Engineering a notched belt can be a balancing act among flexibility, tensile cord support, and stress distribution. Precisely designed and spaced notches help evenly distribute tension forces as the belt bends, thereby assisting to prevent undercord cracking and extending belt life.

Like their synchronous belt cousins, V-belts have V Belt 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 array of V-belts that are extremely application particular and deliver vastly different degrees of performance.
Unlike toned belts, which rely solely on friction and may track and slide off pulleys, V-belts have sidewalls that fit into corresponding sheave grooves, offering additional surface and greater stability. As belts operate, belt stress applies a wedging force perpendicular with their tops, pushing their sidewalls against the sides of the sheave grooves, which multiplies frictional forces that permit the drive to transmit higher loads. How a V-belt fits in to 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 flexibility to bend around the sheaves in drive systems. Fabric materials of varied types may cover the stock material to provide a layer of protection and reinforcement.
V-belts are manufactured in a variety of industry regular cross-sections, or profiles
The classical V-belt profile dates back to industry standards developed in the 1930s. Belts manufactured with this profile can be found in a number of sizes (A, B, C, D, E) and lengths, and are widely used to displace V-belts in old, existing applications.
They are used to replace belts on industrial machinery manufactured in other parts of the world.
All the V-belt types noted over are usually available from producers in “notched” or “cogged” variations. Notches reduce bending tension, enabling the belt to wrap easier around small diameter pulleys and permitting better temperature dissipation. Excessive high temperature is a significant contributor to premature belt failing.

Wrapped belts have a higher resistance to oils and intense temperature ranges. They can be used as friction clutches during set up.
Raw edge type v-belts are better, generate less heat, enable smaller pulley diameters, increase power ratings, and offer longer life.
V-belts look like relatively benign and simple pieces of equipment. Just measure the top width and circumference, find another belt with the same sizes, and slap it on the drive. There’s only 1 problem: that strategy is about as wrong as you can get.