All Things About Ratchet Straps For Trucks
The ratcheting tie downs are the assembly of webbing and ratcheting buckle , it’s a widely known fact, by this logic the cam buckle strap is just the cam buckle with tie down strap, why I am not surprised? Cam buckle tie downs are only for light duty use, and 2” cam buckles are the biggest size we will see in the real world use, and it’s still light duty. Compare to cam buckle the ratchets are stronger and more widely used, the available sizes of ratchets are 1”,2”,3” and 4”, and the ratchet buckle generally has higher working load limit than the cam buckle, the typical working load limit for 2” tie downs is 3,333lbs, for 3” and 4” which is 5,400lbs, since these tie downs have design factor of 3:1, the minimum breaking strength is 10,000lbs and 16,200lbs.
Of course what we discussed above is mainly for flatbed trucks and some other kind of vehicles, in reality semi trailers are much more than flatbeds in numbers, since they are box trucks the tie down needs are different, you will see most semi trailers have E Track installed and use logistic straps . It is estimated that 80% trucks are box trucks, and the e track tie down system is just for semi trailers , so e track straps are most popular tie down straps. And these straps are not as strong as the one we use on flatbed truck, the working load limit of typical e track straps is 1,000lbs, with minimum breaking strength of 3,000lbs. It’s easy to understand that why e track straps are not as strong as regular ratchet tie down straps, inside the box truck the loads already have strong support, at least there is no risk of falling off, all the e track straps will do is to fixate the loads more than tie them down.
In first paragraph we talked about design factor of ratchet tie downs, which is 3:1, so the working load limit is 1/3 of maximum breaking strength for ratchet straps, in the mean time the design factor of grade 70 tie down chains is 4:1, so the chains can support heavier load, and are more resistance to abuse, such as high/low temperature, moisture, while tie down straps usually only work well under normal condition. The standard material of which tie down webbing is made is nylon webbing or polyester webbing, depends on different tie down applications. The typical application for nylon webbing is motorcycle tie down, while polyester webbing is ideal for tying down concrete pipes. Following watch list is essential for making tie down webbing, abrasion, elongation, breaking strength and use environment. Breaking strength has to reach the recommendation level no matter what, and elongation has to meet the requirement, abrasion and environment sometimes are not that clear cut, when designing tie down we may have to consider the most extreme conditions these tie down straps may be in, or we may just consider the normal transportation environment.
