A large extension spring for garage door counterbalance, zinc plated against the condensation that forms in an unheated garage. The spring carries the weight of the door through its whole travel, which makes both its force curve and its safe retention critical.
Counterbalance springs are specified from door mass, drum geometry and travel, and are made to that rather than to a nominal size.
Garages swing between cold and damp. Zinc plating handles the condensation that would rust bare steel within a season.
Hook geometry is made for the brackets and cables in door hardware rather than for a generic pin.
Always fit garage door springs with a containment cable through the body. Release the door's weight before removing or adjusting any counterbalance spring.
Doors becoming heavy to lift as the counterbalance spring loses force
Corroded door springs that fail without warning under full load
Dimensional and load figures are set per order against your drawing or sample, so they are marked TBC rather than filled with catalogue numbers.
| Product Type | Tension Springs |
|---|---|
| Raw Material Options | Stainless steel, Spring steel, Carbon steel, 65Mn, Music wire |
| Wire Diameter Range | 0.1-8 mm |
| Surface Treatment Options | Zinc plating, Nickel plating, Silver plating, Gold plating, Tin plating, Galvanizing in various colours, Dacromet, Black oxide, Phosphating |
| Standard | ISO, non-standard and OEM drawings |
| Processing Route | Material sourcing → Coiling and forming → Heat treatment → Surface treatment → Quality inspection → Packing → Shipping |
| Inspection Equipment | Grinding and shot peening machinery; Precision tensile strength testers; Magnetic powder flaw detectors |
| Packing | Plastic bags, cartons or pallets, or packing to your own specification |
| Payment Terms | L/C, T/T, D/A, D/P, Western Union, 30% deposit before production, 70% balance before shipment |
| Lead Time | 7-15 days after the order is confirmed |
| Minimum Order Quantity | Quoted per part — tell us your requirement (TBC) |
| Dimensions and Load Rating | Made to your drawing or sample (TBC per part) |
Every batch follows the same seven step route, with tensile testing and magnetic powder flaw detection carried out before packing.
Available in Stainless steel, Spring steel, Carbon steel, 65Mn, Music wire, in wire from 0.1-8 mm, with any of our nine surface finishing routes. Geometry, end treatment and finish are all specified per order.
ISO 9001, SGS certificate and RoHS report (stated on the legacy site, certificates pending re-confirmation). Certificate copies are sent on request once re-confirmed.
Against a torsion bar counterbalance, extension springs are cheaper and simpler to fit but store their energy where it is more exposed, which is why containment matters more.
Door weight, the travel, the drum or pulley arrangement, and the installed length available. Existing spring dimensions help if you have them.
Tell us your expected cycle count and we will design to it. Door springs are consumable items and should be planned for replacement.
Containment is strongly advisable on door springs. Tell us your arrangement and we will supply parts that suit it.
Send your drawing, dimensions or a sample. We will confirm the specification and come back with a price and a lead time.