Belt

Frequently asked questions — Belts

• What is the technical difference between a narrow V-belt and a classical V-belt?

  Narrow belts, designated SPZ, SPA, SPB and SPC to DIN 7753, use a wedging effect to multiply the grip factor. This design offers superior robustness and better tolerance to misalignment for fans, compressors and machine tools. Conversely, the classical sections Z, A, B, C and D to ISO 4184 are now reserved for legacy applications. Their gradual replacement by the narrow series is due to increased efficiency in power transmission.
• In which cases should a synchronous belt be preferred over a V-belt?

  The synchronous or toothed belt should be chosen for applications requiring a positive drive with no slip, thanks to the direct meshing between the belt teeth and the pulley teeth. Unlike V-belts that transmit power through friction, this technology is essential for precise positioning and axis control. Depending on your performance requirements, you can opt for trapezoidal profiles (MXL, XL, L, H, XH, XXH) or for the higher-performance curvilinear profiles such as HTD, STD, AT or GT.
• What are the advantages of Poly-V multi-rib belts?

  Poly-V belts, available in sections PJ, PK, PL and PM, combine the benefits of V-belt and flat belt designs. They stand out for their low thickness coupled with a high power transmission capacity, while ensuring quiet operation. This technology has become a standard for industrial appliance applications as well as in the automotive sector, where compactness and noise reduction are decisive factors in transmission system design.
• When is it preferable to use a flat belt rather than another type?

  Flat belts, manufactured from leather, reinforced elastomer or polyurethane, are recommended for specific configurations such as very high speeds or long-distance transmissions. They are commonly used in the paper and printing sectors. Although they offer excellent efficiency and allow unlimited lengths, they must have a precise tensioning system to operate correctly, unlike V-belts or synchronous belts which handle mechanical stress differently.
• Should I choose a standard V-belt or a cogged variant?

  For applications placing greater demands on the transmission, the cogged variants XPZ, XPA, XPB and XPC represent a relevant technical evolution. Thanks to their notched back, these belts deliver superior efficiency as well as a longer service life compared with standard narrow V-belts (SPZ, SPA, SPB, SPC). These variants retain the robustness characteristic of belts to DIN 7753, while improving flexibility and heat dissipation when running over small-diameter pulleys.