A strap is a strap...

[evilfij]

My experience in mud is that the stretch hurts more than helps. Thing of it like a wrench on a bolt. If you just keep adding force it will not turn, but a shock load frees it up so to with a decent jerk from a non-stretching strap.

IMHO of course.

 

[scottishpinz]

I've got quite worried reading this thread that people do not understand the different types of straps, their uses and safety.

A kinetic recovery rope KERR or strap! is designed to stretch, storing its energy like a giant elastic band, the energy released is far greater than that which would be exerted by a tow with chain or static rope. When all components are correctly rated, and used correctly it allows even a fairly light vehicle to exert enough force to free another stuck vehicle.

A stretchy rope is not a recovery rope!! It will appear to do the same thing but cannot safely handle the forces involved and could fail with fatal results. Some tow (not recovery) straps or ropes are designed to stretch a bit to avoid shock loading tow points and make for a smoother tow. Even if these were rated say 5 tonnes and towing a 2 tonne truck they would be overloaded if used for snatch recovery!!

Static ropes and straps are just that. designed for steady pulls or lifting. They are not designed to be shock loaded. Shock loading a static rope could easily cause it to fail with fatal results.

If you do not know what sort of straps you have you should throw them away! Using them incorrectly might be the last thing you ever do!

 

[JamesDowning]

Extremely intuitive.

The tree savers are very short, the straps nominal length and the winch extension extremely long.

(if that isn't easy enough the white label sewn to the strap does indicate which it is )

I have a mixture of ARB and non-brand straps. To unify it myself, I used a sharpie to put a S (for static) or D (for dynamic) on all of my straps... just in-case the white label gets torn off. I also list the WLL in big numbers on the ends. They do something similar with high-angle-rescue gear, but they have a little different system (tick marks).

My experience in mud is that the stretch hurts more than helps. Thing of it like a wrench on a bolt. If you just keep adding force it will not turn, but a shock load frees it up so to with a decent jerk from a non-stretching strap.

IMHO of course.

The issue isn't so much effectiveness, it's safety. Impulse loading a static strap is plain dangerous. Bouncing off a strap with a 5000 lb vehicle generates enormous impulse forces in the strap, the recovery hardware, and vehicle.

This is an excerpt from a writeup I did on another website... you may glaze over the math part, but at least look at the resulting numbers. Using a stretchy strap gives you a lower force, but it lasts a longer duration, and it's within a safe working range of your other equipment.

Keep in mind that the numbers below are based solely upon the situation laid out and will not exactly duplicate real world situations.

We’ll use an average 5,000 lb vehicle as our example recovering vehicle. The two vehicles are attached with the strap, loose at first. The recovering vehicle proceeds forward with a bit of gas, reaching only 5 mph when reaching the end of the strap. At this point the vehicle has gathered kinetic energy equal to 1/2*mass*velocity^2.

KE = 0.5 * 5000 lb * (5 mi/hr)^2 = 5.7 kJ

We will assume for this instance that the stuck vehicle will remain stuck and will not budge (worst case)… so all of the recovering vehicle’s energy transfers into the strap and is turned into elastic potential energy. This stored energy will be equal to the kinetic energy that the truck had. This stored energy relates to the force exerted on each end by the following: energy = average force * distance. The distance is how far the strap stretches. The average force is assuming the rope exerts constant force, which ours does not. Because it’s force exerted most closely resembles a linear relationship to the stretch, the average force should be multiplied by 2 to get the maximum exerted force (which is all we are interested in here)… assuming the system reaches equilibrium without failure.

In instance 1, we will use a dynamic strap, which can stretch about 6 feet.

5.7 kJ / (6 ft) * 2 = 2,089 lbf (well within the safe range of most straps)

For instance 2, we used a static strap, which we will assume stretches only 4 inches before reaching equilibrium.

5.7 kJ / (4 in) * 2 = 25,072 lbf (enough to snap a strap or possibly rack your frame)

For the last instance, what if we used a chain, which has extremely minimal stretch. So we will say 0.5″…

5.7 kJ / (0.5 in) * 2 = 200,576 lbf (you will certainly break something!!)

So, I hope this gives you a real world, numerical understanding of why dynamic straps should ALWAYS be used in dynamic vehicle-to-vehicle recoveries.

* I did not show unit conversions for the sake of simplicity (there were a lot)

 

[ntsqd]

James,
Nicely done.

 

[MattGuyver]

I own both- the ARB is for me and my fellow overlanders and the Farm strap is the one I loan out when I'm approached by the ill-prepared. (The same type of folk I see using a chainsaw as if it's a Ditch Witch.)

 

[Jean-Seb]

Great thread, thanks for the info.

 

[Donsfast]

I have a really nice high dollar snatch strap I keep with me and a cheapy snatch that I keep as well for when you think you might tear a strap with rocks, etc. I must admit I use the cheapy endlessly compared to the high dollar still new appearing strap. It kills me to beat up a $100 strap but of course it makes perfect sense to use the heck out of the $30 strap all day. :gunt:



I always wanted to use that guy!

 

[timmer2008]

the good stuff is proof tested and accuratly rated

 

[sjk99]

Bulldog has a destructive comparison test on their site. The purpose was to verify package breaking strength claims:

http://bulldogwinch.com/straps.html

Of course they show their product passed but a couple others did as well. And for that matter, even for the ones that failed you get an idea of what their capacity is.

Someone mentioned paying $100 for an ARB strap. Search for "recovery strap" on Amazon and the ARB 3 1/4" is $83 (if it matters.) Amazon lists numerous other brands. As mentioned earlier in the thread, some of these are advertised as "tow straps" and some are "recovery straps" and some are listed as both. Probably want to stick to name brand recovery straps (unless you want a tow strap.)

 

[michaelgroves]

While it's important to buy a good quality strap, especially the kinetic type, just remember that the strap breaking is not particularly dangerous, if you are following reasonable safety practices.

What is potentially lethal is the strap not breaking, and the huge forces launching your towing eye, receiver hitch, bumper mountings or other sundry lumps of metal into low orbit.

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)!

Of course, as we've discussed on this forum before, the inherent problem is that it's impossible to judge reliably how much force you are putting on the strap when you are doing a kinetic recovery. Therefore, I would prefer to err towards having a strap with good stretch but a lower ultimate breaking strength (relative to all the other rigging and mounting points being used).

I think it would be useful for manufacturers to print the maximum breaking strength onto their kinetic straps!

 

[I Leak Oil]

This thread has got me thinking(hence the smoke coming out my ears). There is a time and place to buy the best, but my thoughts on items like straps are different. Does anyone else consider it a consumable item?

These do wear out eventually so why buy the best at 5 times the price for only twice as much life? I don't have any offroad name brand straps but I do have a Keeper, as well as quality rigging and lifting straps. Not top dollar off road branded but have worked non the less.

 

[sjk99]

I think it would be useful for manufacturers to print the maximum breaking strength onto their kinetic straps!

While we wouldn't really know what bit would break - bumper, frame, hooks, shackle, strap, etc., it might be useful to be able to dial-in a pre-determined not-to-exceed load and use one of these things:

http://www.massload.com/product-Tension_Link_Dynamometer-7-2.html

as the sensor to trigger something like the rev-limiter in the vehicles cpu and shut off the engine.

 

[YJake]

There is a time and place to buy the best, but my thoughts on items like straps are different. Does anyone else consider it a consumable item?
Not really, I rarely use recovery straps but maybe once or twice a year. With use like that I imagine the lifespan of an ARB strap would rival that of myself. That is, unless I drag it over a rock or through mud/water every use and never clean it.

I don't have any offroad name brand straps but I do have a Keeper, as well as quality rigging and lifting straps. Not top dollar off road branded but have worked non the less.
I don't own any high end straps either. However, I do agree that the straps I own have worked just fine the two times that I've needed them. My straps are simply stretchy straps used to lift things by use of a crane.

The way I see it, other straps will work just fine but I'd like to buy an ARB or Viking Snatch Strap because I know that it'll last a very long time and work when I really need it to. That my freind is the peace of mind I require while out Exploring. For any other trip into the woods for "wheeling" or "testing" the off road capabilities of my vehicle with others the cheaper straps don't bother me at all, because the closest gas station is a 15 minute trip down the black top.

Being 2hrs from nowhere and stuck however is not the time to find out that your free/cheap recovery strap is not up to par for the situation.

Just my thoughts is all. :ylsmoke:

-Jake

 

[michaelgroves]

While we wouldn't really know what bit would break - bumper, frame, hooks, shackle, strap, etc., it might be useful to be able to dial-in a pre-determined not-to-exceed load and use one of these things:

http://www.massload.com/product-Tension_Link_Dynamometer-7-2.html

as the sensor to trigger something like the rev-limiter in the vehicles cpu and shut off the engine.

Nice idea! However, the snag is that a kinetic recovery uses the momentum of the vehicle to impart the force, so there's nothing to measure until it's too late!

 

[R_Lefebvre]

Interesting website from Bulldog. I'm assuming brand "E" is Erikson, typical farm store brand, and what I'm using. I think the testing actually had the opposite effect on me. I think the strap I have is "strong enough" for what I need. It's close enough to the package claims.

25,000lbs breaking strength will mean more than 4g of acceleration on my truck. That's a hell of a yank! Also of note, the cheap white Erikson strap actually has a higher breaking strength than the lower rated but more expensive ARB. Moral of the story, if you are conservative with your loading and weight ratings, the cheap ones should be fine.