Unlike other car cables, the
actually spins around, and is used to connect the speedometer gauge on the dashboard to the gearbox, so that when the vehicle moves, the inner cable transmits the rotational speed to the speedometer and provides the driver with an accurate reading of the car's road speed.
Speedo cables can become worn and will eventually need replacing. If you notice the speedometer functioning poorly or 'flickering', there is a high chance that a replacement cable is needed. It is recommended that you use only high quality speedo cables for any car when fitting a replacement.