Steering Linkage for Vehicle With Independent Front Suspension

 In case of conventional rigid axle:

 

• The main axle beam ensures the movement of stub axle in the horizontal plane only

• Therefore, there is no vertical deflection of the suspension and hence there is no change 

  in effective track rod length takes place

 

In case of independent suspension:

   

• The two stub axles can move up or down independent of each other 

 

• Due to which distance between ball joint ends of the two track rod arms is continuously 

  varying 

 

• On account of this a single track rod as in conventional system discussed earlier, cannot 

  be used

 

• Above difficulty is avoided by using steering linkage for independent suspension 

 

• Here three piece track rod is used, the centre portion being called the relay rod 

 

• Relay rod is connected at one end to an idler arm supported on body structure and to the 

  drop arm of the steering gear at the other end through ball joints  

   

• The relay rod is restricted to move in horizontal plane only 

 

• Movement in vertical plane is provided by the other portions, i.e., the tie rods about the 

  end  ball joints

   

It is popularly used in 

 

• Cars 

• Most of the light vehicles