Voodoo, It's Science

Tie-Down Straps: It’s Not Voodoo, It’s Science


I was perusing one of my favorite online magazines when I ran across a brief review of a particular brand of cam strap. The author spoke of this brand’s ‘voodoo’ that makes their straps tighter than the competition. Then I got to thinking – it’s not voodoo, it’s science.

I understand the author’s point. He used the term ‘voodoo’ to explain that this particular brand, Rollercam, made use of a patented design that competitors aren’t using. The design ostensibly makes their cam straps easier to use. You get more pulling force with less effort. Hang tight and I will explain how and why.

Cam Straps in General

The whole idea of using cam straps as tie-downs is based on well-known science. A cam strap is a webbing strap with a cam buckle on one end. You thread the loose end of the strap through the cam buckle and pull firmly. Meanwhile, a toothed plate digs into the webbing material and holds it tightly until the release button is pushed.

Looking at cam straps from a scientific standpoint is fascinating. A combination of force and friction succeeds in keeping the strap in place. But there is even more science involved. Imagine running three or four cam straps across the top of a load of furniture in the back of a pickup truck.

What keeps the furniture from moving? Downward force and friction. Each of the straps creates friction as it contacts the furniture underneath. The tighter each strap is pulled, the more downward force it creates. This increases friction between both furniture and strap and furniture and bed truck. Increased friction keeps everything in place.

Rollercam Voodoo

As for the particular voodoo the author mentioned in his article, it has to do with Rollercam’s cam buckle. Most competitors utilize a stationary cam over which the strap glides as you pull it through the buckle. The cam is more or less a metal cylinder. Webbing material slides over it easily enough.

In Rollercam’s design, the cam actually rotates in place. How does this help? It reduces friction as you’re pulling the strap through the buckle. The end result is that you’re not fighting the cam and the plate at the same time. You can pull the strap tighter with very little force.

Another advantage of the cam strap is that you can be more precise about how tightly you deploy it. Ratchet straps are pretty strong in their own right, but you have less flexibility in terms of tightness because ratchets are unforgiving. There is always the possibility with ratchet straps of having to tie something down too tightly or leave it too loose.

We Take the Science for Granted

To me, the science behind tie-down straps is fascinating. I suspect that I am unusual. I suspect that the science behind how it all works is taken for granted by most people. That’s fine. As long as a tie-down strap performs as intended, that’s all that really matters. Whether a person is hauling toys, moving to a new house, or transporting cargo across the country, the science of it all is less important than the fact that tie-downs work.

The one thing I can say is that there is nothing about tie-down straps that would constitute voodoo or magic. The people who design cam and ratchet straps put a lot of thought into them. They know the science behind tying things down. They engineer their products accordingly.

If you are interested in experiencing Rollercam voodoo for yourself, the reviewer says their cam straps are pretty affordable. Otherwise, there are other brands to look at.

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