Technical explanation of FF spinouts needed

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There are two cases of FF cars oversteered and spun out without any e-brake in which I couldn't find the exact cause for them.

1) Honda Accord 1999 4dr(my car). During a practice run I made a left C-turn too fast (60mph on a 35) and it was believed that the car understeered at first, to a point where the right rear wheel made contact with a pile of sandrock on the right side of the road, causing it to oversteer and spun 90 degrees counterclockwise. Steel wheels.

2) Late model Toyota Camry 4dr (some lady's car). Rainy road. Car seemed to turn at 50mph on a 45mph right C-curve but oversteered and spun out 270 degrees clockwise for no reason. My car can go 60mph in this condition. Looks like stock car with steel wheels as well. First assumption would be B traction tires on the rear wheels or racing tires on front, but that seems unlikely.

Also, in both cases the cars follow the curves as they spin out, leaving them undamaged and had made no contact with the wall.

Anyone care to tackle these two scenarios in a more complex sense?
 
Originally posted by 19xx
1) Honda Accord 1999 4dr(my car). During a practice run I made a left C-turn too fast (60mph on a 35) and it was believed that the car understeered at first, to a point where the right rear wheel made contact with a pile of sandrock on the right side of the road, causing it to oversteer and spun 90 degrees counterclockwise. Steel wheels.

Any situation where a car oversteers is caused by the amount of grip being exceed on one or both rear tires, plain and simple.

I wager two factors caused your little "moment". 1) Hitting the sand rock with the RR tire caused that tire to loose traction and since the outside tires do most of the work in a turn, the tire that was holding up your rear suddenly checked out. 2) When the car began to plow, you hit the brakes, didn't you? This was the "correct" thing to do to get out of the understeering situation, but in some extreme cases can put an FF car in a "trail braking oversteer" state. FF autocrossers actually encourage this behavior, because it lets them make more radical, tight turns.

Basically, you took traction away from the RR tire with the debris contact, then probably made it worse by taking the weight off the rear tires by hitting the brakes (causing weight to transfer forward). If you didn't hit the brakes when the car started to push, then it was just the debris.

What the hell were you practicing? Driving into a ditch?


Originally posted by 19xx
2) Late model Toyota Camry 4dr (some lady's car). Rainy road. Car seemed to turn at 50mph on a 45mph right C-curve but oversteered and spun out 270 degrees clockwise for no reason. My car can go 60mph in this condition. Looks like stock car with steel wheels as well. First assumption would be B traction tires on the rear wheels or racing tires on front, but that seems unlikely.

Also, in both cases the cars follow the curves as they spin out, leaving them undamaged and had made no contact with the wall.

Anyone care to tackle these two scenarios in a more complex sense?

Um. Rain can do funny things to a car's handling. This scenario could have been caused by a number of things. She could have hit standing water or a bump or both; her rear tires many have been worn slap-out or her air pressure was too low; the car's alignment may have been off, etc.. Standing water is the most likely culprit.

Either way, it seems both of you were driving too fast for conditions. Too much speed, too little skill and sense.


///M-Spec
 
Thanks MSpec. I couldn't exactly recall what happened, as it was over a year ago when I was doing some stupid ****. I was praticing the basis of traction limits when I realized I went too fast on that corner. I didn't put on the brakes until it hit the debris, which explains the spinout. IRight now I'm practicing trail braking along with left foot braking, but they're hard to master without going to dirt.

As for the second case, it was a curve that I crossed a million times, the gutters aren't dipped, smooth road, no standing water. This could only mean her tires, but why wouldn't it be the front wheels first? This happened two weeks ago, and I was just bringing up the first case because they're both speed and traction related.
 
Originally posted by 19xx
Thanks MSpec. I couldn't exactly recall what happened, as it was over a year ago when I was doing some stupid ****. I was praticing the basis of traction limits when I realized I went too fast on that corner. I didn't put on the brakes until it hit the debris, which explains the spinout. IRight now I'm practicing trail braking along with left foot braking, but they're hard to master without going to dirt.

You're welcome. Now, can you do me a favor? Pay $20 and attend an autocross novice driver's school and have someone teach you trail and left foot braking. You're much less likely to end up around a tree that way and its a hell of a lot more fun.


Originally posted by 19xx
As for the second case, it was a curve that I crossed a million times, the gutters aren't dipped, smooth road, no standing water. This could only mean her tires, but why wouldn't it be the front wheels first? This happened two weeks ago, and I was just bringing up the first case because they're both speed and traction related.

Like I said; rain will tend to exaggerate handling tendencies of cars. Without being in the driver's seat of that car, you really don't know what happened for sure. Did she hit the brakes in that turn too?


///M-Spec
 
The other thing to remember is that in an oversteer condition, 1) it will spin unless corrected or enough velocity is lost to regain traction, and 2) spinning cars go off the inside of the turn, not the outside, which means they tend to follow around the turn.
 
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