Tires designed for tubes have a special, smooth liner to help eliminate the xtra friction caused by the tire and tube chafing against each other while the tire is flexing. They also use a powder similar to talc to reduce friction. Tubeless tires will have different liner designs depending on manufacturer. Some have a dimpled pattern, some a shallow fin like patern. These liners are not compatible with tubes. Radial tubes are different in that they are made of natural rubber, not synthetic.
