Full definition
High Torque Drive — a curvilinear (circular-arc) tooth profile system for synchronous belts, developed by Gates Corporation in the 1970s as a major improvement over trapezoidal tooth profiles. The rounded tooth shape distributes stress more uniformly across the tooth root, increasing load capacity by 40-70% versus classical trapezoidal teeth and virtually eliminating tooth jumping under shock loads. Standard pitches: 3M (3 mm), 5M (5 mm), 8M (8 mm), 14M (14 mm), 20M (20 mm). Per ISO 13050. The successor profile GT/GT3 (Gates PowerGrip GT) further optimizes tooth geometry for even higher capacity and smoother engagement. HTD pulleys are not interchangeable with classical (trapezoidal) timing pulleys despite similar pitch. Widely used in machine tools, packaging, and industrial automation.