Guys, take a look at the cable load charts below, the 5-1 ratio is for over head use, the 3 1/5-1 ratio is for winch work, this chart is for NEW wire rope with a WIRE core, a fiber core (which our front winches have) cable has less SWL loading then shown, so just because someone has a 45,000 lg , a 20,000 lb, or a 10,000 lb winch, DOES NOT mean you can put this on the cable.
The factor of safety for all fibre ropes is 5. For ropes used to hoist or support personnel, it is 10.
As a example a 45,000 lb rear wrecker winch uses 3/4" steel core cable, it has a breaking strength of 58.000 lbs NEW, so with a bit of use, maybe a bit of corrosion, I can see that 58,000 down to maybe 50,000, now with a bit of OVERLOAD, a bit of rub wear, maybe a minor kink, ect. I can see that 50,000 down to 40,000, with things getting WORSE every time the winch is used, the above example is WHY there IS a SAFE WORKING LOAD (SWL) ratio
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There IS a reason for snatch blocks and one of the MAIN reasons for those double, 3/4" snatch blocks from he11 that the wreckers carry (nothing else has the springs to carry them around)
You want to put a SWL of 45,000 on a winch cable, go to 1 1/4" cable
You SUPER winchers that think that because you have a HIGH pull winch and can/do hook up and pull to the winches MAX ARE going to hurt/kill somebody, tore up iron can be fixed, losing a body part or death CAN NOT
http://www.ingersollrandproducts.com/lifting/winches/wireropechart.htm
Fiber core load chart, notice the difference in the two charts
http://www.engineeringtoolbox.com/wire-rope-strength-d_1518.html