Fixing Understeer

Do you know the feeling when the kart just does not want to turn? That feeling is what is known as Understeer. In more technical terms, it is when despite the steering input/steering lock you put in, the kart does not go where you want it to drive. There are many reasons as to why this happens. From driving styles, to setup problems, this article will look to delve into what is understeer, as well as the next course of action is most suitable to take.

 

What Causes Understeer?

Before we give the solution, we must first impart wisdom. There are three major causes of understeer. The first and most common is that the driver simply asks too much from the kart. Having the grip in your tyre (especially the fronts) dictates how much speed the kart can take. Without this grip, the kart will simply veer wide when cornering. This is why tyre management is vital to help a kart make challenging corners, at maximum speed.

 

On the subject of tyre performance, a lack of balance may also have a part to play. While understeer is mainly to blame due to front tyre grip (or lack thereof), it is also important to look at the bigger picture and realize that there is potentially an imbalance between what the front and rear tyres can handle.

 

Another cause that also relates to something in excess is when the driver turns in too much or too abruptly. Again, the available grip is crucial here. If the steering angle caused by turn-in cannot be handled by the fronts, you will slide wide around the corner. Now with all that out of the way, let us take a look at some quick fixes you can make both on and off the circuit.

 

Setup Changes

1. Caster

Source: Praga

 

As mentioned earlier, the lack of front end grip is ultimately what causes understeer. To combat this, one of the first things you can adjust is the kart’s caster. As we can see in the image here, the caster is adjusted through a kingpin bolt. While it cannot be seen in this image as it is lodged deep, the bolt looks like this:

Increasing caster angle can improve the responsiveness of the front end. To do so, it is recommended to increase caster, which is done by moving the kingpin backwards. To decrease grip, simply move the kingpin forwards for negative caster which in turn reduces front grip. It is important to remember as well, that increasing grip in the front reduces some grip towards the rear. This is acceptable due to the fact that the rear wheels of a kart need to lift in order to turn, which can only be done by transferring the weight to the front. However, too much of it can result in a loss of traction and lead to oversteer. There is also the chance as well for the kart to slightly oscillate, so be sure to tread lightly.

 

2. Track Width

Source: TKart

 

The image above shows an arrow which lays out for us the rear track width of a go-kart. With that, we can then see that adjacent to it is the front track width. Either way, both are major components that can help cure understeer.

 

While you will see yourself tinkering with the rear more, adjusting front track width can still give you an edge over the competition. A wider width provides more understeer, so make sure to set the front to be more narrow so that the kart “bites” more during corners.

 

For the rears, always remember that the wider the track width, the kart becomes more pointy, which is what drivers typically aim for to reduce understeer. Having a narrower track width would instead provide more grip to the rears, which in turn produces more understeer in the front.

 

Driving Technique

 

1. Weight Transfer

The underlying theme in all the setup changes we have proposed in this article is its emphasis on weight transfer. Having the weight in the right parts of the kart during certain parts of a track is key.

 

In the case of preventing understeer, the driver’s position can help play a part in weight transfer. Some drivers move slightly forward to add more weight to the fronts prior to turning as this can provide a little more extra grip that the kart needs to make the corner without sliding off.

 

Drivers still want to have good posture in the kart when cornering, but in the rain, will look to move their body weight towards the front tyres as this will help the understeer in the slippery conditions.

 

2. Corner Speed Reduction

We mentioned at the start that one cause of understeer is when the tyres cannot take the demand and speed carried through a corner. So if we put two and two together, it could be a sign that you are entering the corner too quickly.

 

With that, it goes without saying that slightly slowing down the kart on entry may be your best course of action. This is now an opportunity for you to make the most of the speed you can carry on exit instead. Therefore, make sure to position your kart correctly in order for you to shoot out like a rocket on exit.

 

3. Kerbs: The X- Factor

If done right, kerb-hopping can prove to be a viable option when it comes to avoiding understeer and making it through a corner. On top of this, you might even shorten the circuit by doing so! However, do keep in mind that this can come with risks, and the decision to take a kerb ultimately depends on its angles..

 

We can see in the image above is an example of hopping the kerbs done right. Doing so can forcefully get that inside rear wheel to lift as well as providing a little more grip. This maneuver can only be done when the kerb is not too tall and can be run over. If you do happen to run over a tall and large one, this can unsettle the kart and might provide some unnecessary damage that otherwise could have been avoided.

 

The Weather’s Impact

Source: RedBull

 

Before we conclude, it is important to emphasize the major factor that is weather and how this can affect your approach of combatting understeer.

 

On the subject of understeer, there can be instances where a driver leans to the outside of the corner when there is no grip. This lack of grip is exactly present during rainy and wet conditions. Doing so can potentially help in lifting the inside rear wheel which is needed to make the corner and prevent understeer.

 

You may also find yourself making setup changes specifically for wet weather racing. For example, ride height, which is something we did not delve into in this article, is a major adjustment you can make in the wet. Furthermore, drivers also tend to have a narrow rear track width during the wet. This is because it increases grip in otherwise slippery tracks. However, this can also be a factor that paves the way for understeer. This means that in some cases, understeer may be more favorable.

 

These are just some examples that will definitely require you to think twice on what is the best course of action, as well as whether understeer is your enemy or even your friend.

 

CONCLUSION

Understeer can really derail (literally) a kart off the circuit and can cost you dearly at any chance of victory. Therefore, changes must be made. Whether it be subtle changes in driving style such as improving tyre management, or a big overhaul in your kart’s setup in its caster and track width, the point here is that understeer can be managed. Now, it lies in the driver’s hands to figure out what works best so as to avoid this predicament.

 

To elevate your go-kart racing career to the next level, Kart Class has your back! Under the tutelage of a multi-time race winner and Australian kart champion David Sera, a variety of training programs are in store for you. For beginners and champions alike, and even track guides on the most notorious race tracks out there, Kart Class will be sure to take you from the back of the pack and all the way to the winner’s circle!