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Old 03-16-2004, 08:57 PM   #1
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Default Definition of understeer and oversteer

I see the terms understeer and oversteer used a lot. but exactly what are they exactly?

I assume it has something to do with when I take a turn to fast, whether it is the front end or the back end that breaks loose first.

I have tried to watch carefully, what happens when I try to take the hairpin turn at the end of the long straight away to fast. All I can see is the car going wide, I am not sure what breaks free first.

What is it I should be looking for to determine if car is understeering or oversteering.

--------------------
What confuses me also is talk about on power and off power steering and weight transfer/traction.

It seems to me, that the turns which are difficult to negotiate are the ones you have to decelerate for. (end of long or short staightaways) In this case the deceleration throws the weight forward on to the front wheels and these turns would all be off-power turns?

The turns where you are accelerating, trying to regain your lost speed, seem much easier to negotiate.
I am not sure if this is just the result of reduced speed or the front drive wheels pulling you through the corner.
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Old 03-16-2004, 09:05 PM   #2
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Oversteer is when the rear end is loose, which makes it spin out easier. Understeer is what you are describing. Going into a turn and turning the wheels and the car pushes out the corner.

Picture a circle.

If the car could go around the circle on the line we will consider that "neutral".

If it cannot hold the line and makes the circle bigger...UNDERSTEER

If it can go tighter and make the circle smaller at the same rate of speed as the neutral line then it has oversteer.
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Old 03-16-2004, 09:09 PM   #3
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Default Definition of understeer and oversteer

imjonah;

Simply stated:

Understeer is a LACK of steering in a corner. The Car wants to go straight (wide) instead of following the curve.

Oversteer is having an EXCESS amount of steering and the Rear end of the Car will feel loose.

Either problem can be caused by poor Car set-up or track conditions. The trick is to find that perfect balance that works with your Car and driving style on that particular track and day. (sometimes not so easy)
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Old 03-16-2004, 09:10 PM   #4
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Understeer: when the driver is scared.

Oversteer: when the passenger is scared.
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Old 03-16-2004, 09:12 PM   #5
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Quote:
Originally posted by psbarger
Understeer: when the driver is scared.

Oversteer: when the passenger is scared.
Haha, that is the truth. Amen!
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Old 03-16-2004, 09:12 PM   #6
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I think the best way to desrcibe it is in terms of traction. When the rear has too much traction, the car will understeer, or push. When the front has too much traction, the car will oversteer.
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Old 03-16-2004, 09:36 PM   #7
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I think Junior Johnson covered this one best:

Understeer is when you hit the outside wall head first
Oversteer is when you hit the outside wall tail first.
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Old 03-16-2004, 09:39 PM   #8
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Understeer or Push -

When the front end of the car hits the wall.

Oversteer or Loose -

When the back end of the car hits the wall.
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Old 03-16-2004, 10:26 PM   #9
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even simpler-
Understeer- Dont turn enough
Oversteer- Turning too much
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Old 03-18-2004, 12:42 PM   #10
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Default speed and understear/overstear

In other words understeer and oversteer is what happens when you try to make a turn with to much speed.

There is a limit to adjusting the car. There is a speed at which no matter how the car is setup or how you turn the wheel the car is going to brake loose and hit the wall. Correct?

For me and a lot of novice drivers the difficulty is not the line or the car setup, necessarilly; it is laying off the throttle just enough to not spin out, but not to much so we lose all our speed.

After 3 months I find that I am doing ok and improving on the curvey parts of the track, where the car is going relatively slow or accelerating.
It is the turns at the ends of straightaways where either I lose control because of excessive speed or I negotiate the corner to slow and lose speed and time.

The difficult part for me is letting off the power at the right time and for the right amount. 1/4 second to late and the car is another 3 feet closer to the corner, since there is no speedometer and the slightest movement of the throttle gives pretty significant differences in speed; it is very hard to move your throttle finger the same amount from lap to lap.

I am getting a little better at the throttle control each week, it just seems like there is a giant gap in my ability to get the corner speed right and the experienced drivers.
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Old 03-18-2004, 02:27 PM   #11
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You're kind of thinking the right way. But you can have an off power push, meaning on the slower corners the car is not transfering the weight forward enough to get the front end to grip. You can also have too much on power steering. The key I found when you're learning to drive is to get a good soilid, easy to drive setup and learn throttle control. An easy to drive car is pretty neutral. It's not always the fastest though. But when you're learning to drive, it will help you to handle the car better.
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