Over the course of a track weekend, if we’re driving at the limit of adhesion of the tires, we’re going to encounter some oversteer or understeer. Here I’ll describe some simple and easy adjustments we can make at the track to both the car and the driver in between sessions to help correct for these handling issues.
Tires Tell the Story
Before we get started it’s crucial that we understand what the tires are doing. We learn this primarily through taking tire temperature during a hot session. In a previous video we provided details on how to properly take tire temperature.
Understanding the Handling Issue
All the adjustments provided are easy to do at the track. Some scenarios to keep in mind:
- Does this happen in one corner only?
- Does it happen only turning in one direction?
- Is the issue consistent or inconsistent?
If the issue occurs at one corner only it is most likely the driver and the driver needs to make some adjustments to alleviate the handling issue. If the issue happens on left or right turns only it is most likely a setup issue and the cross weight is not set at 50%. If the handling issue is inconsistent and varies from corner to corner it is most likely the driver and the driver needs to make some adjustments.
First we’ll look at understeer. A most common issue is understeer on corner entry with steering input. First make sure the driver is not braking too hard and too late. This is mainly for newer drivers. The driver can try braking a little sooner and release the brakes more smoothly. Slow in, fast out is the adage.
If the issue remains, weight needs to shift to the front tires sooner to load the front tires. You can increase front shock compression or increase rear shock rebound. Or you can decrease front tire pressure. Some semantics, increase means to make the shock stiffer so it responds quicker, decrease means to make the shock softer so it responds slower.
Car understeers mid-corner under maintenance throttle
- If rear tire temperatures are too low, stiffen the rear sway bar or increase rear tire pressure.
- If your front tire temperatures are too hot, soften the front sway bar or decrease front tire pressure.
- If this happens in high-speed corners only look to make the adjustment with aero.
Target Heat Range for a DOT-R Rated Tire
The target heat range for a typical DOT-R rated tire is between 180 and 200 degrees Fahrenheit with not much more than a 20 degree Fahrenheit spread across the tire surface, inside edge to outside edge. See our previous video on taking tire temperature and how to do this properly.
Car understeers on corner exit while releasing steering input
- If had corner entry understeer the corner exit understeer is most likely a result of this. Fix the corner entry understeer first.
- If understeer was induced on exit, weight needs to shift to the rear tires at a slower rate. Decrease front shock rebound or decrease rear shock compression.
- Car oversteers in corner entry with steering input – Could be caused by excessive trail braking. Modify the driver and have the driver adjust his or her initial brake point to brake sooner so there’s a transition to throttle sooner. If the issue remains weight needs to shift to the front tires more slowly. Decrease front shock rebound or decrease rear shock compression.
- Car oversteers mid-corner on maintenance throttle – Driver may have thrown the car into the corner to get through an initial understeer condition. Fix the corner entry understeer first. If rear tires are too hot soften the rear sway bar or decrease rear tire pressure. If your front tires are too cool stiffen the front sway bar. If this happens in high-speed corners only look to make the adjustment with aero.
- Car oversteers on exit while releasing steering input – Weight needs to transfer to the rear sooner. Increase front shock rebound or increase rear compression. If you notice the issue in turns going in one direction only make sure your cross weight is 50/50. A positive cross +50% will make right turns easier but tighten up turning left. A negative cross -50% will make left turns easier but tighten up turning right.
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