What is Oversteer and Understeer?, what’s the causes of it and what is the differences between the two!

So, Oversteer and Understeer!, what are they, what is the difference between the two and what causes oversteer and understeer? Lets get started with Understeer first.

So what is understeer you ask?, Understeer is when you turn a corner and the front end of the car gradually goes forward when turning, it usually only happens on FWD cars with a minority of AWD cars as well (like the old Big Audi’s with Quattro for example)

So what causes understeer? Understeer is caused when the slip angle of the front wheels is greater than the slip angle of the rear wheels which in turn causes understeer, slip angle is basically the distortion of the tyres side wall which affects steering.

Understeer Diagram

As shown in the diagram above, Understeer is when the vehicle keeps going forward when turning the vehicle, to reduce the risk of understeer, reduce the speed of the vehicle to regain control, normally Understeer is safer as it is easier to regain control compared to oversteer.

 So what is Oversteer?, Oversteer is when the rear wheels lose grip and throws the car into a slide while going through a corner, this normally happens to RWD Vehicles and some FWD vehicles (Lift-Off Oversteer – essentially when you turn into a corner and let off the throttle the car oversteers slightly instead of understeering)

So what causes Oversteer?, Oversteer is the complete opposite of understeer, unlike Understeer where the slip angle of the front tyres is greater than the rear tyres, oversteer is caused by the rear wheels having a greater slip angle than the front tyres causing the car to slide while cornering.


Oversteer Diagram

As shown in the diagram above, the vehicle turns into a corner and the rear end starts to slide causing oversteer, oversteer isn’t as easy to control compared to understeer (especially if you’ve never experienced it before or if you own a Ford Mustang);) as you need to apply the throttle and turn into the skid to stop the vehicle from spinning out of control and causing an accident.


Tyre Slip Angles


Slip angles are the main causes of understeer and oversteer, as shown in the diagram above when looking at both understeer and oversteer the degrees of the tyres depends on if your understeering (slip angle greater on the front wheels compared to the rear) or oversteering (slip angle greater on the rear wheels compared to the front), hope this write up helped in finding out the difference of understeer & oversteer and hopefully you learned something!

Hope You Enjoy!


From Alex Jebson

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