Engineering a notched belt can be a balancing act among flexibility, tensile cord support, and stress distribution. Precisely shaped and spaced notches help evenly distribute stress forces as the belt bends, thereby assisting to prevent undercord cracking and extending belt lifestyle.
Like their synchronous belt cousins, V-belts have undergone tremendous technological development since their invention by John Gates in 1917. New synthetic rubber substances, cover materials, construction strategies, tensile cord advancements, and cross-section profiles have resulted in an often confusing selection of V-belts that are extremely application specific and deliver vastly different levels of performance.
Unlike smooth belts, which rely solely on friction and can track and slip off pulleys, V-belts have sidewalls that match corresponding sheave grooves, offering additional surface and greater balance. As belts operate, belt tension applies a wedging pressure perpendicular to their tops, pressing their sidewalls against the sides of the sheave grooves, 
which multiplies frictional forces that permit the drive to transmit higher loads. What sort of V-belt fits into the groove of the sheave while working under pressure impacts its performance.
V-belts are produced from rubber or synthetic rubber stocks, so they possess the versatility to bend around the sheaves in drive systems. Fabric materials of varied kinds may cover the stock material to supply a layer of security and reinforcement.
V-belts are manufactured in various industry regular cross-sections, or profiles
The classical V-belt profile dates back to industry standards created in the 1930s. Belts manufactured with this profile can be found in several sizes (A, B, C, D, Electronic) and lengths, and so are widely used to displace V-belts in old, existing applications.
They are accustomed to replace belts on industrial machinery manufactured in other areas of the world.
All the V-belt types noted above are typically available from manufacturers in “notched” or “cogged” variations. Notches reduce bending tension, allowing the belt to wrap more easily around small diameter pulleys and enabling better temperature dissipation. Excessive heat is a major contributor to premature belt failing.
Wrapped belts have an V Belt increased resistance to oils and extreme temperature ranges. They can be utilized as friction clutches during start up.
Raw edge type v-belts are better, generate less heat, enable smaller pulley diameters, enhance power ratings, and provide longer life.
V-belts appear to be relatively benign and basic devices. Just measure the best width and circumference, find another belt with the same dimensions, and slap it on the drive. There’s only 1 problem: that approach is about as wrong as you can get.