ASR on a Car Explained



ASR on a Car Explained

ASR is a type of traction control and means ‘Anti-Slip Regulation’. By use of wheel speed sensors located at each wheel, ASR automatically activates every time one or both wheels slip, or ‘wheelspin’ occurs.

ASR helps to eliminate wheel slip by different methods. If for example both drive wheels are slipping, ASR will intervene by reducing engine power until the point that traction is gained. If only one of the drive wheels is slipping, ASR will intervene by automatically braking the wheel that is slipping.

In this instance, ASR is beneficial when accelerating from a stationary position, this could be pulling out from a busy junction for example. The car might otherwise spin its wheels and make little progress into the road. This is particularly prevalent on a wet, slippery road.

ASR is also beneficial when cornering where slipping of the inner wheel occurs. This could be due to excessive acceleration, slippery road conditions or variations in the vehicle load affecting the yaw of the vehicle. Yaw is essentially where the vehicle weight shifts from its center of gravity to either the left or right and the car ends up heading in a different direction than it’s pointing.


ASR Off Button

ASR is featured on certain car makes and models such as Fiat 500, Skoda, Mercedes, VW, Audi, Isuzu, Alpha Romeo. You may notice on your dashboard or center console an ‘ASR OFF’ button. Press this button to deactivate ASR. But should you switch off ASR?

ASR On or OFF?

For the average driver, you’ll almost certainly want to leave ASR on and activated. ASR is on and activated at each ignition cycle / every time the car is started and you cannot permanently switch it off. You should only switch ASR off if:

  • Your car is stuck in snow or mud. ASR will prevent wheel slip which on certain conditions can hinder you. Wheel slip may help you to gain enough traction to ‘rock’ the car backwards and forwards to free you. Wheel slip may also prove beneficial by allowing the tires to dig down enough to find a solid surface.
  • You’re racing the car. ASR can hinder performance due to the system reducing engine power or automatically braking the wheels when it activates. However, switching ASR off is only beneficial to a driver who has a high level of control over the vehicle and understands where the vehicle limits are.