Information Centre - Which Winch

Which Winch? - Some Guidelines to Help You Choose   

Electric winches are far and away the most popular choice for light off-road vehicles up to 3 tonnes or so. This is often because they are easy to fit, reliable, powerful and simple to use. They are also generally more affordable.

What size winch?

Getting the right size winch for your vehicle is crucial. Whilst you can't have too much power, up to a point, and you don't want to spend more money than you need to, either. Weight and dimensions are also a point to consider on some higher capacity winches.

What do the terms mean? 

Just as motor manufacturers quote the very best possible performance figures for their vehicles in their literature, winch manufacturers quote the maximum possible line-pull for their winches. 

Quoted line-pull figures are calculated on the assumption of a bare drum (so the gearing effect is most advantageous). Approximately 10-12% of this figure is lost per layer of rope on the drum. The quoted 'Maximum Line Pull' is actually the maximum load that the winch will lift vertically, (although no 'winches' are safe to lift with). They use this figure as it is the most accurate way of comparing winches. For off-road vehicle recovery  you will need to consider other factors such as a soft ground surface and  gradient.

The Science Bit

The following information explains how to calculate the effort required from a winch in order to judge which model would be best for your purposes.

There are three factors to consider: Ground Condition = GC, Gradient = GR  and  Vehicle Weight. 

First calculate the ground condition (GC). This is numbered from 2 to 25 as shown below.

Type of Ground Ground Condition (GC)
Smooth Road 25
Grass 7
Hard/Wet Sand 6
Gravel or Soft/Wet Sand 5
Loose/Dry Sand 4
Shingle 3
Soft Clay or Mud 2


Now take the weight of the vehicle, say 2 tonnes, and divide this figure by the estimated GC figure. This results in the Rolling Resistance (RR) figure. For example, if the ground is soft mud it will be divided by 2, giving an RR of 1 tonne. The angle of the slope also has to be calculated and added to the RR. Even a vehicle on the flat will have a GR figure as it will have sunk into the mud. For a gradient up to 45 degrees the GR is calculated as a sixtieth of the vehicle weight. Anything over that angle and the GR would be taken as equal to the Vehicle Weight.

Example: If a 2 tonne vehicle is stuck in soft mud up to the axles (i.e. the slope is 30 degrees), the force required to recover it can be calculated as follows.

Rolling Resistance = Vehicle weight divided by ground condition i.e. 2 tonnes divided by 2  =1 tonne.

To calculate the gradient resistance take the weight of the vehicle multiplied by the slope. i.e 2 x 30 = 60. As this is less than 45 degrees it is calculated as a sixtienth (divide by 60). So, the GR is 1 and the force required is RR plus GR, in this case a total of 2 tonnes.

It is wise to include a safety factor at the end. This is one quarter of the total (RR + GR). So the final total is 2.50 tonnes. It is sensible to round up the total figure, say 3 tonnes in this case.

Other considerations when choosing a winch:

Winch weight
The extra weight of a winch system along with its fitting system adds around 90 kilos to the front axle of the vehicle. This is based on a 9,000 lb electric winch with 31metres of wire rope. This obviously has an effect on the likelihood of bogging the front axle. It is worth bearing the weight issue in mind when choosing a winch as this weight can become excessive with some systems. It has to be said that the weight of hydraulic systems tends to be higher, as there are more components and there is the weight of the hydraulic reservoir to consider. One way of keeping the weight down is to use a Plasma 12 winch line. These are only a fraction of the weight of a wire rope which usually weighs 10 or 11 kilos.

Speed
Although high-speed is usually not always a desirable feature, particularly during tricky recovery operations, it is sometimes useful to have the capacity for a good line speed. If necessary, line speed can always be slowed by the use of a pulley block carrying out a double-line pull. This slows the line speed by 50%. It is always possible to slow a fast winch but you can't speed up a slow winch. Some hydraulic winches have two speeds but use of the higher speed reduces line-pull capacity dramatically.

Cost
There is no doubt that an electric winch system is generally much less expensive to buy than a complete hydraulic system with associated hydraulic pump, fluid tank and pipework. This is mainly due to fact that there are less components in an electric winch system. Repair costs are also usually less. Electric winches basically comprise of a gearbox, drum and motor. It is unusual to have problems with the drum or the gearbox unless the winch has been neglected.  The repair or replacement of an electric motor is generally much less than the repair of a hydraulic motor which is made from precision components which are more costly to produce. If necessary electric winch repairs can often be carried out in the field. Though in fairness, hydraulic winches are generally very reliable and long-lived if maintained according to the manufacturers guidelines.