When purchasing a ratchet tie down strap, you will need to determine its working load limit. The working load limit is the maximum amount of weight that a piece of rigging can safely hold. This number is printed on the strap's tag. You should never use a strap without a working load limit, as it can pose a safety hazard to your personnel and cargo.

If you need to add a chain to your strap, you can use an industrial chain. Industrial chains can be connected to J hooks on ratchet straps to increase the strap's working load limit. They are also used to tie down heavy loads. These chains are often used to pull semi trailers.

Once you've determined the working load limit of your strap, you'll need to determine how to secure the strap. There are two main types of tie down assembly: full assembly and endless assembly. Each type of strap has a different attachment point. For endless assembly, one end of the strap is fed through a mandrel, and the other end is fitted with an end fitting. The strap then runs through the tie-down buckle to create tension. When tightening, the strap should overlap the other half of the strap on the other side of the ratchet.

Once you've determined the working and breaking load limits of your strap, you can determine which type of strap is best suited for your needs. For most applications, a full assembly is the best choice. The strap has two sections, with one end fitted with an end fitting and the other strap with a ratchet.