hi i was just wondering, what is understeer and what is oversteer?

 

Understeer is when you are taking a turn: You turn the steering wheel but the car doesn't respond because it has lost traction. Although the wheels are pointed to the way u wanna turn, the car keeps sliding forward.

Oversteer is the same concept except you turn the wheel, the car turns alot more than expected.

 

Here's one way I think you'll find the easiest to understand;

Understeer and over steer both happen when taking corners fast.

Understeer
The front wheels lose grip, so, say in a left turn, your car goes wide, and you have to turn the car more left to compensate. Hence, the car is understeering. You can reduce or stop the understeer by;
1) Turning more to the left, more into the turn.
2) Braking. The force of braking will push more of the car's weight onto the front wheels and make them grip more, reducing understeer.

Oversteer
The rear wheels lose grip, so in a right turn, the cars starts going more right than you want it to. The car is over steering now. You can compenstae by either;
1) Turning slightly to the left, opposite of where the car is going.
2) Accelerating. The force of acceleration will push more of the car's weight onto the rear wheels and make them grip more, reducing oversteer.


Most cars nowadays are built to understeer from the factory because in a panic, most poeple hit the brakes, which is what you are supposed to do in an understeering car.

DW

 

am i right when i say that understeer is most common in fwd cars while oversteer is most common in rwd cars?

 

You can make either one of them do either, but for the normal scenario that's a safe statement.

A simple explanation on the terms: Understeer = Scared Driver, Oversteer = Scared Passenger

 

Oversteer is what I'm used to and what I know how to compesate for in a rear wheel drive car. Hard corner=backend coming loose and you steer into the direction of the slide.(FUN!)Had LOTS of HiPo cars that were rearwheel drive, and the reaction to me now is intuitive, (example is Z28 Camaro...rear breaks traction and you steer into the slide...) however in a frontwheel drive car this is scary to me. I've never had it happen because I am careful not to. (the Maxima comercials love to show this move.....rearend coming loose and then sliding to a stop)I really don't know how to handle this in a frontwheel drive. Can someone explain? Is the reaction of the driver supposed to be the same as a rear wheel drive? or are the techniques different?
TIA
2maximas

 

That can kinda work if you catch it soon enough, though not as well as you're used to. The critical thing to remember is don't lift.

 

The thing with oversteer in a RWD compared to a FWD, in RWD config, you have more weight in the back, so the car will tend to reach oversteer more gradually, and in a more controllable fashion. You can make a Maxima oversteer, too, but since it is so light in the back, the onset of oversteer is more abrupt, and tricky. I had my RSB and I set the car to oversteer by making my rear tire pressures high, like >38 psi, and the over steer would happen, but too fast. Not good on the street. Now it's set to be just behind the front, the car 1st understeers, then follows with oversteer, much more manageable.

DW

 

im not too sure, but i dont think accelerating while experiencing oversteer would help. best thing ive found to do is countersteer and just get off the gas, or brake while countersteering, i think giving more gas while the car is trying to turn into the apex would just cause the car to spin out. Also if u are on the threshold of traction while understeering, braking wouldnt be the best idea, as u would most likely break the traction threshold, and just slide, althought out ABS would take car of that for the most part. If u are experiencing either understeer or oversteer, turn away from the direction the car wants to go and decelerate, not necessarily brake, cuz that could make things worse, and giving more gas could make things worse.

 

Ummm

I think I see what you may be getting at. From what I said before, some people would think to either brake, or floor it. I guess I should add that letting go of the accelerator has the same effect as braking, but more subtle. Also, pushing the throttle gently (accelerating) is the same as flooring it, but more subtle.

BUT, what you are saying is not right.

In an oversteering situation, letting go of the throttle is a VERY bad idea. You will only make the car oversteer more.

In an understeering situation, not braking, but counter steering may help, as I mentoned before, but so will stepping on the brakes, also as mentioned before.

DW

 

hmmm
time to do some testing on GT3

 

...it all has to do with traction. Your car essentially does three things - accelerate, steer, and brake - and they all need traction. If you're understeering or oversteering, you're using close to 100% of your available traction in steering. You sure as hell don't want to even think about accelerating and braking might make things worse.

In an understeering situation, the front end of your car is losing traction and wants to move to the outside of the turn. If you're understeering severely, counter-steering may not be possible and might de-stabilize your car. Easing off the gas is the best remedy if you want to "tighten" the turn. Braking - if you can - will probably slow you down more than you need to, and if the road is slippery or icy, you may end up losing control and stop "in the weeds".

In an oversteering situation, the rear end of your is losing traction and wants to move to the outside of the turn - which makes the front end turn in more sharply. Counter-steering can be very effective as long as you don't over-correct and end up "fishtailing". Braking will shift more weight to the front end, causing the rear wheels to have even less traction and possibly send you into a sideways skid - not fun if there are any other cars, pedestrians or buildings around. Again, easing off the gas is the best place to start to regain control of the vehicle.

Of course, our autocrossing friends are able to make good use of both of these phenomena...

 

playing gran turismo 3 for the PS2 would help anyone understand.. in addition to the game's great physics, theres a section in the manual that is kind of a crash course in racing from skip barber.

 

In the understeer solution, it would seem that if you corrected the understeer, either with breaking or turning more into the direction you want to go, when the tires regained traction in the front wouldn't you be almost immediately be thrown into an oversteer situation? I know with all the RWD cars I'ved had, when you corrected for the oversteer, you could find yourself straighting up in a nasty quick way, sometimes enough to find yourself in an oversteer situation in the opposite direction! It was always a careful balance of power (I never got out of the throttle, maybe ease off a bit) and wheel input. I drove the same roads to and from work for 11 years and there was an onramp to the interstate that had a little hump in the road and then a nice curve to the left. I could power slide my 3rd gen V8 Camaro right thru that baby....lots of fun, but like the statement made before.....oversteer=scared passenger. I always was in full control because I know the road and car so well.(still love the 3rd gen F Bodys....low and wide) But with the Maxima I'd be scared to death to try that same move!

 

In a nutshell, this is how you correct for oversteer in a Maxima. Video

Yes, a Maxima can get away from you in a hurry, there's not much gradual about it. As long as you don't panic and snap off the throttle, you should be okay.