Full definition
International standard specifying the dimensions and tolerances of synchronous (timing) belt pulleys and belts with curvilinear (HTD — High Torque Drive) tooth profiles for power transmission. Covers pitch sizes: 3M (3 mm pitch), 5M (5 mm), 8M (8 mm), 14M (14 mm), and 20M (20 mm). ISO 13050 defines: pulley tooth and groove geometry (the distinctive circular-arc profile that distributes load more uniformly than trapezoidal teeth), belt tooth dimensions and tolerances, pulley outside and pitch diameters, and belt width designations. The HTD curvilinear profile (developed by Gates Corporation) provides 40-70% higher load capacity than classical trapezoidal timing belt profiles at equivalent pitch, and virtually eliminates tooth-jumping under shock loads. ISO 13050 is the reference standard for designing synchronous drives using HTD belts and pulleys. Note: HTD pulleys are NOT interchangeable with trapezoidal (classical T-profile) pulleys despite similar pitch values — the tooth geometries are fundamentally different. For GT/GT3 profiles (Gates' further evolution of HTD), refer to manufacturer specifications as these are not yet fully covered by ISO. Per ISO 13050:2014.