Linear Steering versus Exponential Steering

To understand the difference between linear and exponential steering, we need to examine three different scenarios with varying cornering approaches.

Scenario One: Fixed Radius Circle

In the first scenario, we have a very thick circle, which is non-optimal. In this case, the steering would follow a specific pattern: you would maintain consistent steering input through the corner, and then if you were to continue on a straight line after exiting, you would simply shoot out of the corner. If you were to do a fixed circle, the steering would be constant throughout, because that's exactly how the car would turn at a fixed radius.

Scenario Two: Closing Spiral (U-Shaped Line)

Instead of doing a fixed radius circle, we can execute a closing spiral, creating an ellipse. In this situation, the steering would progressively increase because we're gaining rotation. We reach the peak rotation at the apex, and then we start spiraling out again on the exit. This creates a U-shaped line through the corner.

Scenario Three: Aggressive Ellipse (V-Shaped Line)

In the third scenario, we use an even more aggressive ellipse, creating an ultra V-shaped line. The steering shape to match this line is significantly different from the U-shaped approach. This creates a distinct exponential steering trace.

Defining Linear and Exponential Steering

Based on these scenarios, we can identify two fundamental steering approaches:

• Linear Steering: The U-shaped line approach, where steering input increases more gradually and consistently

• Exponential Steering: The V-shaped line approach, where steering input builds more aggressively

Downforce and Steering Type

The type of steering you use is heavily influenced by the amount of downforce your car has. If the car does not have any downforce and needs to build up rotation slowly, requiring you to slow down much more before gaining rotation grip, your steering is going to follow an exponential pattern initially.

For high downforce cars, such as formula cars or GT3 vehicles, you're going to have a more linear steering approach where you turn in a little bit faster compared to how slowly and progressively you build up the steering in a low downforce car.

Adjusting Turn-in Point for Exponential Steering

An important consideration when trying exponential steering is the turn-in point. Many drivers make the mistake of only adjusting their steering rate without considering that the turning point is earlier when using the exponential steering approach. The high downforce line starts turning in at a certain point, but when executing exponential steering with a V-shaped line, you turn in way earlier—considerably earlier. Your line when trying this V-shaped approach with an exponential rate should reflect this earlier turn-in point.

The Downforce Spectrum

How much the steering is exponential depends on how little downforce you have:

• Very low downforce: Highly exponential steering pattern (cars like Porsche Cup, GT4, Cadillac V8, and other super heavy cars)

• Medium downforce: Slightly exponential, almost linear (GT3 cars)

• High downforce: Linear or even more aggressive than linear (Formula 1 cars)

• Maximum downforce: Would approach a fixed circle pattern (theoretical, not commonly seen)

The linear steering approach starts a little bit earlier, and everything in between falls within this range. The car would rotate more at higher speeds with maximum downforce, but that's impossible, so we have this range to work within.

Setup and Corner Speed Considerations

Whatever car you're driving, and even whatever setup you're running, you have this whole range of steering speed to experiment with. Remember that a high downforce car on a medium speed corner can be more linear, while in a low speed corner it can be a little bit exponential, though maybe not as much. The differences are going to be very subtle within the same car, but they're still there. The speed you're at will affect how much downforce you have by the time you turn into the corner.

Impact on Trail Braking

The steering approach determines the beginning of your trail braking phase:

• High downforce car: Braking follows a pattern where you brake hard initially, then have a slight reduction, followed by a second step that lines up with the beginning of the steering

• Low downforce car: You start releasing the brakes a little bit earlier as you start turning in also a little bit earlier, which determines the beginning of the U-shaped line