In rallying, the only consistency is the inconsistency of the surface. This constant uncertainty can thoroughly challenge a driver’s ability to choose the proper line through a corner.
It’s a mental battle between ending up too fast into a corner resulting in frantically gathering it up on the exit or slowing down too much realizing it could have been taken faster.
So then, how do you choose your line? It comes down to your best educated guess based on what you see in the surface and what your pacenotes tell you about the corner.
Despite this feeling of improvisation, there are some general rules of thumb when it comes to choosing a line.
First is to start with the rally late apex line. This is the idea of squaring off the corner as much as possible.
It follows a line that enters on the outside and then exits on the inside of the corner. Think outside to inside. This is in contrast to the typical early apex line (outside-inside-outside) that is followed on circuit track driving.
The inconsistent grip in rallying means we need to simplify the job we are asking the tires to do. They don’t like to multitask, and there is only so much traction available. A driver needs to be conscious of how much they are asking of the tires. Rally tires grip best in a straight line. So, the rally late apex is designed to maximize straight lines into and out of the corner. This simplifies what we are asking the tires to do in any given moment. The tires are either braking, turning, or accelerating, but not all at once.
This late apex approach allows the tires to focus more of their grip on turning resulting in a quicker rotation in the corner. Time spent turning is time lost accelerating to the next corner.
This type of line approach has a secondary benefit. There can’t be the expectation that the grip exiting the corner is the same as entering the corner. By aiming to exit the corner on the inside, the driver has some wiggle room to collect or save the car should the surface throw them a curve ball. If the driver hits a slick patch on the exit which forces the car to slide wide, at least there is still some road width left to save the car. If the driver had aimed to track wide on the exit in the first place, well now they might be out of luck in the ditch. Your line through a corner needs to leave room for the margin of error and the inconsistency of the surface.
Another general rule of thumb is to go where the grip is. Which conveniently, or confusingly, might mean deviating from the late apex approach.
The surface in rallying is extremely dynamic. The gravel moves around. At the beginning of a rally, the gravel will have a loose slippery top layer. Think of marbles on a kitchen floor. A late apex line may be appropriate in this scenario.
However, as the rally progresses, competitors dig into the loose top layer flinging gravel off the road. The available grip will change. Grooves and swept patches will develop in the road’s surface. These areas should provide more traction since the grippier base layers of the gravel have been exposed. The marbles have been swept from the kitchen floor now providing more traction. If the driver follows a line that puts the tires in these areas through the corner, they will have more traction for braking, cornering, and accelerating.
This could mean modifying the late apex line approach. This may take some creativity. All of this counts for naught if you don’t see the where the grip is ahead of time.
A good rally driver uses their vision to not only see where they want to be going, but also to read the surface ahead making predictions about the grip levels. Your vision is key to choosing the best line through a corner.
Utilizing your vision and your understanding of the available traction from the tires and the surface allows you to approach the corner with at least half of a plan. After that, it’s a game of improv. Be adaptive and stay creative.