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Oversteer, Understeer, and Neutral Steer 101

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Figure: Oversteer and Understeer


Understeer on the left. Oversteer on the right.


Understeer is the term used to describe when the front tires have less traction than the rears, and regardless of your steering corrections, the car continues "plowing" or "pushing" straight ahead to the outside of the turn. Think of it as the car not steering as much as you want, so it is "understeering". Understeer, in effect, increases the radius of the turn that the car is making.

Accelerating too hard or not smoothly enough through a corner transfers excessive weight to the rear, decreasing traction at the front and causing understeer.

Most drivers' first reaction to understeer is to turn the steering wheel even more. DO NOT DO THIS. This increases the problem because the tires were never designed to grip the road at that Angle x Speed! The tires were meant to face the road with their full proile, not with the sidewall. So the tire's traction limit will now be decreased more by further turning the wheel.

To control understeer, decrease the steering input slightly and easy of the throttle gently to transfer weight back to the front of the car. This increases the traction limit of the front tires all while reducing speed. Once you have regained front tire traction and controlled the understeer, you can then begin squeezing back on the throttle. Obviously, this easing off and getting back on the throttle will destroy your speed on the following straightaway and upset the balance of the car but it is better than plowing into an outside wall or going for a ride in the sand pit.


Oversteer is when the rear tires have less traction than the fronts, the back end begins to slide, and the nose of the car is pointed at the inside of the turn. The car has turned more than you wanted it to, so it has "oversteered". This also called "being loose", "fishtailing", or "hanging the (insert replacement for ass here) out". Its effect is to decrease the radius of a turn.

Turning into a corner with the brakes applied, or lifting off the throttle in a corner ("trailing throttle oversteer") causes the weight to transfer forward, making the rear end lighterr, thus reducing rear wheel traction. The result? Oversteer.

Also if you accelerate too hard in a mustang or any rear wheel drive car for that matter, it will produce "power oversteer" or "power slide". What you have done is sued up all of the rear tires' traction for acceleration, and not left any for cornering. To control excessive "power oversteer", simply ease off the throttle slightly and it will tend to bring the rear end back in and even out the traction between front and rear.

To use oversteer to your advantage, just look and steer where you want to go. This forces you to turn into the slide, or to "opposite lock", thereby increasing the radius of the turn. At the same time, gently and smoothly ease on slightly more throttle to transfer weight to the rear and, thus, increase traction. Whatever you do, avoid any rapid deceleration. This will most likely produce a spin as you shift more weight forward decreasing rear wheel traction even further.

Neutral Steer

Neutral steer is the term used to describe when both the front and rear tires lose traction at the same speed or cornering limit, and all four tires are at the same slip angle. Sometimes described as being in a "four-wheel drift", this is ideally what a driver is striving for when adjusting the handling of the car and trying to balance it. Personally, I love the feeling when I'm controlling the balance of the car with the throttle, driving through a fast, sweeping turn at the limit. If the car begins to oversteer a little, I squeeze on more throttle to transfer a little weight to the rear; if it starts to understeer, I ease off slightly, giving the front a little more grip. when it's done just right, all four tires are "slipping" the same amount; the car perfectly balanced, neither oversteering or understeering; in a perfect neutral steer attitude through the turn.

In terms of how the car is set up, however, most drivers prefer a little understeer in fast corners as it's a more predictable, safer characteristic; they prefer oversteer in slow corners to assist in pivoting the car around the tight turn.

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If you read any kind of books on performance driving, it will tell you that the fastest way around a corner is 3-5 degrees of slip angle. In plain english your wheels should be turned in 3-5 degrees more inside of the corner in relation to where the car is heading. It keeps the tires sliding just a little bit, keeps them in the proper heat range, makes the rubber compound work at peak performance. When you take that info and dumb it down a little, you will see that this is actually a very slight form of understeer. This is why I'd much rather have understeer instead of oversteer. This does not mean that front end lacks traction, all it means is that rear has more than front. So my perfect way to build a car is to give it as much front end grip as possible. Then, without taking away front end grip (playing with spring rates or sway bars), you give rear end just a bit more. Usually this can be accomplished several ways, including dialing in the rear suspension, and adding rear tire (just enough to overcome front, but not enough to penalize you with too much additional weight).

There are NO instances of oversteer being faster. Any time you are sliding the rear, you are wasting energy. Tires become hot, and kinetic energy lost in wheel spin simply turns into heat rather than forward motion. To go the fastest you must get the most out of front tires, and that's simply not possible when you are oversteering, and controlling the speed with rear tires, by driving at their limit. The one and only time I can foresee oversteer being faster is when the car is physically unable to make the turn. Yes, oversteer is faster than a 3 point u-turn.

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