All About Winches
Of all the different properties of a given winch, the line pull rating is the most important. It is the maximum static load the winch can exert on the cable. This will be achieved on the first wrap of the cable on the drum. For every successive wrap of cable on the drum the winch’s torque decreases 12%. This must be taken into account when selecting a winch for your 4X4. A good rule of thumb is to pick a winch that can handle at least one and a half times the weight of your vehicle.
The line pull, line speed, and current draw (applicable only to an Electric Winch; a Hydraulic winch does not have this problem) indicates when a weight of X lbs is pulled, it will be pulled at Y ft/min using Z amps. These numbers vary widely from winch to winch. They should be an important consideration in a winch purchase. It is best to ask an experienced winch owner with a vehicle similar to yours to determine what is best for you.
Weight is an indicator of the construction of the winch. Winches must be very STRONG. Too little weight means too little metal used in the construction. Too much weight could mean that your front end will sag. A benefit of the Hydraulic winch is that it does weigh less, however a draw back is that your engine must be running in order for the hydraulic winch to work.
There is a lot of confusion about the new synthetic winch lines. These are basically a new type of nylon rope that is capable of carrying a strong line rating. Some benefits of a synthetic line is that they have practically no line energy in case of breakage, that they are lighter, not prone to kinks or bends, and they are not prone to having loose strands that are the cause of injury like their steel counterparts. Some negatives are the cost and that they wear a lot faster, especially when used unprotected over rocks.
GENERAL QUESTIONS AND ANSWERS
Q. How do I select a winch for my vehicle?
A. The most important thing to consider when selecting a winch is whether it is capable of pulling 1.5 times the gross vehicle weight (GVW) of your vehicle (donâ€™t forget to take into account that 12% drop in pulling power for every extra wrap of cable on the drum – a 9000lb winch has a line pull of approx. 7000lbs on the third wrap). GVW is the real world weight of your vehicle, i.e. fully loaded. So fill up your fuel tank, load up all those off-road goodies, tools, hi-lift jacks, people and go get your vehicle weighed.
Q. What do the different winch gear systems mean and what difference will they make when Iâ€™m operating them?
A. There are three common gearing systems, worm gear, spur gear and planetary gear. They all do the same job, gear down the high speed motor to a low speed high torque winch drum. The gear reduction ratio is by how much the motorâ€™s output revolutions are reduced for the spindle. The greater the reduction, the more revolutions the motor has to turn for one spindle revolution and the less the motor has to work for that revolution. The difference in the gearing systems is mainly in their transfer efficiency.
The worm gear has a transfer efficiency of 35-40%. This causes the winch to be self-braking even under heavy loads, but this means the unit will need a clutch mechanism for free spooling. Worm gears offer the most reduction, very high reliability, built-in braking mechanism, and generally a slower winching speed.
The spur and planetary gear systems have efficiencies of 75% and 65% respectively. This means they have a tendency to free spool when loaded, therefore a braking mechanism is needed. Planetary gears are the most common and provide both strength and smooth operation with good resistance to torque loads. Only the WARN M8274 has a spur gear due to its different design characteristics.
Q. Iâ€™ve noticed while looking through the manufacturerâ€™s catalogs that thereâ€™re different types of electric motors. What is the difference between series wound motors and permanent magnet motors? Is one better than the other?
A. An electric motor basically has two major parts, the stator and the rotor (or armature). It is the job of the stator to produce a magnetic field which will cause the rotor to rotate when an electric current flows through it.
In a permanent magnet motor, the stator uses permanent magnets. This means the current drain on the battery is lower than series wound motors (which uses field coils in the stator). Permanent magnet motors are good for light and medium duty winches, but winching time and load has to be carefully monitored as they tend to overheat. Series wound motors are used in heavier duty winches, but tend to cost more.
Q. Will my electrical system cope with the extra load of an electrical winch?
A. I doubt it, unless youâ€™ve already hooked up a portable welder. Running a winch is the equivalent of moving your truck on the starter motor! Installation of a winch requires the beefing up of the electrical system. You will require a heavy duty (high output) alternator, capable of at least 100 amps (remember to consider alternator output at idle too, these figures can differ wildly, especially on older models). Fit a high capacity battery, or consider a dual battery set-up with some sort of electronic battery management system. If you have other high power devices, sound system, lights etc, you may want to consider a separate high power wiring loom. Also in case of an emergency install an easily accessible emergency power cut off switch and resettable circuit breakers (the winch cables carry enough current to weld 0.25â€ steel plate).
After you have got power to the winch you will need to get it back to the battery. Ensure your grounding system is capable and all connections are clean, this is where most systems waste power. The best grounding systems will use large diameter cables (such as welding cables), the battery negative post connects to the engine block, the alternator ground connects to the engine (usually through its case) and then the frame is connected to the engine using a grounding strap. Remember, compared to your vehicles other electrical components, winches draw huge amounts of current and can completely drain your battery or overload your alternator in a matter of minutes.
Q. I want to be able to winch from either the front or the back of my vehicle, are the receiver mounted winches any good?
A. Receiver mounted winches are very useful, but remember their static pull load is limited by the receiver they fit into. For a class III hitch that is 5000lbs. This is really only suitable for downsize vehicle and jeeps.
Q. When I buy my winch, what comes with it, and what else do I need to start using it?
A. Most winches come with nothing, but some places do a deal which includes the remote cable control and fair lead hawser. You will also need the mounting kit for your vehicle. I strongly recommend you buy the winch manufacturers kit. It has been designed for that winch and vehicle with all safety aspects considered. Home made winch mounts are disasters looking for a place to happen.
Your winch will now work, but it is limited to straight line pulls between two vehicles. The addition of the following items will greatly increase your winchâ€™s usefulness – Tree saver straps (never wrap a cable directly round a tree, you will kill the tree and kink your cable), a couple of clevis pins, snatch blocks, a choke chain and of course thick leather gloves. Attach tow hooks to the frame on all four corners of your vehicle, and never weld tow hooks on. Use only grade 8 or better (stronger) hardware to mount tow hooks.
Q. What safety equipment will I need?
A. You just need your leather gloves and common sense. Never handle the cable with bare hands, a frayed cable can cut skin to the bone. The most common winch accident (according to WARN, so I believe it) is getting your fingers caught in the cable as the last of it winds onto the drum. Always use the remote control cable when winching, and keep every one out of range of the cable.
Q. What other safety considerations are there?
A. Be aware that a broken winch cable can have enough force in its whiplash to cut through a vehicleâ€™s roof and windshield. Imagine what would happen if the cable met a person. A cable that hits a small tree will tear the tree down. A cable that hits a large tree can wrap tightly around a tree so a person behind the tree is not necessarily safe. Solid objects such as hooks and snatch blocks will fly through anything, including a vehicleâ€™s hood, if a cable breaks. People should stand well out of range of the cable and never in line with the cable. Furthermore, if a cable breaks, the vehicle being winched may roll downhill, so never stand downhill of any vehicle being winched. There are many line weight bags available, but a pair of socks filled with dirt and tied together works in a pinch. Adding a weight bag to the winch line absorbs much of the lines energy in case of breakage.
Q. Is it common to break a winch cable? Should I carry a spare?
A. No to both questions. A properly maintained cable is very reliable (see question about maintenance) and carrying a spare will only increase the risk of damaging it. Winch cable is aircraft grade cable and has a breaking strain of 32,000lbs – much higher than the capacity of the winch. It is much more common for snatch blocks and anchor points to break because they were poorly rigged up. It is a good idea to drape a heavy cloth jacket over the cable to limit the whiplash if something snaps. If someone has to steer the vehicle being winched, then raise the hood for extra protection. Ensure all anchor points are firm.
Q. Is my winch maintenance free?
A. Although many people seem to think the answer to this one is yes, the answer is really no! I have met a number of people in the mountains stuck, with a winch that wonâ€™t work. A little care and preventative maintenance would have ensured its reliability. Your winch should be maintained on a regular basis. Lubricate all required points, inspect all mounts, pulleys, straps and clevis pins, check they are not damaged, or showing signs of fatigue, and are free of moisture. Inspect your remote control lead and electrical system for damage and chaffed insulation. Make sure all terminals are corrosion free and tight. Spool out the cable after each trip. Check for kinks and frayed strands (damaged cables should be replaced). Lubricate cable with a chain and cable lubricant (normal grease will collect dirt) and wind back onto drum.
Q. What does using a snatch block achieve?
A. Basically it doubles your available pulling power (in fact itâ€™s an increase of 85% after safety considerations). It will also allow you to perform pulls at an angle to your truck. People are rarely considerate enough to get stuck straight in front of you.
Q. When I double up the winch line using the snatch block, where should I attach the return line.
A. If the snatch block is attached to another vehicle, which you are trying to free, then the return line should be connected to a third vehicle or tree, to spread the load.
If the snatch block is anchored to a tree and you are trying to free yourself, then the return line should be hooked onto your vehicleâ€™s frame. DO NOT hook it back on to the winch mount as this will effectively double the load on the mounting plate.
Q. What is the best way of anchoring my vehicle when Iâ€™m trying to winch another vehicle out of trouble?
A. Anchor your vehicle to another vehicle or any other fixed object using your tow strap, tree saver, choker chain etc. The one thing to remember is attach the anchor strap to your vehicle at the same end as your winch, otherwise you will stretch your vehicleâ€™s frame.
Originally prepared by Steve Williams in June 1993, and has been updated by The Off-Road.com WEB PAGE February 1996 with additional information provided on Hydraulic Winches.