Ratchet Webbing Tie Down: Nylon and Polyester Webbing
Thursday, March 31st, 2011The ratchet straps or sometimes just called ratchets are what we get when we assemble ratchet buckles and tie down webbing, with hooks at both ends , by this logic the cam buckle strap is just the cam buckle with tie down strap, why I am not surprised? Due the low strength of the cam buckle, we usually see these cam buckle tie downs being used on pick up trucks, 1” cams are all over the place while 2” cams are being used in box trucks. Unlike cam buckle, ratchet buckle are much stronger, and 2”,3” and 4” ratchet buckles are used in industrial grade applications, such as heavy duty transportation, 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 commercial vehicles, there are another kind of ratchet straps for semi trailers, ratchet e track accessories , these tie down equipment will be used with E Tracks installed inside the semi trailer. In fact semi trailer 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 working load limit and 3,000lbs minimum breaking strength, e track tie downs 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.
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, for comparison purpose we know that the binder chain has a design factor of 4:1, which basically says that for the chains the working load limit will be 1/4 of their breaking strength, which indicates that tie down chains are designed for tougher environment than tie down straps are in. 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. When making tie down straps , manufacturer has to follow the recommendation of breaking strength and elongation requirements, when it comes to abrasion and environment, there are much more variations to be considered.










