Overhead doors operate on a counterbalancing system where springs under tension transfer lifting force through cables to the bottom brackets. Garage doors and truck doors have a cable installed on each side of the door generating equal upward force to open the door.

Cables come in a variety of lengths, diameters, styles and materials to best fit each individual door application. The most common types of cables are torsion cables, extension cables, safety cables and truck door cables. The more popular cables come in standard stock sizes, but cables can also be highly customized for unique door setups.

1. Types of Cables

• Torsion Cables – These cables consist of a plain loop end with a sleeve that hooks around the bottom brackets. They also contain a stop end that fits into the groove of the drums. Standard torsion cables are typically the door height +18″. The added length of the cable is designed to wrap around the drums to take all force off the stops. Non standard torsion cables designed for high lift, full vertical lift, rear torsion or follow the roof pitch applications must be calculated with garage door engineering software. Residential doors utilize 3/32″ and 1/8″ torsion cables while commercial doors may require 5/32″ , 3/16″, 1/4″ or 3/8″ depending on the garage door weight.

• Extension Cables – Designed for doors utilizing extension or stretch springs, these cables differ from torsion in that they are much longer and typically only include a loop (sleeve) end. In situations where fraying is a concern a stop can be added. These cables are typically 3/32″, 1/8″ and 5/32″ and almost exclusively used on residential doors where headroom is a concern. Safety cables, also called containment cables run through the hollow area of extension springs, so that when they break the pieces of spring don’t fly around the garage damaging person or property.

• Truck Door Cables – Sectional doors are also found on some types of box trucks such as Whiting & Todco. The cables on box truck doors are very similar to standard garage door torsion cables, but are typically made more durable. A thimble is inserted inside the loop end of the cable to prevent fraying from the bottom brackets. Since the cables on a box truck run outside the door vs inside like on a garage door it is crucial that they are made of stainless steel vs standard galvanized aircraft cable. Exposure to elements like moisture, salt and general wear and tear from frequent use make durability extra important.

2. Cable Diameter Size

The size of the cable is actually referring to the wire diameter and thicker wire diameters are designed to accommodate heavier garage doors. In other words the larger the cable diameter, the higher the cable breaking strength. Thicker diameters also provide added protection against fraying, corrosion, rust, dents and cuts.

Light weight residential doors can use 3/32 or 1/8 inch diameter. Larger residential doors or heavier wood doors would use 1/8″ or possibly 5/32″.  Commercial doors can use 5/32″ diameter up to 3/8″ for industrial applications.

The type of drums the garage door uses will limit the size of cable that can be used since the grooves on the drums can only accommodate up to a certain manufacturer specified wire diameter. For example a common residential drum is the OMI-8. These cables have a maximum threshold of 1/8″ although they also support the smaller 3/32″ diameter. Generally speaking you should use the maximum diameter cable specified by the drum manufacturer for increased durability and longevity. 

3. Cable Materials

4. Parts of Cable Assemblies

5. Breaking Strength Rating

6. Replacing Broken Cables

7. Replacing Broken Cables

8. Replacing Broken Cables

9. Replacing Broken Cables

Cable Breaking Strength – Galvanized, Stainless, Zinc-Aluminum

What are cables made of?

Garage door cables are made of galvanized steel in a process known as “hot-dip galvanizing” (HDG). This involves immersing the cables in molten zinc forming an outer layer of corrosion protection. For more detailed information on this process visit GalvanizeIt.org. The average homeowner should use standard galvanized aircraft cable (GAC), but a few other options are available for added rust protection.

• Galvanized Steel (Hot Dip) – Standard garage door cable with some corrosion protection at the lowest cost – $
• Zinc-Aluminum Coated Steel – 3X more corrosion resistant than GAC, at 50% higher cost – $$
• Stainless Steel – Maximum corrosion protection, at 200% higher cost. – $$$

For damp environments, stainless steel or zinc-aluminum should be used for maximum corrosion protection. Zinc-aluminum coated cables offer 300% greater corrosion protection than standard galvanized cables, at a lower cost than stainless steel cables. ZN-AL cables have a protective coating made up of 95% zinc and 5% aluminum.

How much does it cost to replace garage door cables?

Can you open the garage door with a broken cable?

How much does cable repair cost?

Why do garage door cables break?

What sizes are garage door cables?

Standard Lift Cable Lengths

What are garage door cables made out of?

What parts of the garage door cable?