Imagine that we're doing a 180 degree corner so pretty much like a hairpin but a long one so we spend a lot of time under braking here. Initially we're braking hard on a straight line for long duration. Here we are creating a force that is totally against the speed of the car because we are only braking we're not turning at all so the car is going that way we are creating a force opposite of the direction of the car. This force actually matches the direction of the exit.

Force Vectors During Corner Entry

As soon as we start turning a little bit, we are creating two directions of forces. One is still backwards and now we're creating a little bit of a force to the inside. The car is already going in a direction that's not parallel to the entry anymore. When you combine those two forces you will get a resultant force which also matches the direction of the exit force.

As we progress through the corner and reach the point where we are already turning a lot and still braking pretty heavily, the car is moving in a specific direction. We're creating a force against that direction with the brakes but it's not that much anymore, so the braking force becomes smaller. However, we're turning a lot more now. Again, if you get the combination of these two forces it matches the direction of the exit. This is ideal.

Peak Rotation and the Transition Point

When we reach peak rotation at the very moment where we accelerate, this is peak lateral grip. At this point we have a lot of rotation because we're transitioning from a tiny bit of braking to a tiny bit of acceleration. This force at peak lateral rotation also matches the exit direction. This is what we want because in the end we want all forces to be pointing down the exit direction.

What Happens When You Accelerate Too Early

If we were earlier in the corner and decided to accelerate, we would create a force in the acceleration direction and we're turning, so we're creating a force in the turning direction. The combination of these two forces creates something that does not match the exit direction that we wanted. You are going against the end goal which is getting to the exit as fast as possible. That is the reason in a corner where we're on the limit all the way we should never accelerate towards the opposite direction of the exit.

What Happens When You Brake Too Late

Similarly, if you were further into the corner and realize that you're going wide and start braking, now you're braking and you're turning in a specific direction and the final forces are not matching the exit again. This is really bad.

The 50 Percent Rotation Rule

In the end the transition of the forces should have the final forces always matching the direction of the exit. In this situation you can realize that the point of acceleration in a corner that is 180 degrees is at least when you have rotated half of that which is 90 degrees.

This is a great baseline for finding our MRP on a corner where you need to decelerate to be able to do it. You have to rotate at least 50 percent by the time you start accelerating. This is a great baseline to help you find the ideal lines on a corner when you're just learning the track or learning the car.

Understanding Early Braking Forces

What about the early part of the corner where you're actually braking but the direction of the exit is at a significant angle? We're creating a force that appears to be way against it. However, there's a difference here because we need to decelerate the car in order for the car to be able to create the lateral forces. If we don't create this deceleration right now, the car is going to be too fast and it's never going to be able to create the required force later in the corner.

These forces start to make sense as soon as we get into the workable speed range, but if we're too fast it's not going to work. In this case we're creating a force that does not match the direction of the exit because we need to decelerate the car to be able to do the correct forces later in the corner.

Never forget the rule: the car has to rotate at least half before we get back on power.

Applying the Baseline

This is a baseline. Of course there will be differences based on:

• The car

• The setup

• Whether you should hit curbs

• Elevation changes

• Camber changes

But this is a baseline when you're learning and figuring out where your MRPs are. This is a great baseline to turn half of the corner on the braking and the second half while accelerating. That means we need to achieve the required rotation before starting to accelerate, which is way before the apex. We're starting to accelerate very early because the car is pointed early, but we did rotate 50% into that corner.

The Function of Trail Braking

In the later part of corner entry where we're still braking, this appears to be really against the direction of the exit. However, there's a reason for this. The tiny amount of braking being used is actually shifting weight to the front tires and amplifying the rotational forces. In a way, creating this tiny bit of force that goes against the direction of the corner is actually making the car create a higher force that matches that exit force.

This force is amplifying the effectiveness of lateral grip, making the car point more towards the direction that we want. In the end it's physics: we're always creating as much traction as possible towards the direction of the exit.

When Braking Is Not Necessary

If we're doing a corner where the car is already on the speed that it's capable of taking all the lateral forces needed to do that corner, then you don't have to brake at all because the car is already capable of creating those forces. In that case, you can just do it flat.