Tow Truck



No Stacking

Click on the descriptions below to read about the functionalty factors of Equipment

General Description
  • Tow tractors are used for pulling train of trailers
  • General applications include shifting material from one part to another, order picking
  • Tow trucks are classified into 1) small (100 – 500 kgs), 2) medium (250 – 750 kgs), 3) large (1000 – 5000 kgs) and 4) extra large (5000 – 35000 kgs) tractors based on their drawbar pull specification
Towing capacity

The towing capacity of truck is defined by term Drawbar pull. The Rated towing ability of a Tow truck is reduced due to the Gradability and the surface on which it operates (Figure 1)

Deration(Reduction) occurs in rated load capacity due to floor surface. It is caused due to the increase in coefficient of friction between the tires and the floor surface (Figure 2)

Deration(Reduction) occurs in rated load capacity due to increase in incline or slope due to addition extra weight component because of inclined movement of truck (Figure 3)

For flat ground application,

Norma Drawbar Pull = Trail Load X Coefficient of friction

For ground with Gradability,

Normal drawbar Pull = Trail Load X Coefficient of friction + (Vehicle dead weight + Trail load) X Grade

Some Standard Coefficient of friction are as mentioned below:

Road Surface Coefficient of friction
Flat block surface 0.020
Concrete 0.020
Asphalt 0.020
Rolled gravel 0.025
Firm soil or grass 0.035
Firm soil or grass with turf tires 0.030

Towing unit

Tow truck has multiple levels for towing at rear end. The height of the towing unit is responsible for the weight transfer of load onto truck’s drive and steer axle and the corresponding drawbar. The highest towing point offers maximum drawbar pull and lowest offers the minimum pull

Turning radius

The turning space taken by truck to rotate by 90 degree without the load

Aisle Width
Minimum Aisle width: The width of the road/ space between two adjacent shelves is called the aisle width (For safety reasons, the aisle width should be at least 150mm more on each side than the width of load or the truck, whichever is wider).

Minimum Aisle width = Clearance from wall (1) + Width of Truck/ load (2) + Clearance from wall (1)

It is the ability of the truck to travel on slopes/ uphill roads/ inclined surface without a considerable loss of forward speed or drain on the source of the energy. The angle of incline is stated as percentage and is obtained by dividing the increase in height of slope per meter of slope/ road length

Electric motor: 10% (General)

Gradability = Height of slope/ Unit length of slope X 100%

Electric truck Battery selection

The battery selection is dependent upon voltage and Ampere – hour rating. The voltage is related to the speed of the truck. The ampere – hour is related to the number of continuous working hours of the truck i.e. higher the ampere – hour of battery, longer will be the running time. Batteries can be used until 80 percent discharged.

One Ampere - hour is equal to flow of one ampere current for one hour. Thus, a 750 Ahr (ampere - hour) will get discharged at 750 amperes in one hour or 375 amperes in two hours and so forth.

For a standard industrial battery, the running time can be calculated as,

(Ampere - hour rating) X Factor = Running Time
Average motor current                           

For an 8 – hour industrial battery, the factor is 0.95 & for a 6 - hour Industrial battery, the factor is 0.98

*Note: The equation is an approximation for calculative purpose only. The actual running time will depend on many other factors like size of the motor, terrain, driving condition and other specific truck application

Battery charger selection

Manufacturers offer two types of chargers namely single rate and double rate. As the name suggest, double rate battery chargers charge faster than the single rate battery charger. Double rate battery chargers are a little more expensive than single rate battery chargers

For a standard industrial battery charger, the running time can be calculated as,

(6 - 8-hour discharge rate) X Ampere - hour rating = Average charging time
Charger current rating X 0.66                                          

*Note: The equation is an approximation for calculative purpose only. Please refer to the battery charger specification for details.

Parts of Tow truck

The transmission unit or assembly of an electric platform truck consist of direct gearing. Gear drives are efficient but are subjected to shock loading wear and tear

Electric Motor: Electric motors have two variants namely AC motors and DC motors

• Electric trucks are suitable only for Inside operation

• Electric trucks require battery charging station

The front wheels are the drive wheels.

The traction battery is strategically located at the front end of the truck to utilize the force of its weight on the front drive wheel and ensure sufficient traction even when the truck pulls at full load

The rear wheel acts ac the pivot during turning of the truck