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How to Identify a V-Belt or Timing Belt

4 min read

Belts drive fans, pumps, conveyors and compressors. Most have a code printed on the back, but when it's worn off you can still identify a belt by its shape and size. The two families work differently.

V-belts (friction drive)

A V-belt is identified by its cross-section and its length:

  • Classical sections: A, B, C, D (by top width) — e.g. an 'A42' is an A-section, 42 in long.
  • Narrow/wedge sections: 3V, 5V, 8V (or metric SPZ, SPA, SPB, SPC).
  • Fractional: 4L, 5L. Cogged versions add an X (e.g. AX, 5VX, BX).
  • Length is in the code; if missing, measure the inside or outside circumference.

Timing belts (toothed, synchronous)

  • Tooth pitch: imperial MXL, XL, L, H, XH; metric T5, T10; curvilinear HTD 3M/5M/8M/14M and GT2/GT3.
  • Number of teeth (or overall length) and the belt width.
  • Example: '535-5M-15' = 535 mm long, 5M pitch, 15 mm wide. '240L075' = 24.0 in long, L pitch, 0.75 in wide.

Cross-referencing belts

Belts from Gates, Continental/ContiTech, Optibelt, Dayco and Bando cross-reference directly when the section/pitch, length and width match. Send us the printed code or your measurements and pulley pitch, and we'll match the right belt.

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How to Identify a V-Belt or Timing Belt | AllPartsIn