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Line Pull


Anderzander
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Basic question - how is the line pull of a winch measured?

My winch is rated 14,000lbs, which is 6.25 tons. Is this the weight that the winch is rated to pull without friction - ie if it was lifting the weight?

I know that manufacturers and sellers seem to suggest you should calculate the winch rating by taking the gross vehicle weight and multiplying it by 1.5 - is that to allow for resistance and friction acting against the load?

Stephen

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Generally you should never use a vehicle winch to lift anything as it does not have the safety factor for lifting nor a fail safe mechanical brake, but yes the idea you have in mind is correct - its the load the winch is rated to pull so if you hung a weight off a cliff via a pulley block that would be the same.

It isn't the load at the point the motor stalls which is usually a fair bit more for electric winches. It also isn't the load the winch will pull for very long, not in most electric winches anyway, mechanical and hydraulic are different. It may be hydraulic based propaganda in some people's eyes but there are some interesting test results on http://www.4x4winches.com/index.php?page=winch_test.htm which are worth a read.

Taking the vehicle weight and multiplying it by 1.5 probably isn't enough for most normal electric winches, a factor of 2 is probably nearer the mark which would mean a 2 ton Defender (4500lb approx) needing a 9000lb winch which is about what it does need to perform decently. A 6000lb winch on a Defender is carp. It doesn't mean the line pull is actually 9000lb in most practical situations but it means the winch has the reserve capacity to pull the vehicle a decent distance without going pop.

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Thank you chaps!

I knew they weren't certified for lifting - just trying to give an example of a frictionless pull.

I presume there are some complex maths to work out resistance for different surfaces and gradients - but with my winch being 3x the weight of the truck I should hopefully be fine.

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Your question does, to a small degree, indicate you are not overly familiar with winches and winching technique.

Can I recommend spending a few hours on this site http://www.dborc.co.uk/goodwinch/ and follow the 'Learn with David' link.

I don't claim to be an expert but found the info very informative and there is a section explaining how to work out the required line pull for different slopes and situations.

No doubt someone else will be along to tell us both where to look for more/better advice.

Steve

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The multiple of the vehicle's weight will vary greatly depending on the surface it is on and the gradient as well as lots of unknowables such as the drag within the transmission and brakes.

The line pull is technically as you stated but the manual for the winch will probably state that it will be the first layer of cable on the drum with a certain number of 'wraps' of cable so that the pull is central to the drum and at a certain line voltage on the supply using a particular size of cable in a stated range of operating temperature, etc.

Rely on it in the same way that you might rely on a manufacturers official fuel consumption figure. It means that you might get a bit more in optimal conditions but mostly you will get a bit, or a lot, less.

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The other thing to note is that rumour has it an H14W with the overload valve/clutch removed will pull 20,000lbs. The electricity board ones are often set very low (closer to the lifting SWL if they're used for that) so can cut out before reaching enough pull to move a stuck shopping trolley.

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I wouldn't advise that though, I did mine up as tight as I could get it, then snapped the chain in the PTO whilst dragging a Range Rover up/into a hill. Not an easy situation to get out of as everything locks solid.

Mine was set up as the manual advises and although it seems to cut out quite early I'd rather have it do that than break something again. That said, it's only set to 8000lb (it's a Fairy 525, but PTO and shafts the same as the H14) so I might nip it up a little bit more when I get near the vehicle again...

Richard

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I wouldn't advise that though, I did mine up as tight as I could get it, then snapped the chain in the PTO whilst dragging a Range Rover up/into a hill. Not an easy situation to get out of as everything locks solid.

Mine was set up as the manual advises and although it seems to cut out quite early I'd rather have it do that than break something again. That said, it's only set to 8000lb (it's a Fairy 525, but PTO and shafts the same as the H14) so I might nip it up a little bit more when I get near the vehicle again...

Richard

good to see you back on here :i-m_so_happy:

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