wire rope damage

[peteinjp]

I've had my PTO on the truck for about 6 months now and I've used it a few times. Only once was I really stuck. After I used it that time I just loosely wound it on the drum figuring I'd get it nice and tight again in the following week.

My landlord came running over the next day- his farm truck (very light weight 660cc truck) was unable to get out of the rice field. It was a very light pull and if I had a tow rope with me that would have been the way to go but I didn't. When pulling him out I could feel the rope slip in between the loose cable on the spool. It got 2 good kinks in it one of which resulted in a strand slipping slightly below the other 6 strands.

Though in this case they are the result of poor practice it seems that kinks are kind of unavoidable in of road usage where angled pulls are often encountered.


Are you guys able to keep wire rope damage/kink free during pulls??

If not then how do you decide how much damage is too much?

Typically how much use do you get out or a rope before you typically replace it?


Pete

 

[Pin_Head]

Are you guys able to keep wire rope damage/kink free during pulls??

If not then how do you decide how much damage is too much?

Typically how much use do you get out or a rope before you typically replace it?


Pete

No. It unavoidable and it is going to get bent and kinked in a real world application.

If you have more than 2 strands broken in 30 cm of cable, you might want to start thinking of replacing it.

If it parts during a pull, you definitely need to replace it.

 

[Gottagetone]

Go synthetic!

 

[peteinjp]

Pin Head- what do you mean by "parts?"

No strands are broken yet. Just one is crushed into the core a bit. I think it was loose underneath a section of rope that had tension on it and that is how it got kinked.

P

 

[Pin_Head]

When a cable parts, it separates into two pieces.

 

[roalco]

If it's kinked, or crushed, replace it. Wire rope is cheap (synthetic line too) compared to what a winch line can do to you when it fails under load!

 

[peteinjp]

Parts as in comes flying at ya- gotcha.

I hear ya on replacement. But if it's going to get kinked it doesn't make sense to replace it after every 10 pulls. What I'm getting at is what is a practical way to decide how much damage warrants replacement. Somewhere between Pin Heads "parting" method and Roalco's replace it every time there is any damage.

Synthetic..... Hmmm I'm thinking I'll get a synthetic line to carry for extension and to have on hand in the even that the wire rope gets trashed in the middle of a trip.

Pete

 

[Wile E Coyote]

Pete, Pinhead gave you very specific parameters for when to replace wire rope (more than 2 strands broken in 30cm of length). Another way to say 'parts' would be fraying, unwinding, etc. and not necessarily totally failing into pieces.
Damage to a rope requiring replacement is inevitable, but it isn't normal to have to do so after every 10 pulls. You already noted one common reason for failure (improperly spooled onto drum). Also, watch the fairlead for pinch-points and try to avoid pulling at extreme angles, asking the wire rope to make very tight bends under load will shorten it's life considerably.
As far as synthetic, know that a good way to damage it is from fairlead rollers that are chewed up (burred) from wire rope...so immediately replacing wire rope for synthetic without proper prep, like while on the trail, wouldn't be ideal. Sure would stink to trash a brand new synthetic line.

 

[george_tlc]

Wire rope is well proven over many years of history, but it is a pain to use and requires tensioning after every use if you want to prevent 'mashing' damage as you pull your vehicle from chassis deep mud and the highly tensioned cable squishes the living life out of the lower wraps that are all loose.

That's one reason folk try to unspool as much wire as possible to a winching anchor point (the other is obviously the mechanical advantage of less wraps on the drum).

I switched to synthetic 9+ years ago and have never looked back. The synthetic has it's own issues in terms of abrasion etc, but the ease of handling (just acts like wet noodles when unwound), nice to handle when cold, no need to spool/tension it perfectly, reasonably safe to handle without gloves, lighter on the front end, etc etc, makes choosing it a no brainer in my experience.

I have a ton of wire extensions etc made from 'good' sections of otherwise damaged/kinked wire that it became obvious that wire rope is just a pain to use on day to day vehicle winch use where the wire will generally not be fed on perfectly since every winch extraction is happening in less than ideal conditions.

Synthetic may cost more initially, but I've found it to be a lot more durable and forgiving when used in the field.

Winching a mate stuck in mud to the chassis. Synthetic line from my 8274 winch. I'd already winch my other mate that was also stuck (the other tracks):

cheers,
george.

 

[peteinjp]

Thanks Guys- and in fairness Pin Head did give useful specifics. So is it fair enough to say that a broken strand on a 7x19 rope reduces the capacity of the rope by at least a 1/7th. Until now I never even considered using a rope with a broken strand. The current rope is not broken anywhere it just has one strand crushed into the core a bit. Needless to say I'll keep a very good eye on the condition and I'll think twice before do a hard pull with it.

Pete

 

[roalco]

Just don't forget that all the riggers calculations for acceptability of damaged wire rope (number of adjacent broken wires/given distance etc) are based upon the rope bring used in with a standard 5:1 safety factor (regular dynamic applications). That puts the max pull on a 3/8" 6x19 grade 110/120 IP with a wire core ( that would be a good winch line, domestic made from a recognized manufacturer) of 1.2 tons, or 2400 lbs. This means a new, undamaged, uncorroded, clean, properly lubricated wire rope of that size will fail (break or "part") right around 12,000 lbs straight static pull. 5/16" of the same spec has a rating of .88 tons and fails at around 8,800b. Now figure out what size you have on your winch, what your winch can pull, what quality of wire rope you have ( did you get it from a rigging company or was it made offshore and sold for farm use ????) and what condition it is in ( externally and internally).
Basically, most vehicle winches are running their lines right up to the breaking point from new, you have no safety factor .... So be careful!

 

[Pin_Head]

The standards I have seen for wire rope wear and damage are for its use in over head lifting, like in cranes. You need a much larger safety factor in this application than in what winches typicaly get used for. If you do any angle pulls, the cable will get spooled up on one side of the drum and will not lay flat as a tightly wound layer. Because of this, it will tend to slip between wraps and get kinked in normal use. If you had to replace a kinked winch cable, you would need to replace it every time you do an angle pull. Use common sense. When a lot of strands are broken and crushed, it is time to get a new cable.