POLYFLEX® JB™ Polyurethane multiple V-belt

Polyflex® JB™ is synonymous with high power density in small spaces. Developed by Gates and produced to patented manufacturing processes, Gates Polyflex® JB™ belts provide more load-carrying capacity at higher speeds to small precision multiple V-belt drives. This results in significant cost savings and improved design freedom. Polyflex® JB™ belts are recommended for use on bench type milling machines, lathe drives, woodworking and metalworking machine spindle drives, computer peripheral equipment, small blowers, etc. They are available in 3M-JB, 5M-JB, 7M-JB and 11M-JB sections.


  • Durable yellow marking indicating type and dimension


  • Truncated ribs ensure flexibility, reduce heat build-up and improve rib crack resistance .they also enhance load-carrying capacity on small diameter pulleys.
  • High modulus ,low stretch polyester tensile member provides superior resistance to fatigue and shock loads
  • All elastomeric rubber compound provides and oil heat resistance.
  • Specially formulated fibre reinforced undercord stock improves belt stability.


  • Extremely smooth and cool running.
  • Very high power capacity per rib
  • Long life due to extra load carrying capacity
  • Improved performance on back idllers
  • Smaller drive package
  • Tolerant of pulley groove debris
  • Static conductive (ISO 1813) and can as such be used in the conditions describes in the Directive 94/9/EC -ATEX

Micro V belts are available in PJ,PK and PM cross sections .The figure below shows a cross sectional view illustrating the nominal belt dimensions rib width and belt height.All these belts will operate in standard pulleys provide the pulleys are manufactured to the DIN 7867 or ISO 9982 standard for the specific cross section

Belt Sizes