The ratchet straps are just the assemblies of ratchet buckle and tie down webbing, if we use cam buckle instead of ratchet buckle then it's cam buckle tie down, it's pretty straight forward, isn't it? Most likely these cam buckle straps are used on pick up trucks or passenger cars for luggage tie down, and small cam buckle(1'') are more popular than big ones(2''). 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, with 3,333LBS, 5,400LBS working load and a design factor of 3:1, these ratchets have 10,000LBS and 16,2000LBS breaking strength respectively, which are pretty strong for most tie down applications.
So far we discussed about tie down devices for flatbeds or similar transportation vehicles, we will see there are other kind of trucks, the typical one is box truck, and most of them have E Tracks installed inside the truck, for these rigs we use e track straps. In fact box truck has much bigger share than flatbed truck, the percentage maybe around 80%, of course this is only estimation but you get the idea, and the conclusion is that e tack straps are by far the most popular tie downs. With 1,000lbs safe load limit and 3,000lbs minimum breaking strength, e track straps are not as strong as flatbed tie down straps, It's understandable that e track straps have lower working load limit, because the box truck wall will provide strong support for the loads inside, and the truck wall will prevent the loads from falling off, rolling over, tilting and some other dangerous movements. Coupled with e track cargo bar, rope tie off, e track hardware(such as D ring with E fitting), shoring beam, e track tie downs can be used to secure any kind of loads, and secure them reliably, but you still have to pay close attention to the safety of your cargo, easy to secure is not an excuse for careless tie down practice.
We already discussed the design factor of ratchet straps, it is 3:1 and for the record all this says is that safe load limit of tie down straps is 1/3 of it's breaking strength, 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. When making the webbing, we have to take following characteristics in to consideration, the breaking strength, elongation, abrasion and the environment. There are mandated criteria for breaking strength and elongation of the tie down straps , while the abrasion and environment are mostly estimation and subjective sometimes, different area may have different requirements. Therefore the manufacturer may have to make these tie downs to different standards.
By Rudy Young