ShockStrap

Occasionally I meet a customer that assumes our ‘ShockStraps’ are made of rubber and I explain that ShockStraps are made with Urethane, not Rubber. In fact, urethane is just one of the reasons our customers are still using their Shockstraps after 10 years and more.

Rubber is biodegradable causing it to rot and degrade over time with exposure to the elements while Urethane is easily formulated to outlast rubber and stand up to sunlight and outdoor environments. I recently ran across a statement from Mearthane Products Corporation.

If you’re looking for superior abrasion, cut, and tear resistance, look beyond rubber to urethane. Urethane also boasts higher load-bearing capacity, better compression set, and superior tolerance to greases, oils, oxygen, and ozone.

Additionally, most cast urethanes like we use are available in grades that range from clear, to opaque, to amber making it easy to color. Interestingly, this ability to color urethane allows equipment manufacturers the opportunity to color code components like rollers and belts to simplify maintenance.

Finally, rubbers that are compounded to 90 or 95A durometer have compromised physical properties. Just the opposite is true of polyurethanes which maintain their properties and superior performance characteristics regardless of hardness.

Have you ever set your ratchet or cam buckle straps as tight as you possibly could only to find them loose when you stop and check them?  You knew the straps were tight before you hit the road.  You even put a cinch knot under the ratchet or cam and could tell that neither moved. Why do most strap manufacturers, on the back of their packaging, instruct their strap owners to pull over every 20 to 50 miles to check and retighten your straps?  Do they know something you don’t?

The simple answer is, “Yes they do.”

Although tie down webbing might look similar there are key differences between the three types of webbing material.  To determine which material works best for tie downs we will compare fiber stretch, UV protection, water resistance,  break strength, abrasion resistance, and overall safety.

Fiber Stretch

One of the reasons that tie downs become loose is that the webbing will stretch under a load. Polypropylene is a form of plastic and can stretch over 50% while under load.  Nylon tends to stretch between 20 to 30% under a 2500-pound load. Polyester stretches only 5 to 15%, making polyester webbing ideal for heavy loads.

UV Protection

Polyester is highly resistant to UV radiation which means it can stand more prolonged exposure to the sun than Nylon or Polypropylene without the material breaking down.

Water Resistance

Water can affect the strength and durability of tie down webbing materials.  Polypropylene and Polyester repel water and are more mildew resistant than Nylon which will absorb water.  Nylon webbing becomes much weaker when it is wet and will stretch when it is damp or wet. Polyester webbing can be wet and still be a very strong webbing for tie downs.

Break Strength

The break strength of a webbing material is the maximum stress or load that can be applied to the fabric before failure or it breaks. Polypropylene has a break strength of 700 pounds, Nylon is 2,500 to 7,000 pounds and Polyester is 2,000 to 10,000 pounds.

Abrasion Resistance

Tie down webbing that resists abrasion is extremely important in securing your load.  Even seemingly minor webbing damage can significantly reduce the capacity of a tie down to hold objects and increase the chance that the tie down will fail during use.  Polyester webbing is more resistant to abrasion than Nylon or Polypropylene.

Overall Safety

Keeping your load safe and secure is extremely important.  A tie down must be able to withstand UV radiation, water, and abrasion as well as have a high break strength and a minimal amount of fiber stretch.    Using stretchy tie down webbing can cause damage because the stretchy strap lacks the tension needed to keep the load secure.  Abraded webbing can increase the chance that the tie down will fail.  When comparing overall safety of tie down materials, Polyester webbing is the clear winner.

The Clear Choice

Polyester webbing is the best material for your tie down straps.  Its resistance against abrasion, UV rays, and water make it a better choice for tie-downs than other webbing materials.   It is also mildew resistant which makes it an excellent option for snowmobiles and watercraft.   The combination of strength and resistance to stretching and abrasion make it ideal for a strong durable tie-down strap.

Bottom Line

Polyester is more expensive than nylon and this is why most tie-down companies have switched to lower quality nylon for their webbing.  ShockStraps use 3,800 pound polyester webbing instead of lower cost nylon so our ShockStrap, and not our webbing, does all the stretching.  It’s the reason we don’t have customers calling us to say our hooks are coming off of their load or that their straps are coming loose when traveling down the road.

We all have pulled over to check our tie downs only to find them loose or missing.  Most tie down manufacturers state on their packaging that the load should be checked every 20 to 50 miles.

Image of Competitor Strap Instructions, see the 7^th bullet.

Under the movement of your load the webbing can stretch and become loose or pop off.  Because your tie downs are always under tension, when you drive over a speed bump or a pothole on a road several things can contribute to your tie down becoming loose or flying off.

The springs on your equipment, trailer and vehicle all flex when you hit a bump and with a tight tie down something has to give and that often is your tie down.  What happens is your webbing will flex causing slack and when your load shifts, it stretches the strap further.  Or worse, the hooks pop off and your strap is left on the side of the road. (this is why you see straps in the street).

Even when you tie below your shocks or springs on your UTV or ATV you are still dealing with the air pressure of your tires which are typically under 5lbs of pressure and act like a giant marshmallow, compressing and flexing over every bump.  This can cause the strap to start to stretch or pop off.

ShockStraps are different.  Our tie downs use high quality polyester webbing and have a built in ShockStrap in the tie down.  We do not need to tell you to pull over every 20 to 50 miles or at any time to check your load.  All we ask is that you stretch the ShockStrap to over ½ inch or more to engage them.  Your load is now secure for the duration of your trip.