Curosity question really - but - how are winches rated?

The rule of thumb appears to be to use a winch with a load rating of, at a minimum, 1.5 times the gross vehicle weight - so for a 3,800lb truck, you would want a minimum of 5,700lb, so that would translate to an 8,000lb, 8,500lb or 9,000 lb winch, and you'd couple this up with a shackle rated for perhaps 3.25 tons or 7,150 lbs.

Now that shackle rating is safe working load - you can safely use that shackle to LIFT 7,000 lbs - the proof load on that shackle would be roughly double the working load, and the breaking load as much as FIVE times the SWL.

So - how are winches rated - can a winch with an 8,000 lb rating actually lift 8,000 lb?

For example - bolt the winch to the side of a barn, run the line completely off of the drum save for 3~4 turns, over a snatch block and then to a sling attached to the four wheels of the vehicle (as would be used to lift it off of a ship) - and power the winch from a large bank of batteries (to ensure unlimited amperage) - can an 8,000 lb winch lift an 8,000 load?

Let's assume my 3,800 truck is at the bottom of a 1:2 gravel slope, no mud or sand, the problem is a lack of traction, the vehicle is not bogged, and there is none of that "suction" that occurs with a bogged vehicle - can I expect that 8,000 lb winch to pull the truck up that slope?

Last question - are all winches rated the same way?

I've come across a couple of brand new series 70 Toyota Land Crusier troop carriers, 3300kg GVW, and these were equipped with a 2000kg winch - factory fitted - and I have seen them pull seriously bogged vehicles, well over the 2000kg rating, out of the mud, when a section of the road washed away.

Great queations Fordum, I wish I had something to input. I too would like to know more about this. I've wondered if I could use my winch, with a snatch block ( shackle ) slung over a large tree branch to actually lift my Tracker front end off the ground.

An 8000lb winch should be able to pull with 8000 pounds of force.  So it would be able to pulling a 8000lb vehicle on flat ground with no resistance, or dead lift 8000lb worth of weight.

Note that most winches list the rating for the pull with only a single wind of cable.  For most winches you will be pulling with 4 levels of wrap, dropping the winch rating down.

For example the default Harbor Freight/Chicago Electric 8000lb winch:

1 wrap - 8000lb
2 wrap - 6900lb
3 wrap - 5600lb
4 wrap - 5100lb

Compared to a Warn 9000i

1 wrap - 9000lb
2 wrap - 8190lb
3 wrap - 7500lb
4 wrap - 7010lb
5 wrap - 6570lb

So the Warn is rated to pull more with 4 wraps of cable then the 8000lb one is with 2.  Something to look at with a heavy vehicle.  With 4 wraps the Harbor Freight winch is actually under the 1.5 weight recommendation of your 3,800 lb vehicle (5700 vs 5100 pull rating).

You will also need to take a look at the electrical load, to pull with 6000 lbs of force most winches are looking to use 330+ amps of power, so you will need a good battery to take that load.  If you really plan on using a winch you will want a lot of cold cranking amps, dual batteries or a dry cell.  Or a really strong alternator.  I use a dual 6v system on my SJ so I don't have to worry about the load.

Last thing to look at is the price vs performance.  A big fancy fast winch is nice, but for $300 you can get the default harbor freight.  It will pull out you, quite a bit slower then a 2 speed Warn, and will usually never let you down.  If you plan on using your winch a few times a year it will probably be more then enough to satisfy your needs and won't break the bank like a $900 Warn.

With the correct setup you should be able to lift your entire vehicle off the ground. 

This thread made me think of this;

If it can't climb a tree It isn't a Land Rover

(the gods must be crazy)

Funny!

Here's owners' manual info from my SmittyBilt XRC8.

Last thing to look at is the price vs performance.  A big fancy fast winch is nice, but for $300 you can get the default harbor freight.  It will pull out you, quite a bit slower then a 2 speed Warn, and will usually never let you down.  If you plan on using your winch a few times a year it will probably be more then enough to satisfy your needs and won't break the bank like a $900 Warn.

Just FYI, WARN doesn't make a two-speed electric winch. Also, you can get an M8000 all day for $539. 

Just FYI, WARN doesn't make a two-speed electric winch. Also, you can get an M8000 all day for $539. 

Ah, I thought Warn had a two speed winch.  It's just twice as fast, my bad.