This has been a long going discussion with drivers. This is also a topic that I have witnessed first hand give major grief to many a driver when the rub rail failed. The decision is yours to make, but there are good reasons NOT to route tie-downs on the outside of the rub rails or attach them to the rub rails:
- If your chains or straps are located outside the rub rails and you rub the trailer against a wall, barricade, or another object, your tie-downs — and not the rub rails — could take the brunt of the impact. And it goes without saying that damaged tie-downs are dangerous, potentially leading to an out-of-service vehicle, damaged cargo, and/or a serious accident.
- Rub rails are normally designed to protect tie-downs, not support them. In fact, most rub rails are not rated by the manufacturer for cargo securement purposes. Given the abuse many rub rails are subject to, they may not be strong enough to serve as anchor points, especially when constructed of aluminum which can bend and crack easily. Stake pockets are a better choice for securing tie-downs.
- I have even seen overwidth violations because the chains and binders were outside of the width of the trailer. Overwidth is overwidth.
- I have watcher loaders hit the rub
rail, and do damage to chains and straps during the loading process. Again, this is why the rub rail is there, to protect your cargo securement devices.
Of course, there are times when you have no other choice but to route tie-downs outside the rub rails or attach them directly to the rub rails. Drivers must use their best judgment when determining how best to route and attach tie-downs. But they should always keep the risks in mind: tie-downs routed outside the rails could become damaged, and rub rails to which tie-downs are attached could fail.
There are many resources out there to learn about cargo securement. Here is one link that I think really gives a good understanding of the whole process. I am not endorsing this link but I do feel that you may learn a thing or two.