Tension Wheel

A tension wheel is a spoked wheel attached to the tension shaft inside a commercial rolling steel door's barrel assembly. The wheel connects to the internal counterbalance spring. Rotating the wheel winds or unwinds the spring, increasing or decreasing the force it applies to the barrel to offset the curtain's weight.

The need for adjustment arises from two sources. First, installation requires dialing in the spring tension to match the actual curtain weight. Second, springs lose some tension over time, so a technician will re-tension by turning the wheel a quarter-turn or half-turn at a time.

A correctly tensioned door holds at any height when released manually. If the curtain falls freely when released, the counterbalance tension is too low. If it rises on its own, the tension is too high. Both conditions place strain on the chain hoist or motor operator and increase wear on the drive components.

The tension wheel is located at the head of the door opening, mounted to the bracket that supports the barrel. Most wheels have pre-drilled holes around the perimeter used to lock the wheel in position with a pin or set screw once the correct tension is found.

The tension wheel's function in a rolling door is equivalent to the winding cone on a sectional door's torsion spring. Both devices set the amount of stored energy in the counterbalance spring to match the door's weight and travel distance.