Ratcheting straps are available in a wide variety of sizes and styles. Typically used on flatbed trailers, moving trucks, pickup trucks, car trailers, or even vehicle roof tops, standard ratcheting strap assemblies are usually made with a flat webbing material.
They may employ ratcheting mechanisms on both ends of the strap, but more typically there is only one. The other end of the strap my employ a flat steel hook or claw, or may use a combination of chain link and hook. In either case both assemblies are attached to the strap by overlapping material and heavy duty stitching.
The most popular webbing material is polyester webbing. This type of strapping material is extremely strong, with near zero stretch, and can keep a load perfectly secure. In some instances the type of load you are securing may require a bit more “stretch” in your tie downs to absorb shock and vibration. In this instance nylon webbing may be a better choice. The load limit is not as high but it provides a bit of “give”.
Standard ratcheting straps are available in one, two, three, and four inch widths with breaking strengths up to 20,000 lbs. However, the real working load limit of a ratcheting strap assembly is limited to it’sratcheting mechanism and attachment points. Realistically even four inch wide ratchet strap assemblies are limited to a working load limit of around 5,000 lbs.
As the working load limit requirements increase, different attachment or securing mechanisms are employed, including steel hooks, or welded chain assemblies.
Below are the breaking strengths and working load limits (WLL) of standard size ratchet strap assemblies and are compared to other materials commonly used for tie down tasks.
Polyester Webbing Breaking Strength Ratchet Assembly WLL
1 inch (25mm) 4,000 lbs 400 lbs
2 inch (25mm) 10,000 lbs 3,300 lbs
3 inch (25mm) 15,000 lbs 5,000 lbs
4 inch (25mm) 20,000 lbs 5,000 lbs
½ inch Manilla Rope 315 lbs
½ Polyester Rope 960 lbs
½ inch Nylon Rope 525 lbs
½ inch Polypropylene Rope 625 lbs
½ inch Wire Rope 3,500 lbs
½ inch Grade Chain 11,300 lbs
The ratings of various materials, and mechanisms used for attachment and tightening in load hauling and securing are regulated by several different organizations including the Department of Transportation DOT, the North American Cargo Securement, Web Sling and Tie Down Association WSDTA, and the Commercial Vehicle Safety Alliance CVSA. These organizations test components and methodologies and create guidelines which may form the basis for actual laws and regulations.
The best source of ratings and proper usage for maximum safety can be found in the North American Cargo Securement Handbook which may be found online with a simple search.
Although these organizations provide guidance for the design and use of load securing systems, it is the product manufacturers who are ultimately responsible for their product designs and communicating to the users their proper use and limitations. Most often manufacturers communicate ratings and load limits to the user by stamping metal components with ratings codes or printing them on the strap webbing material.
Apart from the materials and assemblies used in the construction of ratcheting strap systems, the method in which they are employed are as at least important, if not more so. Although a 5,000 lb load limit may not sound sufficient to secure a 5,000 lb vehicle on a trailer, a single strap would never be used. The Department of Transportation specifies a minimum of four anchor points must be used to secure any load. In addition, the attachment points for the load must be such that no point on the load and it’s anchor have an angle of more than 45 degrees. Keeping the angle shallow limits the motion of the load.
