Weakest point in winch and rigging?

[jcbrandon]

Ideally, where would the weakest point in your complete winch and rigging system be, if you could intentionally put it anywhere?

Think of a fuse. The weakest point of a system designed to fail first with the least amount of damage. Also, ideally, easy to replace.

I ask because I recently bought a truck with a Warn 12,000-pound winch installed. I'm learning everything I can with an emphasis on separating hearsay and anecdotes from facts. Prior to posting this question I searched the ExPo forum for the words "winch" and "cable" and read some great stuff. Thank you to all who have contributed to previous threads, especially this one on "synthetic winch line (http://www.expeditionportal.com/forum/showthread.php?t=12882&highlight=winch+cable)."

The winch came with 90 feet of 7/16" wire rope. I'm having difficulty determining the safe working load and breaking strength of that wire rope.

I also bought a snatch block (Warn part number PN 15640) rated at 24,000 pounds. I was more than a bit dismayed when I opened the box to discover cast into the side of the housing "WLL 4 1/2 Ton." So my 24,000-pound block is only rated for a safe working load of 9,000 pounds, yet the manufacturer recommends it for use with a 12,000-pound winch.

So trying to make sense of all this brings me to the fuse question. And that leads me to wonder exactly what would happen if I put 12,000 pounds of stress on this winch. Would it just stall and quit? Overheat and burn out the motor? Would something break?

If I beef up one part of the rigging, will that have unintended consequences? Would I transfer the weak point to somewhere I don't want it to be?

[AndrewP]

WLL ratings are for overhead lifts, and typically 4X breaking strength. That snatch block sounds fine.

7/16 cable is big stuff and typically a 12000lb winch will come with 3/8 cable.

I would not intentionally build a "fuse" into anything that comes under load. I did think the shear pin in the old Toyota PTO winches was a decent idea-it was designed to shear before the cable broke. If you really plan to pull that hard, watch what you connect to carefully.

Most extraction pulls offroad are in the 3000-4000 pound range, unless pulling a huge truck out of deep mud, or a completely dead tuck up a difficult spot.

[ntsqd]

I've also noticed what Andrew touched on, that self extraction components regularly exceed the WLL of equivalent industrial rigging by a large margin. Apparently OSHA has no say in self-extraction. Anything that lifts or supports humans, or lifts something potentially lethal above humans, usually has to have a Factor of Safety of at least 4 and sometimes 5. So at best a 5000 lbs tensile strength wire rope could only "legally" lift 1250 lbs.

I guess my concern over a fuse in the system would be what happens if the fuse blows? Does the cable go slack? That would be a major bad thing.
If all of the equipment and anchor points are equal to or exceed the strength of the winch, then the 'fuse' would be stalling the winch motor. I see that as the most ideal set-up.

FWIW, Sampson (http://www.samsonrope.com/index.cfm?rope=192) lists their Amsteel Blue in 7/16" as having an average breaking strength of 23,900 lbs.
Wire Co. (http://www.wrca.com/wr_78strand.html) lists one of their 7/16" wire ropes as having a average breaking strength of 15,600 lbs.

[mog]

If all of the equipment and anchor points are equal to or exceed the strength of the winch, then the 'fuse' would be stalling the winch motor. I see that as the most ideal set-up.

A +1 with ntsqd. If everything, cable, blocks, anchor points (both on and off the vehicle) exceed the winch's rate, it should stall out prior to anything letting go. Probably the most desirable effect, since you still should have tension, nothing 'letting go', so only a "dang, I need more power". And with a 12,000 winch plus a snatch block, I would hope you should be good to go.

[IggyB]

IMHO the weakest link wouldbe the cable itself. 3/8" cable is rated at 12000 lb nominal strength. That's the only rating it has, there is no 4:1 safety margin.

So if you take brand new 3/8 rope as good for 12000 lb,
once you wrap in on a 4" diameter winch drum it's detated a certain amount,
once it's used and has a kink or two or has been pinched it's derated again.

So after a short while the rope is weaker than the winch.

[ntsqd]

The problem there is when the 'fuse' blows you have a very, very dangerous condition. One to be avoided at all costs. I have seen pictures of the aftermath of a snapped cable. It is not pretty and can be very deadly.

If you opt for one of the poly ropes the severity of a snapped rope drops significantly, but what then happens to the vehicle that was being pulled by the winch?

[Bill Beers]

And that leads me to wonder exactly what would happen if I put 12,000 pounds of stress on this winch. Would it just stall and quit?

It will still reel in cable w/a 12000 pound load attached. Keep adding load over the 12k and and eventually the winch will stall. Warn winches are very tough. Heck, the 9.5 XP will pull 12k.


Overheat and burn out the motor?

If you keep trying to winch after it's stalled, you'll mess up the motor. If you keep winching after your motor gets too hot, (which can/will happen at less than the rated load,) you'll mess up your motor. The new Powerplant winches have a thermal load cut off switch that will protect your motor from heat damage.


Would something break?

Eventually, I suppose the cable would break. Or if you have a crappy bumper, it could rip off.

The worst case I could think of is a dead truck in the mud, there you have suction working against you and nothing working for you. If the truck is still driving, that takes load off the cable.

-Bill

[madizell]

The safety fuse in a self-recovery system should be the guy with his thumb on the switch. Motor overheating? Wait 5 minutes and try again, or go double line pull. Motor stalled? Double line. Motor stalled while pulling double line? Yikes. Assuming that all electrical components of the system are at least rated for the system, and the alternator and battery are at full capacity and will support the demands of a 12,000 pound winch, stop winching and find another solution. Triple up the line if equipment is available. Dig out the axles, frame or whatever. Remove large obstacles from in front of the axles. Reset the line of pull to reduce or eliminate angles. Get more than one truck in on the pull.

I have seen 12,000 pound winches stalled lots of times, but only when they were not working to full capacity or did not have enough electrical or hydraulic support. A truly good and correctly working 12,000 pound winch will pull an enormous load, and on a standard truck, can bend or break frame components, especially if not hooked up correctly. I have tweaked the frame on my CJ-7 with only an 8,000 pound winch by pulling more than I should, off angle (diagonal stress). Better not to use the full capacity of such a winch unless you are pulling on a 2-ton utility truck, which is to say you should not see the winch stall under normal self-recovery scenarios.

Best not to have the line break, no matter what. Especially with something as heavy as 7/16 steel line. It could get ugly.

[jcbrandon]

Thanks, ya'll; I appreciate your insight.

The winch on my truck does have a thermal protection circuit. So it seems that is along the lines of my thinking on building in a sort of "fuse". If I try to exceed the capacity of the system, the winch will just decide to take a rest. No harm, very little danger, and maybe while it cools down I'll rethink my rigging set up.

It appears that the next weakest point in the system is the cable. If it fails, things can go very bad. But all things considered, if something is going to break, the winch cable might be the least evil.

I'm considering upgrading to a synthetic cable. This will almost certainly be stronger than the existing steel. Since the current wire rope might be over-designed, I could probably gain extra winch line length by going to a smaller diameter synthetic which would still be stronger than the existing steel.

Sounds like I'm good to go. Unless I've overlooked something...

[Michael Slade]

The weakest link in any winching scenario is always the operator/rigger. The equipment is only as good as the knowledge that was used to set it up. Know the gear.

The moment you forget that your equipment can kill you, it will.

[madizell]

The winch on my truck does have a thermal protection circuit. So it seems that is along the lines of my thinking on building in a sort of "fuse". If I try to exceed the capacity of the system, the winch will just decide to take a rest. No harm, very little danger, and maybe while it cools down I'll rethink my rigging set up.

It appears that the next weakest point in the system is the cable. If it fails, things can go very bad. But all things considered, if something is going to break, the winch cable might be the least evil.

I'm considering upgrading to a synthetic cable. This will almost certainly be stronger than the existing steel. Since the current wire rope might be over-designed, I could probably gain extra winch line length by going to a smaller diameter synthetic which would still be stronger than the existing steel.

Sounds like I'm good to go. Unless I've overlooked something...

A thermal over-ride is not a safety fuse. It only protects the motor internals from excess heat. Lots of things can go wrong before the motor heats up, if it ever does. Try not to make assumptions based on the presence of a thermal cut-off. Generally, a thermal cut-off will operate when you are making long, continuous pulls within the working range of the winch, but outside the duty cycle of the motor. You will more likely break a cable or rope early on in a recovery while the winch is operating with a cool motor.

A broken cable is not the least evil a winch can sustain. Low batteries can be charged, connections restored, bolts replaced, jammed cable can be unjammed, solenoids can be replaced in the field, and so on. Cable, on the other hand, is dangerous when loaded, and in order to break, has to be loaded to the breaking point. Steel cable is heavy and stores energy, and when it breaks, it has lots of sharp little teeth that slash around without warning. This is why you should never be anywhere near the cable or the line of pull when winching.

It is also quite difficult to field repair cable or rope, either one. I have yet to see a successful field repair of rope by tying a knot, and cable can't be spliced or knotted, and clamps in line are not safe or adequate. Once broken, it seems that neither rope nor cable are long enough to do the job anymore. Best to carry a spare if you think breakage is possible. Cable is not especially expensive, but is heavy; rope is not heavy but is especially expensive, and has to be spliced to a hook to work at all.

The strain rating of rope versus cable suggests at a glance that rope is stronger. This is rarely the case, however. Both break in the field for a variety of reasons. Rope is not resistant to abrasion or to sharp edges, and loses strength when bent around a fairlead. Assume rope to have only 50% of its rated strength and you will be in the ball park, and such an assumption will put you right back down there with equivalent steel line.

Rope will usually give you more length to work with, but this is not always an advantage. All winches are rated for maximum pull on the first wrap on the drum. If you have to drag an extra 50 feet of line off the drum to get to your full pull rating, you will limit your anchor points unless you are always having to reach anchor points in the next county. Most recoveries are within the first 50% of the line, which leaves you with a de-rated winch to start with. The 7/16ths line is probably overkill, but more and lighter strength synthetic is not necessarily the answer either. Rope also is susceptible to damage from sunlight and heat whereas steel line is not.

I consider synthetic line to be disposable, one-season equipment. After that it is suspect. It might be fine, or it might not. Keep in mind that the colorant used on rope is there for UV protection and lubrication. Once the color is gone, so is the protection, and there is no way to gauge the remaining strength in frayed or sun-damaged synthetic line. I would use synthetic rope of the same physical size as the wire rope it replaces, or one size larger (much of the synthetic rope is actually metric -- get the best you can afford but don't go down in size).

All that said, I would not worry about it. Use it safely, keep your fingers out of the fairlead, don't handle tensioned line even with gloves, always wear gloves even with synthetic line, don't take chances, and before you know it, you will understand your system very well. It is stronger than you might think.

[AndrewP]

Good post madizell.

In a former life while in college, I was a rigger on a crane in the summers. I have worked with and around wire rope, and respect it very much. I much prefer it to synthetic line. I know that is heresy here, but the steel stuff is tough, resilient, cheap and more than adequate for the job.

In 10 years of 4 wheeling and occasional winching, I have never seen wire rope fail. I know it can, but I've never seen it break. I have seen or been involved in dozens of winch operations/recoveries. We always take precautions with line weights and the like. The most important precaution is to be conservative about winch pulls, and to double line even in borderline situations.

Synthetics, on the other hand, I have seen fail several times often at low loads. An unseen knick in the line and it will fail right there with no warning. Fortunately, it doesn't store a whole lot of energy, or cause much damage (mostly because of it's light weight). I like the idea of one season disposable line, but that gets expensive pretty fast.

Anyway, the whole WLL thing is mostly irrelevant to off-road recovery. When is the last time you saw a shackle fail? The common 3/4 inch ones are only rated near 4 tons, yet no breakage even with the cheap chinese made ones. I did see a tow strap fail once and that was pretty cool and didn't do any damage.

[ntsqd]

FWIW the Sampson page does have an article on splicing the 12 strand synthetic ropes. It is geared towards making eyelets into the end(s) of the rope & requires a fid.

I spent a day with some 1/4" Amsteel looking into possible field repairs and testing them to failure. Short of the eyelet splice (& resulting shorter line length) there was only one join method that I discovered that would fail the line rather than the join. No known to me knot would fail the line. All failed in the knot. I used to rock climb, so knots are nothing new to me and I did research possible options in the couple of knot reference books that I own prior to the testing. Even the so-called "Grapevine" knot commonly used in rope slings on climbing anchors failed at the knot. Characteristically all of the knot failures looked like the line was overheated.

However, a simple 'S' weave, repeated at least 5 times, passing one end through the other line at 90* repeatedly failed the line on either side of the join. A tool like a dull pencil is required to carefully work the line's weave open enough to pass the end through. It is a viable field repair that I would trust for a "Getcha Back", but advise anyone considering it to test it on a sample of their own rope first. And, of course once back home that whole line is scrap.

Madizell's comment about retiring ropes reminds me of the rules for doing so in rock climbing. Those rules, adjusted to the different type of use, would be a good place to start formulating a set of rules for retiring synthetic winch ropes. Age is only one factor in determining when a rope should be retired.

[madizell]

The "S" weave is part of the process of splicing on eyes and hooks in synthetic rope, and is worth a try if a rope fails in the field and you have no spare or any other options readily at hand. Also part of that process is running a length of one rope down the center of the other like a Chinese finger cuff. A combination of burying a length of one line inside the other, and "S" tucks at both ends would likely join a winch line sufficiently to be used. It should be replaced after that as soon as possible, even if the splice works.

Splicing instructions are available from most if not all of the rope manufacturers and distributors (source, not retail) such as Puget Sound Wire & Rope, which company distributes so-called "plasma", the high modulus poly rope that I prefer. Splicing routines are the same with all 12-strand ropes because the method is specific to 12-strand construction, not to the material from which it is made.

Knot strength relative to line strength is one of those things that we probably learned as Boy Scouts, but have since forgotten. The attempts at knot repair I have seen were all in competition under duress, and ended up looking like multiple Granny's. They don't work as a rule. Any knot which allows the tensioned lines to enter the knot at an angle all create a stress point that causes synthetic line to fail at the stress point. Heat from choking the line could be a factor, but analysis of line failure is difficult without equipment.

It should suffice to say that, for our purposes, failure of a winch line in the field should not be thought of as a viable option or preferred result.

[MuddyMudskipper]

Nice posts Madizell!

[ntsqd]

The "Chinese Finger Trap" portion is part of the Sampson procedure as well. No surprise there. The problem with it, at least as far as the Sampson instructions go, is that it requires shortening 6 of the 12 strands to 1/2 of the total insertion length - which is a many multiples of the rope's diameter. I did not include doing that in my testing for this reason. My premise for the testing was a quick field repair, and earlier eyelet splicing showed the un-braiding and trimming to not always be very fast.

My theory of the knot failures is that the localized stress of the bend in the line turned the stress into heat. The parted ends looked just like I'd used a flame to separate them. What I failed to recall prior to the testing was that no known knot is stronger than the rope in which it is tied. I should have concentrated on splicing methods from the start.

In my testing of the 'S' weave I did not bury either end in the center of the other line. At 5+ passes it did not prove necessary to strength though if the repairer had the time it certainly would aid in going through the fairlead and in spooling onto the winch drum.

[madizell]

Cutting strands to differing lengths creates a taper which spreads stress. I find it tedious even to remember how to do it, and have to refer to written instructions every time, but it does work very well. The whole point of the splice process is to spread the stress of repair over a long length of rope. I don't know what the strength ratio is for such splicing, but it is close to the original strength of unspliced rope.

At one point I carried a splicing kit in the Jeep - fid*, electricians tape, instructions, light line for doing cross-stitching of the splice to anchor the joint, and so on. Now I just carry extra prepared ropes and do the splicing at home.

* A fid is a probe device used to aid in weaving splicing strands through the body of the line. I made mine from coat hangar. You can also use a pencil or pen, a screwdriver, or anything shaped similarly. It works something like a big needle.

[R_Lefebvre]

I have tweaked the frame on my CJ-7 with only an 8,000 pound winch by pulling more than I should, off angle (diagonal stress). Better not to use the full capacity of such a winch unless you are pulling on a 2-ton utility truck, which is to say you should not see the winch stall under normal self-recovery scenarios.


Hmmm... this concerns me.

Last week I used my new winch and bumper (ARB, and EP9) for the first time... you guessed it pulling stumps.

The first couple stumps weren't too big and had rotted for about 10 years so they were cake. Armed with a false sense of confidence, I tackled a large fresh stump. I cut all the roots I could, but guessed there was more going straight down. I was using my snatch block to double up the line, and hooked it back to my factory recovery point on the driver's side frame. I used a large shackle, I think 7/8", that was attached to the snatch block, and then I had my chain doubled up around the stump. I was trying to keep a mind on the force and doubling up everything since the line was doubled. I have 2 extra large shackles in my kit for this reason.

Well, now you know of course I just dragged my truck. I had the parking brake set and the trans in park. Not sure if this is the best way to go. I was a little worried about overstressing the parking pall? Oh, it was in low-range too, figured that would help. I noticed when the truck was dragging forward, one of the front tires was actually rolling, which I didn't understand. Then I realized the driveshaft was locked, but probably the other tire was rolling the opposite way because of the diff.

So it wasn't doing much to the stump, until eventually my front bumper started pushing on another large tree, resting against the passenger side front. I was being careful going slow, and then I saw my bumper start move a bit relative to the body, and I gave up. I was worried about "tweaking" my ARB. Soon as I saw it move, I stopped. I don't think tweaked it. It's still dead level. I notice the gap from the body on one side is slightly less than the other, but no angle. I think that was just the tollerance from when I installed it.

I realize now, it would have been better to attach the end of the winch cable to another tree. That way the truck would only have 9000lbs pull, and the tree would share the load. Obviously 18,000lbs was more than enough to pull the truck.

Anyway, now I wonder if I may have twisted the frame or anything? I haven't noticed anything odd at all, and never would have thought of it again if I hadn't ready that. I figure, if the ARB crush cans didn't collapse, there's no way I could have bent the frame?

Was any part of this rigging particularly dangerous? I was trying to double everything up, including the chain I wrapped around the stump.

[TJVach]

Anyway, now I wonder if I may have twisted the frame or anything? I haven't noticed anything odd at all, and never would have thought of it again if I hadn't ready that. I figure, if the ARB crush cans didn't collapse, there's no way I could have bent the frame?

Was any part of this rigging particularly dangerous? I was trying to double everything up, including the chain I wrapped around the stump.

"The mounting system is the single most important part of a bull bar design. ARB's mounting systems are specifically engineered for each vehicle, and are designed to spread impact and winching loads evenly over the vehicles chassis, ensuring the bull bar functions properly in extreme circumstances"

This is directly from the ARB USA website speaking about their winch bumpers. I'm not sure if this pertains to your situation, but I was always under the impression that that is what the ARB bumpers are designed to do.

I'm not going to say that your rigging was dangerous, because I am not even close to an expert at winching/setups. If it were me I might tie my truck off to another anchor point in the rear. I don't know if that is a good idea but I figured I'd throw it out there.

[michaelgroves]

Obviously the best scenario if the winch and rigging get overloaded is for the winch to simply stall. All the other components should ideally be strong and secure enough to not break up to and beyond the capacity of the winch itself. One good thing about a hydraulic winch is that the ultimate stall torque is very well regulated by the bypass valve on the pump. Electric winches produce undefined but potentially huge strains on the rigging at the instant of stall.

In any case, in practice, there are shock loads, invisible flaws in components, and some unknowable factors that mean that sometimes other parts of the rigging will fail. Being prepared for a breakage is a key part of winch safety. So even if you have a cable rated beyond the winch's capacity, you should treat it as if it might break.

For one thing, winches are not lifting devices, (hence the low safety margins on winching equipment between ultimate breaking strain and rated capacities). Any situation where the load can run away uncontrolled is "lifting", so if one's pulling up a gentle slope, there should be a driver in the winched vehicle to put the brake on. If it's too steep to hold with brakes, then a second rope should be tailed in while winching, anchored separately from the winch rope. I seldom see it done, but it's really not that difficult, and the alternative is risking your whole vehicle in the hopes that not a single one of perhaps a dozen different cheaply made, hard-used, seldom inspected, and poorly maintained rigging components will fail, despite having a low safety margin built in!

(Obviously, of course, most winch pulls are not done to move vehicles up or down gradients - by far the majority are extractions from mud holes, or out of ditches, or out of some awkward situation where the truck is grounded. In which case the secondary rigging is not necessary, as no significant falling is possible).

I personally favour good synthetic (HMWP) rope for winching. I certainly can't agree with the idea that they are only good for one season - I've used mine (moderately heavily, but carefully) for around six years now, and it's still up to the job. I don't trust it, of course, but then I don't trust any winch cable!

And this brings me to one of the biggest benefits of synthetic rope (and this goes to the OP's question): that if anything breaks, let it be the rope. If you've rigged to take care of the possibility of a runaway load, then it's almost unheard of for an HMWP winch rope to cause injury through breaking. The real danger is when, say, a shackle on the end of a snatchblock breaks. Then the whole snatchblock can come flying back at high speed. Same problem when any rigging hardware breaks (towing eyes, harnesses, tree-strops etc.). Unlike Andrew P, I have seen a couple of shackles and winch hooks break, and several steel winch cables, luckily all without injury. And don't let's get started on dangerous breakages when using kinetic ropes!

So for safely rigged winching, failure of (synthetic) winch line is about the safest breakage scenario there is. I will probably never retire my synthetic rope unless it's visibly damaged - but I do now carry a spare rope, new and complete, which will take me five minutes to install in the event that I break my first rope. (I could, of course, use this spare as my extension rope and as my tailing rope as well, but in my case, I've carried another rope for that purpose ever since my primary rope was new).

[jcbrandon]

Thanks to all for your advice and perspectives. I think I'm starting to get a handle on all of this.

As an aside, in my professional life I get to work with some pretty interesting materials (carbon and aramid fibers, thermoplastic adhesives, all kinds of cool stuff). I have a meeting this morning with two gentlemen from DSM Dyneema in the Netherlands. These are the folks who make Dyneema, "the world's strongest fiber". That's what Amsteel Blue and other high-performance winch lines are made out of. Not sure if I can work off-road recovery into the conversation, but it should be interesting nonetheless.

[michaelgroves]

I don't think anyone mentioned it explicitly, but of course it should always be remembered that all the loads on the "far" side (the side with the shackle) of a snatchblock (including the load on the snatchblock itself) are higher than the loads on the "near" side (the side the winch rope enters and exits). Anything up to double the load. So whatever you anchor a snatchblock to, needs to be strong enough to take twice the winch's pull.

If you use two or more snatchblocks on the same winch line, each of them will generate double loads on whatever they are anchored to, so try not to ever have two snatchblocks attached to the same anchor, unless it is suitable for four times the winch pull.

Your winch cable, of course, doesn't come under additional strain, and nor does its anchor point.

(Each snatch block you run the winchline through can effectively add "x" amount of total pulling force, where x is the rating of your winch, less some percentage loss for friction - usually estimated at around 15-25%. So one snatchblock can give you (nominally) twice the total pull, two snatchblocks, three times the pull, three snatchblocks, four times the pull etc. But as I said above, each snatchblock and its anchor comes under double the strain of the winchline itself, which is easy to remember.)

[Antichrist]

Reading through this I saw a couple of statements that x diameter cable has a breaking strength of....
Wire rope comes in many different ratings. For instance, 7/16 19x7 IWRC Rotation Resistant at 16,600lbs to 6x19 Class IWRC Long-Wear at 23,800.

Personally I prefer wire rope for the type of work I put it to. But I've worked both as a rigger for heavy construction, with a lot of overhead lifting and as a skidder operator with a lot of winching in the woods in rough terrain. I've also been working with vehicular winches for going on 35 years. Unfortunately a lot comes with experience, which can be rough for the inexperienced.

Awareness of your equipment is the key. Don't worry about "fuses", though the shear pin on my deuce and half PTO winch came in handy a couple of times.
Make sure your equipment is in good nic and properly sized (absolutely key) and an electric winch will likely stall before anything breaks.

[madizell]

No doubt you are right about different classes of wire rope, and certainly it is good information to have. Most of us who use wire rope on a winch, however, use the rope provided by the manufacturer, or a replacement unit from standard suppliers. My guess is that the winch suppliers are using wire rope nominally suited for the job, not the very best that could be used, which would be why the rating quoted for a size rope were mentioned.

Making the change to high grade wire more difficult, it takes specialty equipment to properly connect eye ends to wire rope to be used in high tension situations. I don't know anyone who has this equipment. Do the suppliers of high grade wire also make the appropriate eye ends on request? Does the high grade wire have handling restrictions or flexure limitations that would make it unsuitable for use on a recovery winch? Can it be used, for example, on a 3 1/2 inch drum and can it run through a hawse or roller fairlead with the minimal angular dimensions found on off road vehicles?

[Antichrist]

No doubt you are right about different classes of wire rope, and certainly it is good information to have. Most of us who use wire rope on a winch, however, use the rope provided by the manufacturer, or a replacement unit from standard suppliers. My guess is that the winch suppliers are using wire rope nominally suited for the job, not the very best that could be used, which would be why the rating quoted for a size rope were mentioned.True, as I recall when I contacted Ramsey, their supplied 3/8" wire rope was rated at about 16,000lb.


Making the change to high grade wire more difficult, it takes specialty equipment to properly connect eye ends to wire rope to be used in high tension situations. I don't know anyone who has this equipment.Most any rigging company has the equipement on hand. Phone book under Rigging or Crane Rental.

Do the suppliers of high grade wire also make the appropriate eye ends on request?Some yes, some no.

Does the high grade wire have handling restrictions or flexure limitations that would make it unsuitable for use on a recovery winch? Can it be used, for example, on a 3 1/3 inch drum and can it run through a hawse or roller fairlead with the minimal angular dimensions found on off road vehicles?Actually the higher rated rope I quoted is more flexible than your standard OEM wire rope. Also you can get a field replaceable end for it that is rated to match the rope.

[NothingClever]

Great post. Thanks to all for rendering their wisdom, observations and experience.

I have a coupla questions (somewhat ancillary) related to the OP.

I like the idea of ARB's crush cans in their bumpers to make the bumper compatible with air bag sensors to prevent premature deployment.

Q1: Is this a proven feature or is this merely marketing?

The reason I ask is because I am going to purchase a front bumper soon and I want it set up for a 2" receiver (winch on a winch cradle for front or rear anchoring).

Amongst the options are, of course, a custom bumper from Armorology, RockWare, Irbis, etc, etc. My issue is I don't have the time to drop off the truck for a few days at one of those locations.

Another option would be to pick up an economical ARB and have a knowledgable welder weld the receiver to the ARB. I think even after the welding, I could save around $300 which, to me, is enough fuel to get me to somewhere around Merida, Yucatan (the long way).

Q2: Anybody have any thoughts on welding an ARB?

Thanks in advance.

[rambrush]

Yes the ARB does have the crush zones. Yes ARB states in the paperwork any and all warranties are void if the bumper is modified.
Thus there has been a mod that you actually connect he receiver to the front frame horns. I don't have the time currently but if you search around a bit you should be able to locate it. It might even have been over on the TTORA website forum

[NothingClever]

Yes the ARB does have the crush zones.

So, are they truly functional or simply marketing?


Thus there has been a mod that you actually connect he receiver to the front frame horns. I don't have the time currently but if you search around a bit you should be able to locate it. It might even have been over on the TTORA website forum

Thanks....I'll check it out.

[cruiseroutfit]

So, are they truly functional or simply marketing?...

I doubt anyone with a stitch of ethics or a sense for liabity would market a bumper as 'airbag approved' with crush cans if it were not the case. I'm thankful the market hasn't eroded to such tactics.

Yes they work and even more so they are tested to be compliant and crush and decelerate per specifications. They are a really neat design that allows crush, yet also allows winching loads through the use of "shear tabs" that break or bend in even of an accident. Furthermore for minor accident where the bumper is not compromised but the crush sections are, these parts are sold individually from ARB.

There are pictures of the ARB crush cans here:
http://expeditionportal.com/forum/showthread.php?t=5371&highlight=crush

There were some detailed pics of the units themselves here but it looks like they were lost with the database issues, none the less there are some details here:
http://expeditionportal.com/forum/showthread.php?p=169775&highlight=crush#post169775

ExPo member Nic (Willman) built a neat bolt in 2" receiver for his ARB bumper, something similar could likely be done for most models.

[Willman]

ExPo member Nic (Willman) built a neat bolt in 2" receiver for his ARB bumper, something similar could likely be done for most models.

Here is what i did....from my build thread..



http://i51.photobucket.com/albums/f374/nicwillman/ARB%20Bumper/DSC01481.jpg

I love my portable Warn winch system that i have on my rig. I need to fab up a front reciever hitch for my winch setup. so...I got out the metal and went to work.

I used 1/4" material since the ARB is only 1/8". I made a plate that goes over the opening for the winch and simply just put a reciever there. I wanted something that looked shape and could be removed in the future.
Here I go!

http://i51.photobucket.com/albums/f374/nicwillman/ARB%20Bumper/DSC01577.jpg

The ARB needed to moded alittle to fit the new reciever.

http://i51.photobucket.com/albums/f374/nicwillman/ARB%20Bumper/DSC01579.jpg
http://i51.photobucket.com/albums/f374/nicwillman/ARB%20Bumper/DSC01583.jpg

Drill the holes and placed the place for fitment. Then i finished welding it all up.

http://i51.photobucket.com/albums/f374/nicwillman/ARB%20Bumper/DSC01588.jpg
http://i51.photobucket.com/albums/f374/nicwillman/ARB%20Bumper/DSC01589.jpg

All ready for some paint. The pin fits nice and so does the winch.

http://i51.photobucket.com/albums/f374/nicwillman/ARB%20Bumper/DSC01592.jpg

Hope this helps

Front/rear mounted winch are a sure great!

I have since sold the winch and the reciever due to buying a trailer....

:)

[Bongo Boy]

Most extraction pulls offroad are in the 3000-4000 pound range, unless pulling a huge truck out of deep mud, or a completely dead tuck up a difficult spot.What's the basis for that statistical citing?

[Bongo Boy]

WLL ratings are for overhead lifts, and typically 4X breaking strength.You're saying that the only working load limit ratings that exist are for overhead lifts?

[ntsqd]

WLL's are based on the expectation that the load will be overhead since lifting things is what most rigging is used for. The appropriate Factors of Safety are built into the WLL's.

[AndrewP]

What's the basis for that statistical citing?


There was an article several years ago in a Jeep mag, and they had a tensionometer and did a bunch of scenerio type pulls. They were not as high as you might think. Pulling out of a mud bog I think was the highest and near the winch capacity. Obviously a mired Unimog will take more of a pull to free than a mired TJ, but for most 4000-5000 pound trucks, the quoted figures are what I remember. It goes along with my seat of the pants gestalt too, but I don't live or wheel in a muddy environment.

The WLL are for overhead lifts, yes. Breaking strength is MUCH higher. I always have figured that a rated hook or shackle will not break in a recovery type situation. The winch line is virtually always the weak point since it isn't typically rated, and if it were, the rating on 5/16 cable (the most common size) would be in the 2500 pound range!

[Antichrist]

I like the idea of ARB's crush cans in their bumpers to make the bumper compatible with air bag sensors to prevent premature deployment.

Q1: Is this a proven feature or is this merely marketing?Yes, proven to do what they claim. That said, there are some good technical articles available that go very deeply in to the physics of crashes, deceleration, inertia and other factors in how they relate to trauma on the human body. The upshot is that there is negligible difference, in a crash and resulting injury or lack thereof, between an airbag compliant bumper and one that isn't.

Another important factor to consider is the law in your country. In Australia for example, where the ARB is made, my understanding is that it's against the law to replace the bumper on a vehicle that had an OEM airbag bumper, with one that is non-airbag compatible. Contrast that with the US where there are no laws regarding bumpers as they relate to personal injury. The laws in the US only govern the area of car makers and limiting the $$ value of vehicle damage in an accident. The laws in the US were passed as a result of too much body damage during low speed impacts.

[madizell]

Yes, proven to do what they claim. That said, there are some good technical articles available that go very deeply in to the physics of crashes, deceleration, inertia and other factors in how they relate to trauma on the human body. The upshot is that there is negligible difference, in a crash and resulting injury or lack thereof, between an airbag compliant bumper and one that isn't.

Another important factor to consider is the law in your country. In Australia for example, where the ARB is made, my understanding is that it's against the law to replace the bumper on a vehicle that had an OEM airbag bumper, with one that is non-airbag compatible. Contrast that with the US where there are no laws regarding bumpers as they relate to personal injury. The laws in the US only govern the area of car makers and limiting the $$ value of vehicle damage in an accident. The laws in the US were passed as a result of too much body damage during low speed impacts.

It is, as you say, mostly a matter of politics, not a matter of science.

[madizell]

The WLL are for overhead lifts, yes. Breaking strength is MUCH higher. I always have figured that a rated hook or shackle will not break in a recovery type situation.

True as far as you go. However, overhead lifting generally produces static loads, so that having an industry normal 4X break rating constitutes an adequate safety margin only in a static lift.

But when a static load rated device is used in a dynamic situation, all bets are off. First, it is not that difficult to produce 20,000 pounds of energy with a 5,000 pound vehicle using nothing more than a snatch strap. Typical shackles are rated at 3.5T, and some at 4.5T unless you use the military monster shackles intended for recovering 6x6 trucks. Our typical shackles are rated for 7,000 to 9,500 pounds of static load, without regard to assumptions about safety margins. Obviously it is not impossible to place that much load on the shackle with an ordinary winch of the 8,000 to 9,500 pound rating, even if the load is basically static. If we were working with a lifted load, we would not routinely exceed the working limit of the equipment. Why is it okay to do so with a dynamic load?

Now use the same shackle to capture a sheave in a double line pull. Although the winch cable itself may be under no more strain than the rated pull of the winch (say 8,000 per line), the shackle and whatever you use to attach down line from the pulley is going to have twice the stress. Now you are looking at potentially 16,000 to 19,000 pounds of stress, even if we assume the load to be static. This places the strain on the shackle somewhere well into the safety margin of a 3.5T shackle.

However, vehicle recoveries are never static unless everyone has walked away from the job. Mass in motion causes accelerated strain on the system, and does so in ways that, without measuring equipment, we can not really determine or predict. I would expect that dynamic stress added to a recovery situation is never more with a double line pull than it would be with a single line pull, but even so, if you add 10,000 pounds of momentary strain to an already fully loaded double line recovery, you are very closely approaching the ultimate failure point of a 3.5T rated shackle, even though the winch cable is still within its rated capacity.

It is not always the winch line that fails first, and it is never safe to make assumptions about safety margins. In vehicle recovery we are always using dynamically equipment that is rated statically, and we can not control the variables. Whether the breaking point of a device is or is not MUCH higher than the WLL rating is, in my opinion, not relevant. It is not safe to work above the rating of your equipment.

[AndrewP]

It is not safe to work above the rating of your equipment.


So what are you saying? Stay within the WLL of your shackles? That's 4 3/4 ton and so more than enough for most recoveries. For the rare times it isn't less than 4 3/4 tons, the breaking strength is above 4 x 4 3/4 which is about 19 tons which is 38,000 pounds. I would worry far more about the part of the truck the shackle was attached to, rather than the shackle itself. I don't think there is any practical recovery point on a jeep that would even approach this kind of strength..ie the vehicle would break before the shackle.

Having recovered numerous vehicles and seen countless more recovered by others, The common 3/4 shackles we all use have never been an issue. Winch lines, yes, pull straps, yes, but never shackles. I doubt it would even be possible to generate the type of force that could threaten the breaking strength of a 3/4 shackle in the usual offroading environment. There is always something else in the system that would fail first.

And an update__I just went out to the garage and checked the 3/4 inch shackles on the rear bumper of my FJ40. The right shackle is rated at 6.5 tons (Made in USA Breaking strength above 52,000 pounds). The left side is a made in China shackle and rated at 4 3/4 tons. Being practical about this, neither of these is likely to ever fail in use, but interesting there is that big a difference in the ratings.

With all of that said, there are non-rated shackles sold and in use. I've seen them at Tractor Supply. I would avoid those entirely.

[madizell]

The different rating is attributable to the quality of the metal.

Not saying you should not ever work above the WLL. What I am saying is that because we can't control the variables in a dynamic recovery, it is presumptively not safe to work above the rated limits of the equipment, and in particular, it is not safe to make blanket assumptions based on manufacturer's built-in margins for failure. The margin for safety is only that when the equipment is used as intended. In a static lift, a 4X safety margin accounts for minor shock loading associated with a gradual lift, traverse, and lowering of a load, and also accounts for wear and tear, metal fatigue, and whatever else might arise in use when lifting heavy loads. Still, I don't believe anyone would argue that it is appropriate or safe to lift loads in excess of the WLL of the weakest component when making overhead lifts.

If it isn't safe to do so in an essentially static vertical load, how can it be safe in an uncontrolled dynamic recovery?

So, I am not saying you can't recover a load heavier than the WLL, and I used shackles as an example only because we all use them and they all have a rating stamped on them that is easy to find. All I am saying is that ignoring the possibility of breakage, or assuming that if anything breaks it will be the rope or cable, is not safe practice and may not always bear out. Just something to consider rather than presume our personal safety. False assumptions about safety margins might some day lead to carelessness. I exceed the safe limits of my recovery equipment quite often, but not without thinking about it, and I guarantee I get way out of the way when I know I am pushing the envelop.

I also disagree that you can't find a spot on a vehicle which will sustain loads in the 30,000 plus range, as long as you are willing to consider dedicated off road toys, and not just OEM bumpers. Or if that seems too extreme, loads in the range of 20,000 pounds are not hard to carry with properly constructed and placed recovery points, even on overland vehicles. Perhaps one of the engineering or mathematically privileged in the crowd can provide either the formula or the answer to the question of how much load/force/strain is created by a 5,000 pound vehicle going 5 miles an hour when it hits the end of a non-dynamic restraint. I suggest a non-kinetic strap or chain example only because it eliminates from consideration the force-over-time component of an otherwise kinetic situation, but I don't think it significantly changes the answer either way.

Having snatched any number of vehicles weighing equal to or more than my 5,300 pound trail weight, and knowing the verve with which these heavy vehicles have become unstuck (bordering on airborne), I assume the apparent force at the end of the strap is significant, and since we all seem inclined to occasionally connect such straps to ours and others' vehicles using the odd steel shackle (we shouldn't but we do), it might be interesting to know just how much force we generate under the circumstances.

[Crookthumb]

Here is a video of a recovery when the frame was the weakest link. Right around the 7:50 minute mark is when it goes bad. Sure glad that wasn't me.

http://www.youtube.com/watch?v=BEWHqIOGsVo

Now if he was going to daisy chain it like that he should have hooked up to a rear reciever. This way the angles would have been in line with each other rather than using the boom or whatever the triangulated thing is called.

[kerry]

Here's the short version of that two truck driver's bad day:

http://www.youtube.com/watch?v=gqCy7ZxVdgI&feature=related

[kerry]

I don't think that truck would have broken had the truck in front not been stopping the front of the tow truck from going up in the air.

[Crookthumb]

I don't think that truck would have broken had the truck in front not been stopping the front of the tow truck from going up in the air.

I agree. The tow truck driver operator seemed pretty clueless.

[Redline]

But it sure shows the force involved when vehicles are stuck in mud/slush etc. Getting some speed up and yanking on a strap puts the strength of rigging in question, as Madizell points out.

I know I have been lucky in the past when momentum seems to work when nothing else will.

[madizell]

Seems like some folks will go to any lengths to get on TV. Did anyone see any of these guys do anything right?

The tow truck driver looped steel chain around the ball hitch of the pick-up in front.

Failing to pull a mere Disco out of the mud from the front, would it not have been prudent to do it from the back, the direction in which the vehicle entered the obstacle, and the direction in which resistance to recover would be least? The guy drove out eventually by passing just behind the Disco so obviously he could have accessed the Disco from the rear.

Eventually two vehicles were recovered, but each was pulled out with (what appeared to be) chain attached to a tow hitch on the tow vehicle. One was seriously snatched. This can only lead to damage to either or both vehicles.

The guy driving the chipper truck never got out to verify how his tow rig was attached, and the kid fiddling with the tow chain did so repeatedly while the chipper truck was in motion. Who needs fingers?

The daisy chain idea was to anchor the tow truck because it was sliding. The anchoring vehicle in such a situation should never attempt to move while under tension, much less drive, much less hit the end of a chain while in motion, and the guy in the tow truck should not have allowed such shenanigans. And I would agree that because the towing vehicle was a tow truck with a boom, it should not have been anchored because of the angular stress. It was also more likely that it was the truck bed that failed, not the frame, but it could be both.

Neither of the stuck vehicles was deeply stuck. The difficulty shown in the recovery of each was due more to the inexperience of the guys involved and the inadequacy of their equipment than in the condition of the stuck vehicle.

This is like some kind of Jeff Foxworthy skit. If you think these guys have it together, you could be a redneck.

[kerry]

It was also more likely that it was the truck bed that failed, not the frame, but it could be both.

If you slow down the video, you can see the frame cracked in two, just behind the cab.

[xcmountain80]

Can I point out this is not a REAL tow truck, just because it has the rigging that billy bod ordered from the local auto parts store doesn't make it a tow truck. I have liked to have seen an actual tow truck pull him out. That rig was designed for pulling cars from accident scenes or disabled vehicles. This was clearly a stuck and disabled vehicle, I wonder if the tow guy was like well you owe me a new truck?


Aaron

[Redline]

Yep, a single-rear-wheel, single boom truck, maybe intended for Repos or (easy) off-highway recoveries. But I agree that the real problem was the loose-nut-behind-the-wheel.

I know little about recovery but certainly a bit more than that bozo.


Can I point out this is not a REAL tow truck, just because it has the rigging that billy bod ordered from the local auto parts store doesn't make it a tow truck. I have liked to have seen an actual tow truck pull him out. That rig was designed for pulling cars from accident scenes or disabled vehicles. This was clearly a stuck and disabled vehicle, I wonder if the tow guy was like well you owe me a new truck?


Aaron

[xcmountain80]

Why is it that jobs requiring some skill always attract the not so skilled?


Aaron

[madizell]

Why is it that jobs requiring some skill always attract the not so skilled?


Aaron

Usually because they don't regularly pay very much.

[madizell]

If you slow down the video, you can see the frame cracked in two, just behind the cab.
All I can see is a gap between the cab and bed. Even stopped, I can't see the frame at all. I suppose it could be cracked, but since the frame channel on the Ford is a C-channel, not boxed tube, I would expect that it simply collapsed without breaking. They are not that hard to bend. I wonder if any of the folks in the video actually owned any of the vehicles they were driving, with the possible exception of the old Toy pickup. These looked like kids driving Mom and Dad's vehicles, and the tow truck guy is anyone's guess.

[Crookthumb]

Failing to pull a mere Disco out of the mud from the front, would it not have been prudent to do it from the back, the direction in which the vehicle entered the obstacle, and the direction in which resistance to recover would be least? The guy drove out eventually by passing just behind the Disco so obviously he could have accessed the Disco from the rear.

He did try to pull from the rear. I originally saw the clip on Facebook. I didn't know if it would post here or not. If so it is a little clearer.

http://www.facebook.com/home.php#/video/video.php?v=86450905441&oid=2204603930

[Crookthumb]

I agree that there were so many things that should not have been attempted. Unfortunately many don't think about would could happen if something were to go wrong. Look at all the crap flopping around in the bed of the Toy. Get rid of it or secure it. Simple little things can have a big effect.

[toledotimber]

I know it's a bit late, but I figure since most of the posts were pretty off topic, no one will care. The weakest point in any winch rigging setup (so long as we're assuming that decent mounting points have been used and that no original parts have been replaced with non-original ones on the winch) is the pin that holds the winch hook to the cable, possibly in a tie with the mechanical crimp that forms the loop in the cable. The answers about the winch operator being the weakest link are cute, and often all too true, but I doubt what the O.P. had in mind.

[michaelgroves]

The weakest point in any winch rigging setup (so long as we're assuming that decent mounting points have been used and that no original parts have been replaced with non-original ones on the winch) is the pin that holds the winch hook to the cable, possibly in a tie with the mechanical crimp that forms the loop in the cable.

I'd agree those are possible points of failure, but not ones that strike me as the most common ones! Are you suggesting they are designed to be the weakest link? Or that it just turns out that way?

[AndrewP]

I think the pin idea is probably true, and in fact is why I upgraded from the 3/8 hook that the winch came with to a larger forged hook with a 1/2 pin. That way I know the hook is much stronger than the cable, and as an added bonus, is easier to get two tow strap eyes on when doubling up for a pull.

[ntsqd]

The pin and the area of the hook adjacent to it's hole do need serious attention during the design phase. The pin is loaded in double shear and it's calc's are fairly straight forward once the WLL and minimum Factor of Safety are set. The area around the pin's holes are similarly straight forward calcs though there are more of them. Where this whole aspect of the system will fail is substitution of inferior materials and seemingly small variances in final forged dimensions or in the location of the pin hole. In the region around the holes a small loss in cross section can have large effects. The bend in the hook is no small design challenge itself.
Given that those making hooks of quality have BT, DT I will trust that they have worked out a shape that takes all of this into account.

Personally, I'd rather set up for a shackle of a size appropriate to the winch than use a hook at all.

I would be more concerned with a non-thimbled rope causing too small of a bend radius around the pin. Such is exactly the same problem as a kink in a wire rope. I would venture that the synthetics are more forgiving of this, but I've no info on that.

[soenke]

......And this brings me to one of the biggest benefits of synthetic rope (and this goes to the OP's question): that if anything breaks, let it be the rope. If you've rigged to take care of the possibility of a runaway load, then it's almost unheard of for an HMWP winch rope to cause injury through breaking. The real danger is when, say, a shackle on the end of a snatchblock breaks. Then the whole snatchblock can come flying back at high speed. Same problem when any rigging hardware breaks (towing eyes, harnesses, tree-strops etc.). Unlike Andrew P, I have seen a couple of shackles and winch hooks break, and several steel winch cables, luckily all without injury. And don't let's get started on dangerous breakages when using kinetic ropes!

So for safely rigged winching, failure of (synthetic) winch line is about the safest breakage scenario there is. I will probably never retire my synthetic rope unless it's visibly damaged - but I do now carry a spare rope, new and complete, which will take me five minutes to install in the event that I break my first rope. (I could, of course, use this spare as my extension rope and as my tailing rope as well, but in my case, I've carried another rope for that purpose ever since my primary rope was new).


We use Dyneema rope as well on our MM for self recovery.
A spare rope ist perfekt but breakages can even be spliced or just knotted.
The main advantage is safty and weight!

We use Dyneema rope for that reason for the shackles too, I haven´t seen them mentioned so far. (and they are easy to store, no rattling when driving pists)

http://up.picr.de/1659609.jpg

http://www.svb.de/index.php?sid=2517f453041f559905bdcd64b264e010&cl=details&anid=116261&tpl=&pgNr=1&lang=1&listtype=search


(very expensiv) blocks are available with aproved operating loads up to 5000kg, though breaking load would be much higher

http://up.picr.de/1659566.jpg

http://www.kohlhoff-online.de/documents/Loop%20Products%20UVP.pdf

Sönke

[michaelgroves]

Some pretty nifty "shackles" and "blocks"! I like the idea of a lightweight, harmless shackle.

But I imagine that in practice, you'd have to go for a much heftier guage of rope shackle to match the strength of the winch-line. Synthetics don't like compressive forces, which is why they snap much more easily if they are knotted or belayed around something with a small diamete (hence the use of steel thimbles to make a hard eye at the end of the winch-line).

Rgds,

Michael...

[soenke]

our shackles are aproved for an operating load 10.000kg, never had a problem ...even using kinetik ropes. Befor I had smaller ones with 5.000kg, I just used two...

[ntsqd]

In looking at the linked page I see that the 10.000kg rope shackle is labeled as being "16mm". I would assume that most folks use 5/16"<->8mm rope on their winches (or maybe 3/8" - 10mm on the bigger winches), so the 16mm shackle would probably be enough larger as to avoid the tight radius bend within the shackle itself that kills this type of rope. Then so long as the the winch rope is properly eyeleted there should not be any problem.

I very much like the idea of these shackles, but I'm going to have to make some mental adjustments if I ever use any.

[Capt Eddie]

I have found the weakest link. The 3/8 inch clevis pin the is used to attach the hook to the cable. 3/8 x 1/2 inch piece of metal stands betwwen success and failure. We use four 1/2 inch bolts minimun to hold the bumper to the truck. Four 5/16 bolts hold the winch to the bumper. Our snatch block has 1 inch bolt thru the sheave. It all comes down to one little 3/8 clevis pin. But I have never seen or heard of the pin breaking. Why is this??

[ntsqd]

Because it is loaded purely in double shear and was sized for the job.

The bolts have to deal with complex combination's of tensile, single shear, and bending loadings; and have a lot tougher job to do.

[Bongo Boy]

There was an article several years ago in a Jeep mag, and they had a tensionometer and did a bunch of scenerio type pulls. They were not as high as you might think.Thanks--having at least some anecdotal data is very nice, even if there's a large range. Yes, I'm a little surprised by the numbers--I simply had no idea what they might be.

It's a great idea to have some idea of the weakest point in a complete recovery situation, not just in the frame-to-hook components on the recovery vehicle. I imagine a fine setup can be beside-the-point in cases where a bad hookup is made when recovering, either through carelessness or simply not knowing how the target vehicle is assembled.

[johnnyrover]

Weakest link = operator!

In my experience, rope is safer but subject to more environmental damage (including sand and ice); cable is more durable but dangerous when it lets go.

Failure points seem to be outside the winch/cable/block and more with the connection points (weak bumper, poor selection of recovery point, etc)

I have had both rope and cable fail, and finally settled on a hybrid solution.

We used a shorter cable on the winch with a rope extension (kept in the truck). This kept the rope away from the environment (sand, ice, sun) and reduced our exposure to cable under load.