A strap is a strap...

[JamesDowning]

It's a Catch 22 - you want the strap to stretch properly so as to be less likely to shock-load whatever it's attached to, but if something hard or heavy does break, you want the rope to have stretched as little as possible (as each centimetre of stretch is more stored energy)!

If you're dealing with a static load, you'd be right. But we're dealing with energy of motion. No matter the amount of stretch the strap has you've got the same amount of energy going into the strap (all the energy is from the vehicle speed and mass). That's why more stretch is safer in this situation - it reduces the forces that occur in the strap so you can "bounce" off it without breaking stuff.

But you're right if you're talking about using a dynamic strap in a static situation (like with a winch as an extension). Instead of moving the vehicle with the winch's energy, you're just storing energy in the strap initially.

 

[michaelgroves]

If you're dealing with a static load, you'd be right. But we're dealing with energy of motion. No matter the amount of stretch the strap has you've got the same amount of energy going into the strap (all the energy is from the vehicle speed and mass). That's why more stretch is safer in this situation - it reduces the forces that occur in the strap so you can "bounce" off it without breaking stuff.

You're quite right - other things being equal, a stretchy rope will launch a broken shackle at the same energy, whether it's stretchy or super-stretchy. There is one difference, though - you're forgetting that the vehicle is being powered forward. I think in practice this means that a more gradual stretch will impart few hundred kW.s of extra energy to the rope.

 

[R_Lefebvre]

Yes, if you're talking about power stretching the strap, a "softer" stretchier strap will store more energy than a harder strap. However, it also likely has more hysterisis, so you won't get all that energy back on release.

 

[timmer2008]

So this was the answer I came up with:

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the stiching on the viking strap looks AOK . I also like the fact that it is Made in USA

personally I use a 7/8" yanker rope and a red proof tested round strap with a basket rating of 26.4K#

 

[freeze]

Here's something from CT4WD.com

Here's a little bit of information regarding Recovery Straps as it is one of the most common piece of recovery gear on the trail besides a Bow Shackle.

A recovery strap is made to have elongation built into it. This is the amount of stretch that is allowed to occur to help with a recovery by keeping it gentle and create kinetic energy. There is approx. 15% elongation in a recovery strap.

You want to make sure the strap you're looking for is not built for hoisting as hoist straps do not have any elongation built into them.

It is important to also have loops or eyes on the end of the strap and no hooks. At this area it's important to not the loops are stitched lengthwise on itself and not criss crossed. This is important for strength as the criss cross style of stitching if threads pull out, it'll rip apart very quickly.

These loops are where you would attached a Bow Shackle to and attach it to a solid closed loop frame mounted recovery point.

When it comes to how strong of a strap, typically for our Toyota's a 2" wide strap which is rated for (vehicle 1 + vehicle 2) x 1.5 = Minimum Breaking Strength.

For Example:

Toyota 1 = 5,000 LBS

Toyota 2 = 4,000 LBS

(5000 + 4000) x 1.5 = 13,500 LBS

So a 14,000LBS rated strap which is 2" wide will work just fine, however, if you're intending to pull bigger trucks then you may want to look at a slightly larger strap. It doesn't hurt to have two one for our Toyota's and another for a full size!

Do not leave your strap where the sun can get to it as they are not UV protected and they will become damaged. Some straps have a stripe down the middle for this exact reason.

Do clean with water and mild soap and hang dry.

You'll learn quite a bit more in the courses but this is incase some of you were looking to get a strap in the future.

Inspect your strap for frays, holes, or loose stitching. Replace when these are visible.

Do you remember how far one must stand from any recovery taking place? (If you've taken the course let the other people have a chance to answer this one!)

- Nathan (freeze)
http://www.ct4wd.com/forum/showthread.php?t=1961