Horizontal Extension Spring Counterbalance

By Huu Khanh Nguyen · Updated October 28, 2026 · sectional-door, counterbalance, extension-spring, clopay, amarr, garaga, wisniowski, garador

Extension springs lying along the horizontal tracks of a sectional door, with a sheave and a safety cable on each side.

Parameters

Name	Default	Unit
Door width	2438	mm
Door height	2133.6	mm
Shaft or track height above the door top	330	mm
Shaft position	front
Backroom beyond the door height	457	mm
Track depth behind the door plane	Math.min(doorHeight + backroom, 3813)	mm
Spring length	635	mm
Spring windings	Math.round(springLength / 3) - 1
Depth	trackDepth	mm
Height	doorHeight + shaftOffset	mm