Positive toe is inward (toe in), negative toe is out.
Toe out on the rear will help induce oversteer. On the front, not sure. I add a touch of toe in to add stability in braking and assume it makes turn in sharper due to the outside tire facing more in the direction I'm turning, could be wrong though.
Good train of thought, but i think you are mistaken with the toe-in = better turn-in premise. This is assuming the inside front wheel is off the ground, however since racecars want to limit weight transfer and roll, the inside tire remains planted on the tarmac and has plenty of weight remaining on it.
A better view of front toe is to look at the plane the centerline of the tires makes perpendicular to the road. So when viewed from above, this plane becomes a line. On a car with toe-in, the lines from the left and right tires would intersect in front of the car because the tires are pointing inward to each other (..//....\\..) This inward facing brings the car to attempt to move each side of the car in toward itself. Likewise, if there is a small steering input (due to bumpsteer or wheel input) the outside tire will move in that direction, but the inside tire will still be trying to move the center of mass inward or maintaining direction (..||....\\..). This geometric property is what give the car stability with toe-in. Since the wheel on the inside follows a sharper radius than the wheel on the outside, it needs to be turned more into the corner than that of the outer wheel. This causes a small amount of scrub which will prevent the car from turning as much. (We are talking fractions of degrees here, not much). It is only when steering the inside tire past its straight position and into the turn, do we get any actual turn-in.
On a car with toe-out, the lines at the centerlines of the tires would intersect behind the car because the tires are pointing outward away from each other (..\\....//..). This is a much more unstable side of toe, and that is why you will only see toe-out in racecars, and not in passenger vehicles. The idea behind toe out causing straight-line instability is actually false, in theory. Any toe will create a more stable environment than no toe because doing so will create opposite forces being applied on the car and will prevent chatter from forming due to tracking of the tires. However, that is only in theory. In practice, we find that toe-out causes some straight line instability whereas toe in does not. We already saw why toe in would be beneficial since you need an amount of steering to get the car to turn. In toe-out situations, that is not always necessary. This is due to the phenomenon of bump steer. An uneven track surface will cause compression in one side of the suspension and not the other. The compressing of the shock will usually cause that side to create a toe-in sensation. This means that both wheels are now turning the same direction, or at least closer to it. You can see how this would disrupt you on the straight. Luckily, if you have toe-in in the rear, which has more of an effect on the car, it will counteract that and give you some stability.
Now let's look at toe-out approaching a corner. Once you begin to even think about steering, the car enters the corner. That is because once you turn the wheel a fraction of a turn, the tires begin to follow their arc around the corner. Since, as we learned before, the outside tire follows a wider arc around the corner, once we turn the wheel a bit, the inside tire turns but the outside tire straightens out (..\\....||..). You can see that if we had a sufficiently wide car, we would actually be following the perfect path around a corner with much less steering input and scrub as compared to the toe-in version. The geometry used to design ackerman steering is the same as with toe-out. This is why it causes quicker turn in.
I think too much, lol
