Updated: Mar 31, 2021
Turn-in oversteer is a very common problem we see people suffering from, particularly when moving over from some more casual racers like F1 or Gran Turismo, in this video guide we look at what causes it and how you can avoid it.
As always, you can find the video's full script below in case you would like to read about certain details.
Oversteering - Track Titan guide on why you keep spinning when turning in (full script)
As drivers move from more casual games such as Gran Turismo or the F1 Game series, to more realistic simulations such as iRacing or Assetto Corsa, we see a lot of drivers struggling with something called turn in oversteer. This is where you lose the rear end of the car as you turn in, and you might even end up going into a spin which is obviously annoying.
We're going to talk about the main reason why that happens and then explain what you can do to avoid that going forward.
Let's look at an example of turn in oversteer. So approaching the corner, shifting up the gears, and then we get heavily on the brakes - you can see the moment we turn in the rear just steps out - we're saving it just about there, but you can see losing quite a lot of time because of that.
As you could see in the video braking in a straight line seems to be quite stable, but as soon as the driver starts turning in this is when the rear starts stepping out.
So the question is: What's the issue here? Is it the braking? Is it the turning? Is it the combination of things?
Obviously we told you in our other video trailbraking is good right, we want to keep a bit of weight on the front wheels. However, you could actually overdo that. So let's dive into the physics behind this to understand why braking too much on turning can cause snap oversteer.
The first key point we gotta mention when it comes to braking is what braking does to the weight distribution of the car and how that affects grip. So as you can see in this animation all the car's weight moves to the front meaning we're unloading the rear. As you can see the friction circles reduce in size, so we have much less grip available under braking than in a static scenario.
What that means is as soon as we get on the brakes heavily as we go into straight line braking, we're already maximizing that very little grip that we have in the first place right, and you can see here the arrow goes to the edge of the circle meaning we're using all the grip available for longitudinal forces in this case braking.
That's fine as long as we don't turn in but the moment we start turning in whilst keeping the pressure at the same level, you can see those combined forces actually exceed the friction circle's limits meaning we're asking too much of the tyre, and that's exactly why we lose the rear end.
The good thing is there's an easy way to avoid that problem, that's just coming off the brakes or turning in a bit less. And as you can see by breaking less we actually put more weight back on the rear tyres, we increase the friction circle size so we have more grip, and equally we're asking less of the tyre because we're not applying as much brake pressure.
If you implemented those tips and you're still struggling with turning oversteer under braking you might want to start looking at your brake bias. What does that mean? The brake bias determines how far to the front, or to the rear the brake pressure gets distributed. And if you have too much pressure on the rear you can do whatever you want, you're still going to lock the rear tyres or start spinning because you're just asking too much of them.
So now that we know that by braking we unload the rear which gives the rear tires less grip, let's see what we can do with the brake bias. So if we had the brake bias set to 50/50 (meaning 50 percent of the braking force gets applied to either axis) we'd start locking up the rears quite quickly. Why? Because they simply have no where near as much grip as the fronts.
So if you implemented the tips we gave you previously and you're still struggling with turn in oversteer, take a look at the brake bias. Move it slightly more to the front, and see if that stabilizes your rear end.
In conclusion, there are several reasons why you might struggle with over steering as you turn in, but the main one that we see over and over again is just staying on the brakes too heavily, too deep into the corner. By combining the cornering and the braking forces you're just asking too much of the unloaded rear tyres, which causes you to go into a spin. Equally, if you start implementing that tip and you're still struggling after a while, you might want to take a look at your brake bias.