As you know from reading Oversteer, Understeer, and 4 Wheel Drift, Oversteer is what happens when your rear tires lose traction before the front tires while the car is turning. This causes the car to begin to spin and, if not corrected, the car will spin out completely.
Power Oversteer
When most people think of Oversteer, they think of a very powerful rear-wheel drive vehicles spinning the rear tires by the sheer power of the engine. This is known as Power Oversteer. This is a typical (and amusing) means to induce Oversteer, but it is only one way to get your car sideways.
Weight Shift and Traction Imbalance
The key to oversteer is an imbalance of traction between the front and rear wheels. When a car’s rear tires lose traction in a corner before the front tires, Oversteer will always result. Why the rear tires have lost traction is irrelevant - all they (and you) care about is that they no longer have the necessary grip to keep the car in line. In the example above of Power Oversteer, the rear tires have lost traction before the front tires because their available grip has been used up by acceleration force. By turning and trying to accelerate, you ask too much of the tires and they begin to slip.
The other way to induce Oversteer is through a weight transfer. When you turn, the weight of the car is shifted to the outside wheels. When you accelerate, the weight of the car shifts to the rear wheels. And when you brake, the weight of the car shifts to the front wheels. Tires gain grip when they have more force (e.g. weight) applied on them, and lose grip when they lose this force. When you brake, you transfer a tremendous amount of weight forward onto the front wheels. This makes the rear of the car very light, and the rear wheels consequently lose a lot of traction. The front tires, however, have now gained a significant amount of traction because of all the weight that has shifted forward (all of the traction that the rear tires lost, to be precise). This means that if you are turning after a forward weight shift, you’re front tires may have far more traction than your rear tires, and your car may begin to oversteer.
Lift Throttle Oversteer
One example of such a weight transfer is Lift Throttle Oversteer. Say you are going through a corner at neutral throttle at maximum cornering grip. Both your front and rear tires have equal traction, and the car is turning just fine. Now imagine that you suddenly lift off of the throttle completely. You have now removed the accelerating force pushing back on the rear tires, as well as caused the engine to start engine braking. Both of these phenomenon cause the weight of the car to shift forward dramatically. Now your front tires have a lot of traction, but your rear tires have lost a lot of traction. Since your rear tires were already at the limit of traction previously, they now no longer have the grip necessary to keep the car turning and your car will spin.
Brake Oversteer
Brake Oversteer works on exactly the same principles as Lift Throttle Oversteer, only the input is from the brake pedal, rather than the throttle. Say you are cornering aggressively and decide to slam on the brake pedal. Doing so transfers the weight of the car forward on to the front wheels, giving them traction, and off of the rear wheels, robbing them of traction. You now have an imbalance of grip between the front and rear tires. If the rear tires lose too much traction, they will no longer be able to keep the car turning and your car will spin.
Correcting Lift Throttle and Brake Oversteer
The techniques for correcting Lift Throttle and Brake Oversteer are identical. Both situations are the result of an improper weight transfer, so both must be corrected by transferring the weight back where it is needed.
The first thing to do in any Oversteer is to countersteer. This term should be familiar to you from Oversteer, Understeer, and 4 wheel drift [link]. If you don’t counter steer, any other actions will be useless.
The next step is to transfer the weight of the car back to the rear wheels. The best way to do this is with the throttle. Remember, when you are accelerating, the weight of the car shifts to the rear wheels. Though it may seem like an odd concept, this holds true even when the car is doing more erratic maneuvers like sliding sideways through a corner towards that wall you REALLY don’t want to hit. When tires slip, they have lost some traction that they would otherwise have if they were not slipping, but they have not lost all traction completely. Therefore, you can still apply forces through those wheels while they are slipping.
So, to transfer weight back to the rear wheels, you should give the car some throttle. The key word here is SOME throttle. As outlined above, too much gas will put you into Power Oversteer. Then you will have entered a downward spiral that will end in that wall you didn’t want to hit. This is a bad thing, so don’t give car too much gas. Instead, give it a little bit of gas. You want just enough gas to shift some of the weight back to the rear wheels to help them regain traction.
How much gas is a little bit of gas? This depends entirely on your car, your engine, your tires, and your car’s throttle response. Less powerful cars can get away with more gas in this situation, as it is harder to induce power oversteer (make no mistake, though, even the crappiest rear-wheel drive car will easily be able to induce power oversteer in this situation). For my Miata, I like to think in terms of pressure on the throttle, rather than any given throttle position. When I need to shift power rearward, and increase my pressure on the pedal. This moves the pedal just a little bit, but just enough. Your car may be different, so your best bet is to practice in an open space off of the road and away from any other cars or objects.
on April 2, 2007 at 12:25 am The Pansy Patrol - Info for the 3000GT / Stealth Community wrote:
[...] Our Most Useful Entries « Indepth Oversteer: Different typ… [...]
on April 2, 2007 at 2:43 am savers tips » Indepth Oversteer: Different types and how to correct them wrote:
[...] unknown wrote an interesting post today onHere’s a quick excerptAs outlined above, too much gas will put you into Power Oversteer. Then you will have entered a downward spiral that will end in that wall you didn’t want to hit. This is a bad thing, so don’t give car too much gas. … [...]
on September 24, 2007 at 11:41 am The Pansy Patrol - Info for the 3000GT / Stealth Community wrote:
[...] while cornering is a combination of brake oversteer and throttle oversteer, which we covered in Indepth Oversteer: Different types of oversteer and how to correct them. The basic principle at work is weight transfer. When you lift off of the throttle, weight [...]
on October 8, 2007 at 10:05 pm The Pansy Patrol » Threshold Braking wrote:
[...] you will recall from Indepth Oversteer, tires have more grip when they have more weight on them. When you brake, the car’s weight [...]
on August 16, 2008 at 12:28 pm The Pansy Patrol » The Dangers of Committing to a Corner wrote:
[...] corner itself. The issue is that when you push the envelope enough, you risk spinning from either lift-throttle oversteer or brake oversteer. The threshold for either brake or lift-throttle oversteer is MUCH lower than the [...]
on August 22, 2008 at 8:44 pm Shingo41 wrote:
can’t lift-throttle be harnessed if performed correctly? I have heard a lot of people talk about it as though it is a bad habit, but I use it a lot in my FWDriver to make minor corrections for corners. Albeit, nowhere near to the car’s limit.
on August 25, 2008 at 11:05 am Noah wrote:
That is a really good question, Shingo (and one I should probably address in its own article at some point). You are 100% correct in the technique/application you are talking about, but I would hesitate to call it lift-throttle or lift-throttle oversteer. To me, what you describe is sounds more like throttle-steer, whereas lift-throttle brings up connotations of the rear end coming around. That is getting a bit into semantics, so no big deal on what you call it.
As far as application goes, you are correct in that it is an indispensable tool. Major steering inputs are obviously done with the steering wheel, but any fine-tuning is all done with the throttle. In that sense, it is not only not a bad habit, but an integral part of smooth, high performance driving. That said, make LITTLE inputs with the throttle. Too sudden of a lift will take you into lift-throttle oversteer very fast, and then you’re in trouble.
on September 10, 2008 at 6:59 pm shingo41 wrote:
Thanks for the clarification. I Learn something new every day.
on March 28, 2010 at 6:03 am Astraist wrote:
An overly simplistic explaination, originating from a lack of knowledge to understand a skidding car. The skid occurs in two stages:
First, the skid itself, which is the balance matters you described, resulting in one, two or three wheels losing adhesion and one axle becoming “loose”. This occurs down the straight and is felt through the seat and steering, rather than seen. It is a result of weight transfers and bad utilization of tractive force or, in other words, a bad synchornization between the hands and feet, with the strees being on the pedals and not the steering.
The second stage occurs when the driver turns the wheel into a corner/lane, which (due to the imbalance) results in an unexpected response from the car (the car too much or too little of what the driver asks it to do), resulting in the car not following the intended line.
Where many drivers (on the track or otherwise) go wrong is not to pay attention to the first stage by not paying attention to feedback from the car. They view the skid as a mere change in the direction of the car and correct it simply by pointing the steering wheel back towards the right direction.
The problem is, that the slide happened eariler. Therefore, the corrective input applied by the driver will be performed later into the skid, and will be wrong and normally only increase the force acting on the car or simply not being efficient.
The correct solution is to the feel the slide early in the first stage and than correct it by removing the cause of the slide and decreasing the cornering demands, and only than making further adjustments to the direction of travel. This means using the pedals to do just the opposite of what got you into the slide, while straightening out the steering, and only than steer where you want to go.
In the particular event of lift-off/braking oversteer, this means feeling the slide according to the sensation of the loose back-end and tight steering, rather than leave it to the point where the car attempts a spin. Additionally, getting back on the power to shift weight backwards and remove the cause of the slide, is far more important than countersteering and will come eariler!
The only thing that can readhense the rear wheels in the throttle. By not getting on it, we multiply our steering input by zero! This means one of the following:
1. You spin even though you input full opposite lock.
2. You spin even more harshly the other way.
3. If your speed is not high (which is almost never the case on the track) and your steering correction is quick, your steering input counteracts the slip-angles of the rear-tires, but still cannot remove the cause of the slide. The result is for the driver to countersteer untill he runs out of lock, and than wait for the car to lose speed and hope you do not run out of road before you run out of speed.
If you steer before getting back on the power, you might exceed the point of no return and spin or cause the car to suddenly re-grip as you get on the power, with the wheel sharply turned the other way, resulting in a violent slide the other way.
Therefore, the correct recovery involves getting back on the power while taking some of the lock off, and only than countersteer as nessecary. How much power (and therefore how much steering) depands on many factors: Road incline, corner severity, speed, traction, cause of the slide, drivetrain, degree of sliding.
One example: Say I found myself completly sideways after being ticked. I need to get the weight back to the rear of the car, but I also need to steer the car back on the right direction. Therefore, I need to keep constanst throttle to get the rear to grip, while still keeping the front gripping to get the car turned back on the right line.
Now, say my car is a WRC rally car and that the speed in relatively low. In this case, I can keep full throttle, because the central differential is going to detect the situation and transfer all of the power to the front. Since the car is light, the engine is strong, and grip is not maximized, this would result in the front wheels spinning and sliding back towards the right line.
A third example, say my rear tires blew up, or that I’m driving on ice/skimming on water (aquaplaning). In this case, there is little advantage to be gained from weight shifts and therefore you press down on the clutch to regain natural tire rolling action. See, it’s far more complex than it appears.
If we expand the disscussion even more, we see that there are other causes of sliding:
1. Power oversteer: The driver has to do the exact same thing, just reduce the power application rather than increase it. The power is still more important than the steering, though!
2. Roll-oversteer: The driver keeps constant power and corrects with steering.
on April 4, 2010 at 11:11 pm Noah wrote:
Incorrect for a variety of reasons.
First, your assertion that the only way for the rear tires to regain traction is via application of the throttle is flat out wrong. I have been in numerous cars, in numerous spins, with numerous people in the driver’s seat, and in many of those spins which were recovered, the only correction done was to turn into the spin. Indeed, sometimes the driver even lifted COMPLETELY off the throttle, yet still recovered. You are correct that a slight application of the throttle will oftentimes shift weight back to the rear wheels and thus help them regain grip. But your conclusion that failure to do always will result in the rear continuing to slide is wrong.
Second, your assertion about “removing lock”. I’m not really sure what you mean by “the correct recovery involves getting back on the power while taking some of the lock off, and only than countersteer as nessecary (sic).” This could be interpreted as 1) counter steering and then steering away from the spin, or 2) just steering away from the spin. Fortunately we need not flesh out which interpretation you intended because both are wrong. It is an axiom of performance driving that you turn into a spin. Yes, there may be some circumstance or instance somewhere, sometime, when actively turning away from the spin nonetheless leads to recovery, but I have yet to see or hear of such an occurrence. Further, even if there was such a situation, that does not mean that turning away from a spin would be be a viable technique as applied generally.
Third, your complaints about the timing of recovery techniques. As noted above, you assert that only throttle application will lead to regained rear wheel traction. And as noted above, that assertion is false. Your timing sequence, however, is based upon this false premise - that only throttle application will allow the rear wheels to regain grip. As I note above, in my experience the one technique that is most likely to save you in a spin is to countersteer, hence my positioning it as your first action. Mind you there nothing precluding you from BOTH countersteering and applying slight throttle simultaneously, and indeed that is generally the best technique. But if you are to think in terms of concrete, discrete steps, then I still conclude that countersteering should be done FIRST as it is most effective.
Finally, your assertion that there are two phases of a spin: 1) the failure to not prevent a spin flowing back to your actions on the straight, and 2) the actual spin. This analysis is wrong because you assert that every spin inherently must have both of these phases. This is incorrect. Not every single spin can accurately be predicted from the straight. For example, if you are following a car that suddenly dumps some slippery fluid right in front of you, you may well begin to spin. And precisely because this situation was completely non-existant and non-predictable while on the straight, none of your actions or inactions on the straight have any bearing whatsoever to the spin and the recovery thereof.
You are correct in that many/most spins can be traced back to a poor corner setup. Indeed the biggest indicator of driving skill to me is how early a driver is able to recognize ANY problematic situation, be it a possible spin, early apex, etc. But as I note above, this analysis is not applicable to every spin, and thus it cannot be a distinct “phase” of a spin. Really, it isn’t a “phase” at all, but simply the situation that led up to the actual spin itself. In terms of actively preventing a spin from happening, or anticipating and mitigating the severity of the spin, obviously measures can be taken before the actual spin. But this analysis and the inputs required is distinctly different from what should be done when you have actually begun to spin.
on April 9, 2010 at 4:20 pm Astraist wrote:
Before I start, I want to clear up something which might have caused confusion: I did not mean oversteer is corrected by the throttle, but that the correction mainl depends on the throttle rather than steering. The weight transfer/reduction of longitudal tractive force is more important than the steering corrections.
The two phases of the slide are not nessecarily apart on the time scale, and neither is the correction. The difference goes much deeper. The bottom line is that the first and most important thing to do is to remove the cause of the slide and any corrections to the direction of travel are at most secondary.
Furthermore, if you correct early enough with the power, you hardly need to correct the trajectory of your car, I.E. You do not need to countersteer. In FWD cars and many AWD cars, countersteering means correcting too late or too much. Many rear-wheel drive cars can also be handled without countersteering, it’s slowing you down.
Let’s think: We shift weight forward by braking. The rear is rendered light. What do we do to get it to grip? Shift the weight back to the rear. If we countersteer, how exactly do we do that?
Yes, if speeds are not too high, lifting off of the brakes can often resolve the slide. Additionally, it is possible for the steering angle of the front to compensate for the slip angles of the rear, but this is only enough to balance the slide, not terminate it. What you are basically doing is to wait for the car to lose speed, eventually regaining grip.
What you have experienced in cars is probably one of the two cases above. For something to work in several occasions does not qualify it to be a proper technique. In every high-class racing school, rallying school or skidpan in Europe that I know of, the consensus leans to my explaination rather than yours.
In several demonstrations I attended at the driving schools of Drive-Art in Israel, On Yaakobson (Competetor at Formula Mazda), Danny G (competetor at Formula Vauxhaul) and Lior Levi (Competetor at JMC racing) they showed lift-off oversteer and it’s correction:
Attempt one: Car makes a full 180 degrees spin in spite of an instant application of full opposite lock.
Attempt two: Driver countersteers and also tries to get on the gas. When he gets on the power, weight shifts backwards and the car immediatly stops sliding but the wheel is turned against the slide, so the car spins the other way.
Attempt three: The instructor gets on the gas to stop the slide and straightens the steering witout countersteering and the car straightens up.
So yes, they could have made it in other ways, but the correct technique is the one applied in the third attempt.
Oh, and it’s interseting how when Jason Plato (WTCC) was knocked completly sideways in a FWD Chevrolet, the pulled it back straight and later than “The first and most important thing you do is to get hard on the gas”!