Motorsport Engineering – Understeer and Oversteer
Most general racing enthusiasts will know what understeer and oversteer is.
Understeer is to do with the front wheels of the vehicle and means that they don’t want to turn at the same rate you want to. This can be caused by going to fast in to the corner, or not having enough grip for a corner.
Oversteer is when the rear of the car does not want to grip to the track generally caused by pushing relatively hard or to fast through a corner or forcefully applying more acceleration than needed. This will cause a sideways action that is not generally the most comfortable feeling in a car.
Below on the left is understeer, and the right is oversteer
Generally in wet conditions understeer is a very big feeling you get in a race car. As the track is wet, and slippery, it creates the perfect environment for understeer.
One thing a lot of people have happen when racing, is they get turn in understeer, exit oversteer. Which means they get understeer into the corner and oversteer coming out. This happens as a result of not being able to turn the car into the corner and reach the apex and then trying to compensate by getting on the throttle earlier than normal. Another reason this happens is traveling to quick into the corner (as mentioned above) therefore getting understeer, then when you finally get the car to a speed where the tyres can grip, the car starts turning at a rate more than the car can handle and that in turn creates the car to slide into oversteer.
Albeit very old, take a look at Larry Perkins oversteer slide. Helped by Mark Larkham behind him, this demonstrates oversteer perfectly.
While neither of these handling characteristics are ideal in a racing car, most people prefer the undertseer method as it is a little more comfortable and sometimes easier to get around than oversteer. I myself enjoy a car that oversteers more, but that’s just personal preference. Both of these will contribute to a lot more tyre wear as well. Sliding tyres across the ground will also create more friction in the tyre and therefore create more pressure built inside as well as temperature. Now when you are using pressure and temperature to try and get a good handling car, you don’t want to go out and destroy your session by getting false readings by having to much understeer/oversteer. It’s a game of balance. What is giving you the best result?
If you want to know anything specific about motor racing or setup, let me know in the comments below and I’ll try my best to work on a post for you!
Yours in understeer and oversteer,
Lee.
