A question of balance
Discussion
What on earth do we mean when we talk about "balance" when driving a car? It's not like you can fall off it. Well, you can fall off the road of course, but not in the same way as the organ-donors who dust off their Tamajaki ZRZ900s every April and throw themselves around the countryside at warp factor 9.
Balance is an absolutely essential ingredient of high performance driving, and it's not a skill you can learn overnight. It's one that you need to practise, and occasionally get wrong in order to learn correctly. But first off, here's my explanation of balance as applied to driving a car. And before any of you physics pedants start (you know who you are), I know the correct terms for this will include "mass", "acceleration", "force" and no end of other scientific terms, but I'll be sticking with "weight" for now, as I'm a simple man and it's a complicated subject.
Balance is the ability of a driver to control a car in such a way that the transfer of weight involved in accelerating, braking and cornering does not lead to a loss of control.
Blimey - I think I've just written a definition! *Note to self - ring the publishers of "Roadcraft" tomorrow morning*
It's fairly obvious (and actually is written in Roadcraft) that a moving car is at it's most stable when travelling in a straight line at a constant speed. Any action that the driver takes to alter that state - increasing or decreasing speed and cornering - will transfer the vehicle's weight around the car. Braking, for instance, will transfer the vehicle's weight forwards. This will have two fairly obvious outcomes - there will be more weight pressing the front tyres into the road, and less weight pushing the back tyres into the road.
Imagine for a moment that you're driving a car with two boots - a Mk1 Toyota MR2 for instance. If you went out and bought a couple of sacks of potatoes and stuck them in the front boot, then the car would handle very differently than if you put them in the rear boot. If you're a fast driver, then you're effectively shifting those sacks of spuds into the front boot every time you brake, and chucking them in the back every time you accelerate.
Now, I'm not saying that the transfer of weight is a bad thing - far from it. In fact, it's an utterly unavoidable consequence of moving a ton-and-a-half of car along a road. Without it, none of us would enjoy driving high performance cars, as it's the transfer of weight which produces the sensations of speed that we all love - the hard cornering, the shove in the back under acceleration, and the dive under braking.
No - the transfer of weight isn't the problem. What is the problem, is how you transfer that weight.
Let's look at braking first, as it's a fairly simple operation in a car (none of this twiddling hand and foot levers that the organ donors have to do) involving pressing a pedal. That's it - you just press a pedal and the car slows down.
Well, not exactly. If you just jumped on the brake pedal really hard every time you braked, you wouldn't last very long. You'd get a sore right leg, it wouldn't do your car much good, and I'd give you 10 minutes before a taxi ran up your rear. The other problem when applying the brakes as though they are a switch is that pressing the brake pedal hard and fast transfers the vehicles weight forwards hard and fast. This can unsettle the rear end of the car and leave very little front-end grip left for steering.
The correct technique when braking is to start applying the brakes gently, and then firm up the pedal pressure as you go. I'm not talking about building up the pressure over several seconds - you should be able to do it smoothly in less than a second. You can use this technique even when braking very hard - the amount of weight you're transferring forwards is just the same as if you jumped on the pedal, but if you're smooth in your brake application, that weight transfer takes slightly longer, and that's what allows you to keep better control of the car. This is what I'd describe as "balancing" the car under braking.
Whilst we're on the subject of braking, it's just as important to be smooth coming off the brakes as it is to be smooth when applying them. It's relatively easy to learn how to press the pedal smoothly, but when you're steaming on, your attention is always on "what's next?", and it's very easy to just jump off the brakes and move straight back onto the accelerator for the next corner. Don't forget that you've transferred all that weight forwards when braking, and when you come off the brakes, it will settle rearwards again. Jumping off the brake will suddenly release weight from the front of the car, and if you're entering a corner, this can be disastrous. A much better technique is to ease off the brake pedal, which moves that weight rearwards at a slower rate, and helps to keep the car balanced. My instruction to students is never "off the brakes" - it's always "ooooofffff the brakes". They look at me as though I'm retarded - granted - but they get the idea.
The same is true for acceleration. If you just jump on and off the throttle, particularly if you drive a powerful car, then the resultant weight transfer can move around too quickly and unsettle the car. Take lift-off oversteer as an example. If a driver is pressing on in a corner, close to the cars limit, and has to suddenly tighten their line, then the car is liable to start sliding. If that driver then reacts badly and lifts off the accelerator in a panic, then the weight will inevitably move towards the front of the car and, more importantly, away from the rear, which will put the car into an oversteer situation that will take some skill and clear thinking from which to recover. The average driver's usual response at this point will be to hit the brakes, which, of course, transfers more weight forwards, and will pitch the car into a spin.
In a similar situation, a good driver will feather back slightly on the throttle, and use the accelerator to move the weight around to their advantage, rather than to their disadvantage. The key, as with most aspects of performance driving, is to do it smoothly.
It's the same with steering.
I reported a fatal accident a coupe of years ago in which a young driver lost control of his car whilst negotiating a bend on an NSL road at high speed. As part of the investigation, we prepared a video of the scene to be played in court. I demonstrated that a similar car could be driven through the bend almost 20mph faster than the speed at which the young driver had lost control. It wasn't a problem because my style of driving is smooth, whereas marks at the scene showed that this lad had chucked the car into the corner, and the manner in which he'd done it had put the car out of control.
Here's another nice little line.
If you sneak up on your car and make it jump, it'll throw a strop, but if you tell it what you're going to do, and ease it into it, it'll do whatever you want.
So there you go - keep your balance.
Balance is an absolutely essential ingredient of high performance driving, and it's not a skill you can learn overnight. It's one that you need to practise, and occasionally get wrong in order to learn correctly. But first off, here's my explanation of balance as applied to driving a car. And before any of you physics pedants start (you know who you are), I know the correct terms for this will include "mass", "acceleration", "force" and no end of other scientific terms, but I'll be sticking with "weight" for now, as I'm a simple man and it's a complicated subject.
Balance is the ability of a driver to control a car in such a way that the transfer of weight involved in accelerating, braking and cornering does not lead to a loss of control.
Blimey - I think I've just written a definition! *Note to self - ring the publishers of "Roadcraft" tomorrow morning*
It's fairly obvious (and actually is written in Roadcraft) that a moving car is at it's most stable when travelling in a straight line at a constant speed. Any action that the driver takes to alter that state - increasing or decreasing speed and cornering - will transfer the vehicle's weight around the car. Braking, for instance, will transfer the vehicle's weight forwards. This will have two fairly obvious outcomes - there will be more weight pressing the front tyres into the road, and less weight pushing the back tyres into the road.
Imagine for a moment that you're driving a car with two boots - a Mk1 Toyota MR2 for instance. If you went out and bought a couple of sacks of potatoes and stuck them in the front boot, then the car would handle very differently than if you put them in the rear boot. If you're a fast driver, then you're effectively shifting those sacks of spuds into the front boot every time you brake, and chucking them in the back every time you accelerate.
Now, I'm not saying that the transfer of weight is a bad thing - far from it. In fact, it's an utterly unavoidable consequence of moving a ton-and-a-half of car along a road. Without it, none of us would enjoy driving high performance cars, as it's the transfer of weight which produces the sensations of speed that we all love - the hard cornering, the shove in the back under acceleration, and the dive under braking.
No - the transfer of weight isn't the problem. What is the problem, is how you transfer that weight.
Let's look at braking first, as it's a fairly simple operation in a car (none of this twiddling hand and foot levers that the organ donors have to do) involving pressing a pedal. That's it - you just press a pedal and the car slows down.
Well, not exactly. If you just jumped on the brake pedal really hard every time you braked, you wouldn't last very long. You'd get a sore right leg, it wouldn't do your car much good, and I'd give you 10 minutes before a taxi ran up your rear. The other problem when applying the brakes as though they are a switch is that pressing the brake pedal hard and fast transfers the vehicles weight forwards hard and fast. This can unsettle the rear end of the car and leave very little front-end grip left for steering.
The correct technique when braking is to start applying the brakes gently, and then firm up the pedal pressure as you go. I'm not talking about building up the pressure over several seconds - you should be able to do it smoothly in less than a second. You can use this technique even when braking very hard - the amount of weight you're transferring forwards is just the same as if you jumped on the pedal, but if you're smooth in your brake application, that weight transfer takes slightly longer, and that's what allows you to keep better control of the car. This is what I'd describe as "balancing" the car under braking.
Whilst we're on the subject of braking, it's just as important to be smooth coming off the brakes as it is to be smooth when applying them. It's relatively easy to learn how to press the pedal smoothly, but when you're steaming on, your attention is always on "what's next?", and it's very easy to just jump off the brakes and move straight back onto the accelerator for the next corner. Don't forget that you've transferred all that weight forwards when braking, and when you come off the brakes, it will settle rearwards again. Jumping off the brake will suddenly release weight from the front of the car, and if you're entering a corner, this can be disastrous. A much better technique is to ease off the brake pedal, which moves that weight rearwards at a slower rate, and helps to keep the car balanced. My instruction to students is never "off the brakes" - it's always "ooooofffff the brakes". They look at me as though I'm retarded - granted - but they get the idea.
The same is true for acceleration. If you just jump on and off the throttle, particularly if you drive a powerful car, then the resultant weight transfer can move around too quickly and unsettle the car. Take lift-off oversteer as an example. If a driver is pressing on in a corner, close to the cars limit, and has to suddenly tighten their line, then the car is liable to start sliding. If that driver then reacts badly and lifts off the accelerator in a panic, then the weight will inevitably move towards the front of the car and, more importantly, away from the rear, which will put the car into an oversteer situation that will take some skill and clear thinking from which to recover. The average driver's usual response at this point will be to hit the brakes, which, of course, transfers more weight forwards, and will pitch the car into a spin.
In a similar situation, a good driver will feather back slightly on the throttle, and use the accelerator to move the weight around to their advantage, rather than to their disadvantage. The key, as with most aspects of performance driving, is to do it smoothly.
It's the same with steering.
I reported a fatal accident a coupe of years ago in which a young driver lost control of his car whilst negotiating a bend on an NSL road at high speed. As part of the investigation, we prepared a video of the scene to be played in court. I demonstrated that a similar car could be driven through the bend almost 20mph faster than the speed at which the young driver had lost control. It wasn't a problem because my style of driving is smooth, whereas marks at the scene showed that this lad had chucked the car into the corner, and the manner in which he'd done it had put the car out of control.
Here's another nice little line.
If you sneak up on your car and make it jump, it'll throw a strop, but if you tell it what you're going to do, and ease it into it, it'll do whatever you want.
So there you go - keep your balance.
negative creep said:
does the car being front, rear or all wheel drive have much bearing on this?
The driven end(s) are what give a car it's tendency at the limit. As a general rule, RWD cars tend to oversteer, FWD cars tend to understeer, and 4WD cars react based on a combination of the layout of the car they are based on and the torque bias of their 4WD system.
Every car is different though - older Peugeots, for instance, are very throttle-sensitive when cornering, and will oversteer quite easily. Conversely,modern BMWs have a tendency to initially understeer when approaching the limit.
Another essential factor to consider is the position of the engine and gearbox. Older Audi Quattros used to have their engine way out over the front axle line, whereas we all know about the handling idiosyncrasies of the Porsche 911 with it's engine mounted a few inches inboard of the back bumper.
Every car has different tendencies, and a different "feel" to them. Even identical cars can feel quite different to drive. The essential technique across all car types, though, is the smooth use of the controls, and the gradual, rather than sudden application of inputs.
waremark said:
Great writing again Reg, thank you. I certainly agree with whoever said that these posts of yours should be preserved. Would you consider offering them to the Advanced Driving UK web site for preservation?
I don't have a problem with these posts being posted elsewhere - I've put them in the public domain and the more people who read them and comment on them, the better. I'd just ask that you forward me a link to where they're posted.
waremark said:
I am interested that you have not mentioned: 'balancing the car with gas in a corner' - a far more simplistic but more common use of the term 'balancing'.
Most of the Roadcraft section on cornering deals with cornering with restricted vision, where the point at which the speed should be lowest is just before corner entry. In this scenario, Roadcraft teaching is to go back on the gas gently just before turn in, to maintain speed while the distance you can see remains constant, and then to increase the gas to accelerate to a suitable pace for the next section of road as you approach the end of the corner and the distance you can see extends (in Roadcraft speak 'the limit point starts to move away more quickly'). Both my IAM and Rospa examiners have called the use of gas in the corner in this way: 'balancing the car with the accelerator'.
Do you agree with this terminology? Do you teach students to corner in this style even where there is open vision through a corner? Planning to get back on the gas just before turn in makes sure that your entry speed is low enough, and it is a comfortable style of cornering for passengers, but it contrasts with the race technique of turning in off the gas and perhaps under trail braking.
Most of the Roadcraft section on cornering deals with cornering with restricted vision, where the point at which the speed should be lowest is just before corner entry. In this scenario, Roadcraft teaching is to go back on the gas gently just before turn in, to maintain speed while the distance you can see remains constant, and then to increase the gas to accelerate to a suitable pace for the next section of road as you approach the end of the corner and the distance you can see extends (in Roadcraft speak 'the limit point starts to move away more quickly'). Both my IAM and Rospa examiners have called the use of gas in the corner in this way: 'balancing the car with the accelerator'.
Do you agree with this terminology? Do you teach students to corner in this style even where there is open vision through a corner? Planning to get back on the gas just before turn in makes sure that your entry speed is low enough, and it is a comfortable style of cornering for passengers, but it contrasts with the race technique of turning in off the gas and perhaps under trail braking.
Cornering is something I'm going to cover in some future posts. I initially wanted to get across the importance of smooth car control in high performance road driving and get people thinking about how they transfer the vehicles weight around. Balancing a car on the throttle whilst cornering is something I'll cover in the future, I promise!
freddytin said:
Another good read.
I was wondering if anyone has come across driving aids to help drivers learn the art of balancing the car ?
I was thinking along the lines of a simple dash mounted pendulum acting as a G meter.
Failing this, it's going to be a test track ,or a bike. Better still....both .
I was wondering if anyone has come across driving aids to help drivers learn the art of balancing the car ?
I was thinking along the lines of a simple dash mounted pendulum acting as a G meter.
Failing this, it's going to be a test track ,or a bike. Better still....both .
Jackie Stewart used to teach using a big shallow bowl-type-thing attached to a cars bonnet with a tennis ball in it. He used to teach people to drive around a racing circuit without the ball coming out of the bowl. I thought it was a very nice teaching aid.
Or you could drive round with a bowl of water on your knee and try to stay dry.
Whilst I'm on the subject of Jackie Stewart, although I'm of the view that a lot of track techniques should stay on the track, I am a big admirer of Sir Jackie. He has always maintained that good driving is based around a smooth driving style, and he has some very nice ways of teaching the principles of smooth driving and vehicle balance.
If any of you saw the episode of Top Gear when he taught James May how to improve his lap times around Oulton Park, there was a nice example when they were having a mid-session break. Jackie pushed May and he stumbled off balance, and then he leaned against him, pushing him just as hard, but building up gradually, and May tensed against him and didn't lose his balance.
Jackie's point was that if you sneak up on a car with an unexpected move, it'll go off-balance, but if you build up gradually into a move, the car becomes ready for it, and keeps its balance.
It was a nice visual example, and it's one I now use myself.
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