What causes snap-oversteer?

[MIE1992]

I understand that it's mostly an issue for MR cars, and that it's caused by lifting of the accelerator as you go into a turn. But that's pretty much all I understand. Like, what causes it, on a mechanical level? What can I do, in regards to the control of the throttle/brake to avoid it? Is it exclusively an MR car issue, or can it occur with FR cars, too?

 

[coryclifford]

And FWD cars. Weight transfer.

 

[Lebowski]

I own 2 rwd cars; an E92 M3 and a track prepared RX8. Both have snap-oversteer, especially the RX8. I put it purely down to a mis timing of weight transfer against the current speed when lifting off. I dont think anything as an average driver can be done to conquer it whether in real life or in a game. The fact we get it in GTS just demonstrates how acurate the games physics are.

 

[GT5 Level 41]

Tire tread compound and tread depth also contribute to that. Driving on mismatched tires is always exciting with pushing the limits.

 

[DriftMethod]

In a nutshell... While turning, if you lift off the accelerator, weight is transferred off the rear tires and onto the front tires. This increases grip at the front and decreases grip at the rear. If you were using close to the full grip at the rear before you lift off the accelerator, the rear tires will then slide due to the sudden decrease in available grip caused by weight transferring to the front.

MR are more susceptible to this because most of the weight is near the center of the car. This makes it quicker to rotate around the center point when front/rear grip levels change.

 

[TonyJZX]

This is a recent example? Also exacerbated by surface undulations.

This livery is also available you know where!

 

[ARTAsean]

In a nutshell... While turning, if you lift off the accelerator, weight is transferred off the rear tires and onto the front tires. This increases grip at the front and decreases grip at the rear. If you were using close to the full grip at the rear before you lift off the accelerator, the rear tires will then slide due to the sudden decrease in available grip caused by weight transferring to the front.

MR are more susceptible to this because most of the weight is near the center of the car. This makes it quicker to rotate around the center point when front/rear grip levels change.

This is called lift off oversteer, which is different from snap oversteer.

 

[DriftMethod]

This is called lift off oversteer, which is different from snap oversteer.

I've always heard of them being interchangeable terms for the same thing. Please explain the difference.

 

[ARTAsean]

I've always heard of them being interchangeable terms for the same thing. Please explain the difference.

The snap of oversteer that occurs when the rear tires regain grip before a wheel is straightened out



What happens in this video at :30

 

[DriftMethod]

That looked more like an out of control pendulum turn (aka Scandinavian flick.) Very similar in principle, but generally not considered snap oversteer from what I've heard.

 

[Chevy Heavy]

What can I do, in regards to the control of the throttle/brake to avoid it?

Practice, practice, practice. But seriously, the problem you're describing may be directly related to this non-linear-throttle . Basically what is happening here is throttle is being applied on a curve instead of a straight line. So while you think you're only giving a little gas through the pedal, the game is actually applying more throttle causing the wheels to break loose. This is a very annoying problem that many would like to see fixed.

 

[Imari]

I understand that it's mostly an issue for MR cars, and that it's caused by lifting of the accelerator as you go into a turn. But that's pretty much all I understand. Like, what causes it, on a mechanical level? What can I do, in regards to the control of the throttle/brake to avoid it? Is it exclusively an MR car issue, or can it occur with FR cars, too?

Can happen to any car, it's just that MR cars tend to lose it faster. Fundamentally it's about weight transfer, as others have said. What you can do is be smooth on your controls. This means all the controls, accelerator, brake and steering. It also means that you have to be smooth on AND off of them.

A common mistake that people don't think about is coming off the brake too quickly. This can upset the car just as much as jumping on the brakes too fast, and it's often worse because you come off the brakes just as you're turning in. A few extra tenths to feed out the brake can help a lot.

As far as MR cars specifically, you can get a lot of stability out of proper throttle management. They tend to be very sensitive to weight on the rear tyres, and so often adding throttle can stop you from oversteering, even in situations where you might not expect it. At the same time, too much throttle will light up the rear tyres and guarantee oversteer so it really is a learned skill.

I recommend going to a simple track, starting slow and building up your speed. This isn't to get faster or practice your skills, this is so that you can identify when, where and why the oversteer occurs. Then you can look at how you can change your driving style to avoid or remove those situations.

Have a look at this video. The whole thing is good, but this section at 15 min on the skid pan may explain more of what you want.

 

[Haitauer]

At the same time, too much throttle will light up the rear tyres and guarantee oversteer so it really is a learned skill.

In some situations I have found short shifting to be the best way preventing this. Especially in race situations where consistency is more important that last tenths in lap time.

 

[TonyJZX]

"Lift off" as the name suggests, what happens when you 'lift off' the throttle... you're unloading the axle so theres sudden weight transfer that upsets the car... its a counter intuitive thing because in most cases you get off the power if you think that theres something wrong but in this case, it makes it worse.

 

[Venster]

I find the predominant reason for lift off oversteer in this game is changing down the gears too quick hence transferring the weight to quickly.

Take an MR car out at Yamagiwa, around the first fast left hander. Usually in fifth gear by that point as you brake and turn in and change down to fourth the back will break loose. Do the same but from sixth to fifth and it will remain stable.

I find MR cars can suffer on tracks such as Yamagiwa, Maggiore and first corner of Interlagos. You need to be more delicate with how you decelerate into some corners.

 

[TonyJZX]

I find the predominant reason for lift off oversteer in this game is changing down the gears too quick hence transferring the weight to quickly.

There's a few types of that kind of thing.

Like in real life if I'm slowing down for a corner and I go 3rd to 2nd too fast and rely on engine braking and not the actual brakes to slow down, I can get the car to shimmy its back end... the car keeps going straight but you can feel the car wagging its tail.

This is an RWD car. I dont think its actually 'oversteer'. I cant think of the term for it right now.

I also think a lot of the symptoms described in the thread are nullified by your electronic stability control. I suspect much less so in the game.

 

[eran0004]

I find the predominant reason for lift off oversteer in this game is changing down the gears too quick hence transferring the weight to quickly.

Don’t forget that the gears act as a torque multiplier, so the lower the gear, the more engine braking torque you get on the drive wheels. For a rear wheel drive car it can be almost like pulling the hand brake if you shift down too soon.

 

[TonyJZX]

It came to me. Its called 'compression braking'.

Good idea not to do it as it places stress on the driveline when you should be just stressing your pads.

 

[cleanLX]

The original question is regarding snap oversteer... not lift(trailing throttle) oversteer, not Scandinavian flick... not throttle induced oversteer.
Snap oversteer is when the car is already in a slide, then it "snaps" to the opposite direction.
This is due to the rear wheels gaining traction while the fronts are still steering into the skid.
In the Skip Barber video above this is illustrated at the 20:40 moment, but, he did not explain what happened, other than the fact that he noted he had not recovered. In the previous examples (same video) the driver rolled steering back as the rear gained traction, catching the slide, at 20:40 he was too slow rolling steering out, the rear gained traction while the fronts were still steering into the skid, and it snapped around on him. (I'm sure he did this on purpose, and maybe later in the video he addressed/explained it...)
In real life, this will often happen when a car goes into a skid, and the driver lifts off the throttle while steering into the skid to catch ... but having lifted off, the rears gain traction, the driver cannot react fast enough with steering inputs, and... snap.
In real life you will rarely see a driver lift once a skid is in place... the age old "when in doubt throttle out"... You want to control the skid with throttle and steering, to bring all events back into order... lifting off throttle now places the rears on a path of regaining traction on their own, and now you are down to reacting once that event occurs... with throttle, you are controlling when the tires regain traction and have calculated the steering inputs... aka you are in control of the slide.

So, the Scandinavian flick... yes, it is a means to induce snap oversteer... to get the car sliding prior entering the corner. You typically only see the Scandinavian flick on gravel/snow events... or for hooligan purposes. The reason it's used in gravel/snow is because a car is quicker through a corner while in a controlled slide than it is neat/tidy and hooked up. The reason for this is because while sliding you are pushing gravel/snow, which is causing friction, aka grip... same reason a car will stop faster on gravel/snow locked up than it will with ABS... again, with the wheels locked you are piling up gravel/snow(certain types, with decent footing underneath) in front of the tires, adding friction, stopping quicker... ABS is safer in that you will still be able to steer, but it will not stop you faster in these circumstances.

 

[Imari]

The original question is regarding snap oversteer... not lift(trailing throttle) oversteer, not Scandinavian flick... not throttle induced oversteer.
Snap oversteer is when the car is already in a slide, then it "snaps" to the opposite direction.
This is due to the rear wheels gaining traction while the fronts are still steering into the skid.

That's a commonly used definition, but reading the rest of the OP's post I doubt that's the question he's asking.

Lift-off oversteer (also known as snap-oversteer, trailing-throttle oversteer, throttle off oversteer, or lift-throttle oversteer) is a form of oversteer in automobiles that occurs while cornering when closing the throttle causes a deceleration, causing the vertical load on the tires to shift from the rear to the front, in a process called weight transfer. This decrease in vertical load on the rear tires causes a decrease in the lateral force they generate, so that their lateral acceleration (into the corner) is also decreased. This causes the vehicle to steer more tightly into the turn, hence oversteering. In other words, easing off the accelerator can cause the rear tires to lose traction, with the potential for the car to leave the road tail first.

https://en.wikipedia.org/wiki/Lift-off_oversteer

Snap oversteer can also be used to describe lift-off oversteer, especially aggressive lift-off oversteer as it can feel like the car just "snaps" and spins off into the weeds.

 

[sundaydriving]

I got it once in the NSX GR2 yesterday on brands out of the last corner - full throttle, must've lost traction briefly? I think i audibly said WTF. Only happened once. snapped and boom, lap over.

 

[DriftMethod]

The original question is regarding snap oversteer... not lift(trailing throttle) oversteer, not Scandinavian flick... not throttle induced oversteer.
Snap oversteer is when the car is already in a slide, then it "snaps" to the opposite direction.
This is due to the rear wheels gaining traction while the fronts are still steering into the skid.
In the Skip Barber video above this is illustrated at the 20:40 moment, but, he did not explain what happened, other than the fact that he noted he had not recovered. In the previous examples (same video) the driver rolled steering back as the rear gained traction, catching the slide, at 20:40 he was too slow rolling steering out, the rear gained traction while the fronts were still steering into the skid, and it snapped around on him. (I'm sure he did this on purpose, and maybe later in the video he addressed/explained it...)
In real life, this will often happen when a car goes into a skid, and the driver lifts off the throttle while steering into the skid to catch ... but having lifted off, the rears gain traction, the driver cannot react fast enough with steering inputs, and... snap.
In real life you will rarely see a driver lift once a skid is in place... the age old "when in doubt throttle out"... You want to control the skid with throttle and steering, to bring all events back into order... lifting off throttle now places the rears on a path of regaining traction on their own, and now you are down to reacting once that event occurs... with throttle, you are controlling when the tires regain traction and have calculated the steering inputs... aka you are in control of the slide.

So, the Scandinavian flick... yes, it is a means to induce snap oversteer... to get the car sliding prior entering the corner. You typically only see the Scandinavian flick on gravel/snow events... or for hooligan purposes. The reason it's used in gravel/snow is because a car is quicker through a corner while in a controlled slide than it is neat/tidy and hooked up. The reason for this is because while sliding you are pushing gravel/snow, which is causing friction, aka grip... same reason a car will stop faster on gravel/snow locked up than it will with ABS... again, with the wheels locked you are piling up gravel/snow(certain types, with decent footing underneath) in front of the tires, adding friction, stopping quicker... ABS is safer in that you will still be able to steer, but it will not stop you faster in these circumstances.

I disagree with your definition of Snap Oversteer. I did a search and have only found it as a synonym for Lift Off Oversteer. It really doesn't matter though, as long as we distinguish in other terms to avoid confusion.

Scandanavian Flick or Pendulum Turn is a technique used to avoid understeer by increasing yaw (rotation) at corner entry. Generally used in rallying, but the physics can also be felt on roads with linked turns requiring quick direction changes.

 

[outofspace]

It can be also caused due to understeer! Loosen the rear anti-roll bar helps in that case but that depends on the car or where it occurs(corner entry, apex or corner exit)

 

[manion]

OP are you talking about when you feel like you are easing the throttle on when exiting the corner and all of a sudden you are facing the wrong way? Ive found its the previously mentioned non-linear throttle that causes the back to snap around because it goes from 50% to 100% throttle very quickly in GTS

 

[Imari]

It can be also caused due to understeer! Loosen the rear anti-roll bar helps in that case but that depends on the car or where it occurs(corner entry, apex or corner exit)

That can be a tough one. Loosening the rear bar will help the rear grip better, but it also means that when it lets go it will go very quickly. Sometimes tightening the rear bar can be more effective, as counterintuitive as that sounds. You get less grip, but the rear will let go in a more predictable and progressive manner.

Unless you're an alien you'll often find yourself going faster with a car with more controllable and progressive characteristics but less overall grip. That's what I often find when I drive with alien tunes, they're super soft and grippy but I just don't have the skill to consistently ride that fine line like they do to be fast. I prefer to stiffen it up a bit, and that extra bit of controllable slip as a warning that I'm maybe pushing too hard lets me be a lot more confident and aggressive in my driving without putting the car into a wall.

 

[vxr58]

Be gentle with the car going in, through, and out of the corner. Being gentle may not actually be the quickest technique for any given corner but unless you know how to deal with the consequences of not being gentle, be gentle. Of course in the real world, just make sure you don’t turn off your ESC.

 

[DriftMethod]

A safer line can be used to avoid Lift Off Oversteer.

• Use less trail braking. Brake in a straight line and delay turn in.
• At turn in, use more steering input to get most of the rotation done in one motion.
• Use a later apex to straighten out the line from apex to exit.
• The straighter apex to exit line allows the throttle to be fed in earlier and when there's less steering angle. This should minimize both the probability that driver will need to lift off throttle and the severity of any oversteer if throttle is lifted.

Unfortunately, this line doesn't fit well on really long turns like at Yamagiwa.

 

[ScottPuss20]

I think the Super GT NSX is the snap oversteer king. The slightest touch of the throttle mid corner and you're off. It is an absolute pain to drive arse a result and you constantly think about all the variables mentioned above like throttle, braking, turning and weight transfer. That becomes highly overwhelming in a race when soo many things can go wrong.

 

[raghza]

I've always heard of them being interchangeable terms for the same thing. Please explain the difference.

Basically lift off oversteer will spin the car in the same direction as the corner and is caused by back to front weight transfer (like when coming off throttle during a turn).
Snap oversteer will spin the car in the opposite direction and is caused by sudden high grip levels while your front wheels are still countersteering the slide.

 

[outofspace]

That can be a tough one. Loosening the rear bar will help the rear grip better, but it also means that when it lets go it will go very quickly. Sometimes tightening the rear bar can be more effective, as counterintuitive as that sounds. You get less grip, but the rear will let go in a more predictable and progressive manner.

Unless you're an alien you'll often find yourself going faster with a car with more controllable and progressive characteristics but less overall grip. That's what I often find when I drive with alien tunes, they're super soft and grippy but I just don't have the skill to consistently ride that fine line like they do to be fast. I prefer to stiffen it up a bit, and that extra bit of controllable slip as a warning that I'm maybe pushing too hard lets me be a lot more confident and aggressive in my driving without putting the car into a wall.

That was exactly what i was doing, but as i got a little more experience using the steering wheel(cause it's my first one) i now find myself beeing able to loosen the rear bar, nor crazy but from 10 to 7 it's enough & counter it with the frequency, rebound & smoother driving!