Related Resources: belt design

Synchronous Timing Belt Pitches

Belt Drive Design and Engineering
Mechanical Gear Design and Engineering

Standard Synchronous Timing Belt Pitches Imperial Units per. ANSI RMA IP-24, ISO 5299 and IS 9804.


ANSI RMA IP-24 Conventional trapezoidal, or rectangular tooth, timing belts come in six cross sections, which relate to the pitch of the belt. Pitch is the distance from center to center of the teeth. The six basic cross sections or pitches are MXL (mini extra light), XL (extra light), L (light), H (heavy), XH (extra heavy), and XXH (double extra heavy)

Synchronous belt sizes per. ANSI RMA IP-24 are identified by a standard number. The first digits specify the belt length to 0.1 inch (2.54 mm) followed by the belt section (pitch) designation. The digits following the belt section designation represent the nominal belt width times 100. For example, an L section belt 30.000 inches pitch length and 0.75 inch in width would be specified as a 300L075 synchronous belt.

The RMA nomenclature for double-sided belts is the same as for single-sided belts with the addition of the prefix “D” in front of the belt section. However, some manufacturers use their own designation system for double-sided belts.

All dimensions are given in inch units

Standard Synchronous Timing Belt Pitches

Synchronous Belt Standard Pitch Lengths and Tolerances ANSI/RMA IP-24, ISO 5299 and IS 9804.


ISO 5299
IS 9804
Machinerys Handbook, 27th Edition