will last just as long as a black rubber tire.". 12 1/2 x 2 1/4 Knobby Rubber Tire 16 x 1.75 Street Tread Rubber Tire 16 x 2.125 Lug Tread Rubber Tire 20 x 1.75 Street Tread Rubber Tire 20 x 2.125 Lug Tread Rubber Tire 24 x 1.75 Street Tread Rubber Tire	Inserts are one of the easiest and best ways to fix flats forever. Its' simple. Just put the insert inside of a matched rubber tire and the more you use it, the better it works. This is a mission critical tire system. These inserts when properly matched to a tire and rim will be EMS (Emergency Medical Services) grade. Perfect for: Garden Carts, Marine Carts, Pony Carts, Wagons, Trailers, Wheelchairs, Hunting Carts, etc...                " couldn't be easier ! "       Inserts fit plastic mag and steel box type wheels. Your rims need to be deep and wide for our inserts to seat themselves properly. Not for use on bicycles, these are stiff, tough inserts meant for slow speed high weight situations. Installs easily with screwdrivers. Tire Sold Separately 12 1/2 x 2 1/4 Tire & Insert Combo