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Anti-skidding lessons
(120 posts, started )
Quote from ans7812 :you never apply throttle if you're trying to save a skid...

you do if you want to control the gentle exit of a skid...
other than that - yes, release the gas = stop the skid
This thread was about saving skids on the road. Majority now is talking about how you do it on the track to be as fast as possible. In traffic you just want to stop as quickly as possible.
They taught me to just press the clutch, brake and come to a halt. Whereas you didn't need to brake, also, clutch, and when you saved the skid, come to a halt.
Quote from ans7812 :As you round the bend, the instructor says "LIFT!" (meaning lift off the throttle).

From what you were describing you were lifting before you started skidding and then the instructor pulled the handbrake? Well from a mechanical point of view you don't want to be applying power to the rear wheels and using the handbrake at the same time and by lifting you were creating lift off oversteer.
If you have power oversteer, the last thing you want to do is reduce the throttle! I can't think of many ways of getting you to the scene of the accident faster.

Applicable to both road and race driving (the physics are the same).
if you lift off completely, does'nt that like cause the wait to transfer, thus making you spin or something? If im wrong, forgive me. The only RWD car i have drove was an old 318i and an old sierra and i was only pottering them around a car park
Quote from Nathan_French_14 :if you lift off completely, does'nt that like cause the wait to transfer, thus making you spin or something? If im wrong, forgive me. The only RWD car i have drove was an old 318i and an old sierra and i was only pottering them around a car park

But if you're already skidding it doesn't make a difference! Thas what no one is understanding. I don't care if you think you know what you're talking about because you race in real life. If you're caught in the middle of a skid, and need to correct it, get your feet off everything and countersteer. Why the hell would you want to add power if you're sliding 90 degrees towards a parked car on the other side of the street?
Well i did'nt say i know everything because i race so i dont know where you got that from, but i was talking about FWD oversteer. Putting on power WILL help to correct the oversteer on a FWD car, providing you apply the right ammount of steering to go with it. Putting throttle on oversteer from a RWD car helps to, whenever im in my dads car (RWD cossy) and he gets the back end out, he always applys throttle whenever he wants to keep the slide going or if he wants to straighten it out. Applying throttle to RWD or FWD can help, depending on the circumstances.

Edit: I just thought, are you sure your not talking about understeer? Because when you get understeer, letting off the throttle abit or completely does help then.
Quote from Nathan_French_14 :Well i did'nt say i know everything because i race so i dont know where you got that from, but i was talking about FWD oversteer. Putting on power WILL help to correct the oversteer on a FWD car, providing you apply the right ammount of steering to go with it. Putting throttle on oversteer from a RWD car helps to, whenever im in my dads car (RWD cossy) and he gets the back end out, he always applys throttle whenever he wants to keep the slide going or if he wants to straighten it out. Applying throttle to RWD or FWD can help, depending on the circumstances.

Edit: I just thought, are you sure your not talking about understeer? Because when you get understeer, letting off the throttle abit or completely does help then.

Exactly...depending on the circumstance, if you're in an emergency why would you want to power on and total w/e it is that you were heading for?

and btw, that comment about racing in real life was not directed at you.

Also i should be more clear about what the instructor was doing. If the lift throttle over steer did NOT produce a slide, THEN he would pull the handbrake for a second.
Can we sort this.

If the car oversteers and it was caused by:

Too much throttle - then don't come off the throttle, it will make things worse.
Sudden closing of the throttle (nee Lift of Oversteer) then going to neutral throttle will probably help
Nothing to do with throttle (e.g. too much rear bias, handbrake application, being hit) - leave the throttle alone and correct the car.

If the car understeers and it was caused by:

Too much speed - lift off and hope that steering and engine braking will slow you down before you crash. Don't brake (but if you do, be VERY gentle)
Too much throttle - get out of the throttle, but don't lift completely - understeer to lift off oversteer isn't fun!
Very heavy front end, or braking whilst turning - using the throttle to reduce load on the front tyres might help them grip. Or the increased slip angle at the rear might balance the understeer and reduce the turning radius.

For all the above, and any more you might think of - there is no hard rule for any situation. It's about making judgement calls using as much experience and knowledge you have, combined with the feeling and instinct at a given moment.

All apply on the road or the track (though you are more likely to see them on the track unless you are a hoon!).
#35 - axus
I'd also like to throw a it of actual physics in:
Tyres, naturally, have the most available lateral grip per slip angle with 0 (or very close to) longitudinal slip. When you lift off the throttle completely, you are going to get negative longitudinal slip (the greater the speed, the more so).

Oversteer is caused by a relative lack of lateral grip at the back compared to the front. Lifting off completely in an RWD car will not only will you lose rear grip due to weight transfer but you will also not have neutral longitudinal acceleration. The most you should ever lift of in a slide is to the neutral throttle position - ie. the position that will keep your speed constant. In a FWD car, adding throttle (enough so to accelerate, ie. pulling out of the slide with power) will decrease the relative grip at the front by increasing the longitudinal slip and thus decreasing the front tyres' lateral grip and by transferring weight to the rear of the car.
Quote from ans7812 :But if you're already skidding it doesn't make a difference! Thas what no one is understanding. I don't care if you think you know what you're talking about because you race in real life. If you're caught in the middle of a skid, and need to correct it, get your feet off everything and countersteer. Why the hell would you want to add power if you're sliding 90 degrees towards a parked car on the other side of the street?

Your still talking as though you are absolutely certain you are going to hit something and nothing you can do will either let you avoid it or choose to go into something slightly less hard. Admitably if you are heading towards a 12 foot high concrete wall and have a little bit of oversteer you probably don't want to try and pull the car straight, in the circumstance your talking about you want to do anything you can to remove energy from the car so spinning will actually help you to slow down, of course we're assuming there's nothing we can do to change the angle or way we hit this wall. Then you should probably consider killing the engine and sitting back and relaxing.

If you've got any chance of not hitting something, hitting a less hard object or even if your destined to hit something but can change how hard you're going to hit it, which in reality is 99% of the time then it would probably be wise to attempt to keep control of the vehicle. If by applying throttle you can gain control of the vehicle you can then have a far greater chance of steering round your problem or if that isn't possible you'll then be able to brake effectively and be likely to loose a lot more energy in the long run than if you had just let it spin for fear of adding power, haven't thought this through have you?

Unfortunately what you were told was the 'safe' method, in that otherwise some unintelligent idiot will end up crashing because either they stand on the throttle or decide to speed up when they think the car is sliding. It's like the advice on what to do when a trailer starts to sway, the old advice was to gradually speed up pulling the trailer straight, which makes sense, to gentle braking, which sounds pretty suicidal to me, no doubt this was changed on the basis that it's better to give incompetent drivers advice that results in a smaller accident rather than try to trust them to use common sense to prevent a crash. Unfortunately law suits are a plenty in the US, so no doubt that makes them careful what they tell you. Likewise the standard of driving in the US is very different, having recently been there I found drivers to generally be much more courteous and sensible than drivers in the UK, granted you have less traffic and bigger roads but generally the driving was much less aggressive, things like 4 way crossroads just wouldn't work in the UK because no one would ever be polite and fair on them, likewise your pedestrian crossing system and general respect for pedestrians is excellent.

However you can't park to save your lives and worst of all your general standards of car control and spacial awareness seem to be pretty non-existent, and driving around in overly power assisted automatics removes a lot of room for driver control of the vehicle, and for this reason you've obviously been taught to do something that will not help you to gain control of your vehicle, quite the opposite, but something that will remove the risk of you ending up doing something far more stupid.
Quote from sgt.flippy :This thread was about saving skids on the road. Majority now is talking about how you do it on the track to be as fast as possible. In traffic you just want to stop as quickly as possible.
They taught me to just press the clutch, brake and come to a halt. Whereas you didn't need to brake, also, clutch, and when you saved the skid, come to a halt.

thing is there are many situation in which stopping the car is unsafe
like for example skidding in traffic on the accel strip of an autobahn or any other relatively fast road

Quote from tristancliffe :Too much throttle - then don't come off the throttle, it will make things worse.

ill have to disagree with you on that one on the grounds of what axus said
if youre getting power oversteer the optimum reaction would be to lift to the point where you get 0 long slip as in lifting off the throttle a little
Quote from ajp71 :Your still talking as though you are absolutely certain you are going to hit something and nothing you can do will either let you avoid it or choose to go into something slightly less hard. Admitably if you are heading towards a 12 foot high concrete wall and have a little bit of oversteer you probably don't want to try and pull the car straight, in the circumstance your talking about you want to do anything you can to remove energy from the car so spinning will actually help you to slow down, of course we're assuming there's nothing we can do to change the angle or way we hit this wall. Then you should probably consider killing the engine and sitting back and relaxing.

If you've got any chance of not hitting something, hitting a less hard object or even if your destined to hit something but can change how hard you're going to hit it, which in reality is 99% of the time then it would probably be wise to attempt to keep control of the vehicle. If by applying throttle you can gain control of the vehicle you can then have a far greater chance of steering round your problem or if that isn't possible you'll then be able to brake effectively and be likely to loose a lot more energy in the long run than if you had just let it spin for fear of adding power, haven't thought this through have you?

Unfortunately what you were told was the 'safe' method, in that otherwise some unintelligent idiot will end up crashing because either they stand on the throttle or decide to speed up when they think the car is sliding. It's like the advice on what to do when a trailer starts to sway, the old advice was to gradually speed up pulling the trailer straight, which makes sense, to gentle braking, which sounds pretty suicidal to me, no doubt this was changed on the basis that it's better to give incompetent drivers advice that results in a smaller accident rather than try to trust them to use common sense to prevent a crash. Unfortunately law suits are a plenty in the US, so no doubt that makes them careful what they tell you. Likewise the standard of driving in the US is very different, having recently been there I found drivers to generally be much more courteous and sensible than drivers in the UK, granted you have less traffic and bigger roads but generally the driving was much less aggressive, things like 4 way crossroads just wouldn't work in the UK because no one would ever be polite and fair on them, likewise your pedestrian crossing system and general respect for pedestrians is excellent.

However you can't park to save your lives and worst of all your general standards of car control and spacial awareness seem to be pretty non-existent, and driving around in overly power assisted automatics removes a lot of room for driver control of the vehicle, and for this reason you've obviously been taught to do something that will not help you to gain control of your vehicle, quite the opposite, but something that will remove the risk of you ending up doing something far more stupid.

Thanks for writing the long response but i got to paragraph 2 until i just had to stop. Of course everything you said is true assuming what you said, "If by applying throttle you can gain control of the vehicle you can then have a far greater chance of steering round your problem or if that isn't possible you'll then be able to brake effectively and be likely to loose a lot more energy in the long run than if you had just let it spin for fear of adding power, haven't thought this through have you?"

Yea sure, thats assuming that adding power corrects the skid =].

And before you make ridiculous assumptions that you can in no way prove correct, i will help you out. I've been driving go karts, tractors, trucks and other machines since the age of 5 and am fully capable of controlling a vehicle. I don't drive an "overly powerful automatic." I drive a 5 speed Jeep Wrangler Rubicon and know fully well what it is, and is not capable of. My father built a 1966 427 AC Cobra replica and if you want to learn about car control and correcting skids, that is the car to learn in (in a safe environment) because it is incredibly easy to spin. Plus, the fact that there is no power brakes and no power steering makes it even more difficult to correct. There is no point in me arguing in this thread anymore. I've been in slides, i've recovered them. I know how to control cars on both ends of the spectrum and i don't need you to tell me i'm doing something wrong when my methods have been working fine.
Quote from ans7812 :
Yea sure, thats assuming that adding power corrects the skid =].

Yes and you were saying you had been taught/it's best to lift in any situation, when in the vast majority of times the best thing to do is to either add power, hold power steady or gradually back off. I'm still struggling to find a circumstance where lifting your foot off the throttle isn't about as appropriate as retracting your undercarriage if your coming into land a bit fast
Quote from ajp71 :Yes and you were saying you had been taught/it's best to lift in any situation, when in the vast majority of times the best thing to do is to either add power, hold power steady or gradually back off. I'm still struggling to find a circumstance where lifting your foot off the throttle isn't about as appropriate as retracting your undercarriage if your coming into land a bit fast

I'm not sure if it is correct to think about it this way but try this. You're doing a donut. Spinning around la dee da da. Now you want to stop doing a donut. Do you add more power? No. You take your foot off the throttle. Whoa the car stopped spinning. It works the same way under less extreme circumstances. (Yes i know this is a very extreme way of thinking about it)
Quote from ans7812 :I'm not sure if it is correct to think about it this way but try this. You're doing a donut. Spinning around la dee da da. Now you want to stop doing a donut. Do you add more power? No. You take your foot off the throttle. Whoa the car stopped spinning. It works the same way under less extreme circumstances. (Yes i know this is a very extreme way of thinking about it)

no it does not because during a donut there barely any fonrt/back weight shifting going on and the bit that is going on does have no effect on car handling whereas at speed the situation is completely different
Quote from Shotglass :no it does not because during a donut there barely any fonrt/back weight shifting going on and the bit that is going on does have no effect on car handling whereas at speed the situation is completely different

The front/back weight shifting is so minimal in every day driving that it probably equates to that of doing a donut. Obviously under racing conditions there is a lot of engine braking because of its high rotating speed. Driving at 35 mph in 4th gear and lifting off the throttle can in no way be compared to lifting off at high speeds before a turn.
Quote from ans7812 :The front/back weight shifting is so minimal in every day driving that it probably equates to that of doing a donut. Obviously under racing conditions there is a lot of engine braking because of its high rotating speed. Driving at 35 mph in 4th gear and lifting off the throttle can in no way be compared to lifting off at high speeds before a turn.

But oversteer is still caused by the rear tires having insufficient lateral grip, shifting weight rearward will help overcome this, applying throttle will shift the weight rearward and help to increase the lateral grip available to the tires. Of course there will be other factors that can prevent this from being true but unless you stand on the throttle in a powerful car 90% of the time this is the case.
Quote from ans7812 :And before you make ridiculous assumptions that you can in no way prove correct, i will help you out. I've been driving go karts, tractors, trucks and other machines since the age of 5 and am fully capable of controlling a vehicle. I don't drive an "overly powerful automatic." I drive a 5 speed Jeep Wrangler Rubicon and know fully well what it is, and is not capable of. My father built a 1966 427 AC Cobra replica and if you want to learn about car control and correcting skids, that is the car to learn in (in a safe environment) because it is incredibly easy to spin. Plus, the fact that there is no power brakes and no power steering makes it even more difficult to correct. There is no point in me arguing in this thread anymore. I've been in slides, i've recovered them. I know how to control cars on both ends of the spectrum and i don't need you to tell me i'm doing something wrong when my methods have been working fine.

I've driven go karts, tractors, trucks (okay, only one truck, but maybe your definition of truck is different to mine) and other machines since the age of 4 (but I was only doing gear changes or steering, because my legs/arms weren't long enough to attempt all the controls). I don't drive an overly powerful automatic. I drive a Miata, and I know fully well what it is and isn't capable of. My father built a Caterham 7, and owns a Lancia Stratos and if you want to learn about car control and correcting skids these are the cars to learn in (in a safe environment). Plus, the fact there are no power brakes or power steering makes it even more difficult to correct [sic - that last bit is tosh]. There is, therefore, no point in me arguing in this thread anymore. I've been in slides. I've recovered them. I know how to control cars on both ends of the spectrum and don't need you telling me I'm doing something wrong when my methods have been working fine

OR

lalalalalalalalalala can't hear you lalalalalalalalalalalala I've been to Skip Barbers School lalalalalalalalalalala we don't have corners in my country, but if we did I'd be the best driver there is lalalalalalalalala
Quote from ans7812 :The front/back weight shifting is so minimal in every day driving that it probably equates to that of doing a donut. Obviously under racing conditions there is a lot of engine braking because of its high rotating speed. Driving at 35 mph in 4th gear and lifting off the throttle can in no way be compared to lifting off at high speeds before a turn.

Yes it can. Both are fine. I can lift off in any car at 150mph or 30mph and know I will be okay. The difference is in turning whilst doing it, and the same would apply if you are near the limit, either at 150 or 30. Of course, you have less time to react, but the effect of engine braking whilst on the limit will be the same.
Quote from tristancliffe :Yes it can. Both are fine. I can lift off in any car at 150mph or 30mph and know I will be okay. The difference is in turning whilst doing it, and the same would apply if you are near the limit, either at 150 or 30. Of course, you have less time to react, but the effect of engine braking whilst on the limit will be the same.

@Your previous post. I thought you were a mature adult but now I am questioning myself after reading that response. I, in no way was trying to sound "better" than anyone. My point was that i've had experience, and know what i need to do in a situation. It was a really childish way to respond.

@Your last post. Get going at 20mph. Put your Miata in 5th gear. Now let go of the gas.

Now get going at 20mph again. Leave your car in 1st gear. Now let go of the gas. If you tell me that the braking is the same in both situations, there is a problem here...
Well, no duh. I would at least expect you to carry the experiment out in the correct gear. Leave you car turned off and lift off the throttle - nice and safe. Now try it at the speed of light - woah, that's a bit scary.

Go round a corner that you can only just take at 20mph (i.e. you are on the limit) in the correct gear for that corner (probably 1st). Now lift off suddenly - you will slide.

Go round a corner that you can only just take at 150mph (i.e. you are on the limit) in the correct gear for that corner (probably 5th). Now lift off suddenly - you will slide.

See how speed is irrelevant?

Usual disclaimer - applies to both road and track as the physics are the same.
And before you make ridiculous assumptions that you can in no way prove correct, i will help you out. I've been driving go karts, tractors, trucks (well a prehistoric Bedford CF will probably count here) and other machines since the age of 5 and am fully capable of controlling a vehicle. I don't drive an "overly powerful automatic." I drive a 5 speed Ford Focus and know fully well what it is, and is not capable of. My father built a 1959 Morris Minor 1000 and if you want to learn about car control and correcting skids, that is the car to learn in (in a safe environment) because it is incredibly easy to spin (no it's not). Plus, the fact that there is no power brakes and no power steering makes it even more difficult to correct (no it makes it harder for you to retardidly fight the cars natural desire to correct a slide). There is no point in me arguing in this thread anymore. I've been in slides, i've recovered them. I know how to control cars on both ends of the spectrum and i don't need you to tell me i'm doing something wrong when my methods have been working fine.

...willy waving over.

Quote from ans7812 :
@Your last post. Get going at 20mph. Put your Miata in 5th gear. Now let go of the gas.

Well if the engine is already idling how do you suppose it's going to have an engine braking effect?
#49 - axus
ans7812, you are aware that while weight is in the process of being transfered (ie, say while you have angular velocity in the x-z plane, x being forwards and z being up) dampers push on the end of the car where weight is being transfered? So for example, you hit the brakes suddenly from full acceleration at speed. Not only do you have the difference in vertical force on the front vs back axle due to weight distribution but also due to changing weight distribution?

In LFS my instinct is always to lift off at most so much so that longitudinal acceleration becomes neutral.
Quote from ajp71 :Well if the engine is already idling how do you suppose it's going to have an engine braking effect?

My point exactly. If you are turning a corner on snow covered ground, and start to slide as a result of LOSS OF TRACTION because of the snow (turning too sharply etc.) not THROTTLE LIFT OVERSTEER, applying more throttle won't do anything because the car is ALREADY in the SLIDE. There is no SEVERE weight shift to begin with so adding throttle will only SPIN the tires even MORE.


As an aside (has nothing to do with this topic). Was driving in town today, pretty heavy rain. Waiting at a light, light turns green, about to make a left, some guy in a little crap car comes flying down the street i want to turn on, realizes the light is red, slams the breaks and tries to turn right to get out of the way. Wheels cocked hard right, slamming on the brakes only made him slide perfectly straight. Almost hit me, as soon as he let off the brakes the car turned right. Perfect example of how braking at 100% and turning at 100% is not a good mix.

Anti-skidding lessons
(120 posts, started )
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