Engineering a notched belt is definitely 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 helping to prevent undercord cracking and extending belt existence.

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 methods, tensile cord advancements, and cross-section profiles have resulted in an often confusing selection of V-belts that are extremely application particular and deliver vastly different levels of performance.
Unlike smooth belts, which rely solely on friction and may track and slide off pulleys, V-belts possess sidewalls that fit into corresponding sheave grooves, providing additional surface and greater balance. As belts operate, belt pressure applies a wedging push 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. What sort of V-belt fits into the groove of the sheave while operating under pressure impacts its performance.
V-belts are manufactured from rubber or synthetic rubber stocks, so they have the flexibility to bend around the sheaves in drive systems. Fabric V Belt materials of various types may cover the stock material to provide a layer of safety and reinforcement.
V-belts are manufactured in various industry standard 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 many sizes (A, B, C, D, Electronic) and lengths, and are widely used to displace V-belts in old, existing applications.
They are used to replace belts on commercial machinery manufactured in other areas of the world.
All of 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 easier around small diameter pulleys and enabling better heat dissipation. Excessive warmth is a significant contributor to premature belt failure.

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