There has always been a debate amongst cargo haulers on how exactly to strap down their load. It does not make a difference if you are using a one-inch-wide strap that has a workload limit capacity of 400 pounds or a four-inch-wide strap that has a workload limit of five and a half thousand pounds. Ratchet straps and heavy-duty winch straps all serve the same purpose and that is to keep your cargo safe and secure during transit. But the only question is should you twist the cargo strap before you anchor down the load or not?
Feel free to do your research and you will find various opinions from veteran truck drivers as to how they secure their loads. In this article we are not going to claim the validity of one side of the argument, rather we are just bringing you accurate findings allowing you to make a judgment before you make your next haul.
Why Do Flatbed Truck Drivers Twist Their Straps?
Ever drive next to a long flatbed rig and notice the straps securing the load? The truck can be carrying anything from bags of cement to tall sheets of glass. There is alway one objective, to complete the safe transport of goods from one point to another. In order to secure the load the driver will ensure that there is a strong cargo strap pulled over the goods at a point that can provide optimal securement. While the operator ties down the load they will often twist the strap which makes it appear to the outsider as a little sloppy. But in truth there is a really important reason why these drivers choose to twist the cargo straps.
Understanding The Physics of a Flatbed Truck Cargo Hauling
Wind plays a very important role when auto and truck manufacturers design their vehicles. Car manufacturers will run a wind tunnel test to see how the car performs when being placed in front of a wind turbine. What the maker is looking for is to see how well the wind deflects off of the car to avoid any effect in its performance. If the wind were to slow down the car that would mean more energy will be needed resulting in greater fuel or electricity usage. That is why the aerodynamic design of the vehicle is vital to how it will or will not deflect the wind that can impact the car's overall performance.
As per flatbed trucks they are not so lucky and have not had the luxury of being manufactured to be aerodynamic. The length of the flatbed trailer is anywhere from forty-eight to fifty-three feet and that is just for one hitch. Very often these trailers can haul tandem flatbeds depending on the length of the load. This all means that the flatbed chassis is exposed to wind on all sides and the operator must take that into account when securing the load. Even after the load is safely anchored down to the flatbed the cargo straps create their own wind tunnel test due to the gap that is left based on the tie down angle. A truck that is driving seventy to eighty miles an hour will have an intense air flow that makes even the strongest cargo straps susceptible to shaking. If the straps shake that means the load might get moved around which compromises the securement and more importantly the safety of the truck driver and the other drivers on the road. Just imagine if it is a windy day outside and which makes things worse. Doing cargo securement right is not just important for the integrity of transporting the goods but most important is the safety of all on the road, including the truck operator in the cab. All too often improper cargo securement can result in bad accidents on highways and roads.
So What Does The Twist In The Strap Do Anyway?
When cargo straps are twisted on either side of the load, they will in essence become aerodynamic and that allows the air to deflect and reduce strap shaking. Similar to the way a frame or an automobile is shaped to deflect the wind, the twist will create a similar format that allows the air to pass through without impacting the tension of the strap that is anchoring down the load to the flatbed. Though it may look odd to someone passing by the twist is actually very thought out and helps keep the load safe and secure.
It does not matter the truck speed, wind intensity, or size of the load, as the air hits the straps it will deflect keeping them in place as originally secured by the flatbed operator. Just be careful as to how many twists you use so as not to diminish the workload capacity too much. There are some that claim that with every twist the strap loses its strength, but this myth has been debunked in our last article. In general, with cargo securement, it is always good to exercise caution on behalf of the load, the operator, and the other drivers on the road.
When flat cargo straps are twisted, they will act similar to the way the wind bounces off a blade of grass. Things can get screechy and noisy with flat straps and the twist disrupts the airflow and avoids the horrible noise. It also keeps the strap from slapping against what you're hauling to prevent damage to the item.
Wind Causing Strap Vibrations Truly Depends On The Load Height
Why do tall loads tend to be more susceptible to wind? To give you an example, think of how a skyscraper is built and how it is made to deflect the wind. The Twin Towers of blessed memory were ingeniously designed with three thirty-foot steel beams that were welded together to create a relatively lightweight panel. The buildings would have to be able to sustain hurricane force winds and these creative columns would be the secret to reflecting and absorbing the wind keeping the buildings strong and secure. With a tall building, engineers must be cognizant of an increased wind factor and the same is with a load that rests on a flatbed truck. The taller the load the more susceptible are the straps to shake and loosen.
Once we understand the physics of how the wind affects taller loads it is safe to say that it would be fine for shorter loads to go twistless. Open trailers that anchor straps straight across may experience little to no strap vibrations due to a very small area for the wind to pass through between the strap and the cargo. In such a scenario the wind is more likely to deflect then send vibrations up and down the winch straps. Of course, it goes without saying that any load needs to be battened down properly for safe transportation. It’s not uncommon to pass a flatbed trailer on the road and see the winch straps offline which can make the cargo vulnerable to shifting during transport. Experienced cargo haulers will be around when pallets are set to ensure that they are properly aligned with the winches just in case they are welded on to the trailer and don’t slide.
What Is Considered a Tall Load That Would Require Twists?
One veteran driver said that only a load of eight feet or higher would require twists, anything less than that would not. It does not matter how windy it is outside or the weather conditions. When a winch strap is properly set from one side of the trailer to the other it should not vibrate or make noise.
This may be the case when we are talking about multiple four inch by thirty-foot winch straps that are setup from the front to the back of the flatbed trailer. However, if we were to place a wheelbarrow on top of the roof of a Ford pickup truck the driver will experience a loud vibrating noise from the ratchet straps. In this case there was a Stanley 100 Liter poly wheelbarrow with an estimated height of not more than 30 inches. The solution to prevent the strap vibrations was a half a twist on either side. So, is there a cap height of eight feet where we can be certain that twisting is not required?
Theory of Cargo Height Relativity
You don’t have to be Albert Einstein to understand that the height of your cargo is relative to the base it is strapped to. When we are dealing with a forty-eight-to-fifty-three-foot flatbed trailer that can hold anywhere from 46,000 - 48,000 pounds, the load height starts from the bed. As opposed to a Ford pickup truck the load height would begin from the road where the actual vehicle rests. Since that is the case, the average height of a typical Ford F150 is a little over six and a half feet. Place a wheelbarrow atop a rack and you are well over eight feet. In such a scenario the strap would be exposed to the wind just enough to create a noisy vibration that would require a twist.
Understanding where the height of your load starts is an important factor when it comes to placing a twist in your strap to prevent vibrations. The theory of cargo relativity is nice, but it would be of no relevance when you as the driver are transporting a load and begin to hear a loud vibrating sound. At that point a simple half twist on both sides of the strap will be the antidote to the noise.
Final Thoughts
The question of “To Twist or Not to Twist Cargo Straps?” will be forever debated by flatbed drivers. Each will have his or her opinion based on their driving experience. Taller loads are more susceptible to wind vortexes being created that can potentially lead to straps vibrating. At that point the cargo can become vulnerable to shifting if the trailer shakes due to a bump in the road. The solution in such a scenario would be to make sure that there is a half a twist on either side of the load. The twist makes the strap aerodynamic and allows the wind to pass through with little to no vibrations. Naturally a shorter load will be less likely to be impacted by the wind and straight over straps should suffice to keep your straps from vibrating. But always keep in mind that shorter is all relative to where we start counting the height from, according to the theory of cargo height relativity. But what is most important is that you are the driver and whatever judgment you make to keep your cargo safe is most likely the right one.
