Tube Type is the standard for bicycle tires. It mounts to the rim of bicycle wheel with a steel wire bead or an Aramid folding bead, and is inflated with a tube that is placed inside of the tire. The benefits of tube type tires is that they are the least expensive type of tires as well as offering the largest range of sizes and tread styles.
UNIVERSAL SYSTEM TUBELESS (UST)
Tubeless UST (Universal System Tubeless) tires, when mounted onto a UST rim, form an air tight bead lock, negating the need for a tube inside of the tire. The air tight seal is achieved by increasing the thickness of the rubber compound across the side walls of the tire as well as changing the shape of the tire bead to match with the UST standard. The benefits of this system include the ability to ride at lower air pressures, giving the rider more tire contact with the ground, and eliminates the tube as a separate component that can be punctured.
SEALANT COMPATIBLE (SCT)
Sealant Compatible (SCT) tires can be considered a cross of a tube type and UST type tire. When used with a liquid sealant, SCT tires form an air tight seal, similar to the UST tire, but can be used on almost all bicycle rims. SCT tires have an additional layer of material built into the casing of the tire that allows it to be compatible with the various chemicals in liquid sealants; however this material is thinner and lighter than its UST counterpart. The benefits of SCT tires, when used with sealant, allows the rider to use lower air pressures as well as take full advantage of the liquid sealant compound when it comes to sealing most punctures or cuts in a tire.
Tubular tires are performance orientated tires in which the tube is sewn into the casing of the tire. The tire is then glued onto a rim. Tubulars are primarily used for road racing because of their higher cost and difficulty in mounting. The benefits of tubulars include the ability to run at significantly higher pressures, some tubulars have a max pressure rating of 200psi or higher. Tubulars also have a more supple feel to their ride compared to a tube type tire; this is due in part to the higher TPI fabric used to build tubular tires.