Cornering Basics Part 5 - Controlling the Car

Cornering Basics Part 5 - Controlling the Car

Author
Discussion

R_U_LOCAL

Original Poster:

2,676 posts

207 months

Saturday 21st March 2015
quotequote all
Controlling the Car Through the Corner

I mentioned in part 4 that there was a final part to this series on cornering, and here it is.

In this last section on cornering, I’ll look at how you should operate the car’s controls as you drive through the corner. I’ll start by assuming you’ve done everything else – assessed the corner, brought the car down to the correct speed, selected the right gear, picked out your line – and you’re now just at the point where you need to drive the car through the corner, following your chosen line.

Let’s make this as simple as possible. There are only two main controls you’ll need to operate.

1. The steering.

2. The accelerator.

In operating these controls, the key aim is to maintain vehicle balance – we want to accelerate out of the corner as quickly as possible whilst maintaining grip with the road surface. This involves balancing the two main forces which are competing for the tyres grip – turning the car and accelerating the car.

When you first turn the wheel, bear in mind the principles which I described in this old post on steering – start the turn of the wheel slowly to “hint” to the car that you’re about to start turning, and then when the car starts to turn and the suspension has “taken up the slack”, you can increase the speed at which you apply the steering lock before slowing the application when you’ve applied the right amount of lock.

One thing to bear in mind is that a car’s suspension isn’t just designed to give a comfy ride or to keep the wheels attached to the car. Suspension – particularly rear suspension – is designed to help the car to negotiate corners as safely and efficiently as possible.

Using some very clever links and angles, engineers nowadays design rear suspension to include a small amount of “passive” rear-wheel steering, which means that when the car is cornering and the suspension is compressed by the cornering forces, the rear wheels will steer slightly and help the car through the corner.

It’s very subtle, but has a very real effect, and to take full advantage of this effect, it’s important that whenever you steer through a corner, you should accompany the steering with a press of the accelerator. Many people know that you should accelerate out of a corner, but most people don’t know exactly when you should press the accelerator.

The answer to that question is very simple:

You should start to press the accelerator at exactly the same time that you start to turn the steering wheel.

This might seem too early – if you’ve any track driving experience, it will definitely seem too early, as a good track driver may still be braking when they start turning the wheel – sometimes right up to the corners apex.

But, as I’ve said many times before, driving on the road is not track or competition driving, and on the road, we should have sorted our position, speed and gear before actually getting to the corner.

So, the instant you start to turn the wheel, you should balance the steering by pressing the accelerator. In a tight corner, you should only press it gently at first, to balance the car and make use of the passive rear-steering. As you approach the apex, and the corner starts to open, you can press the accelerator a little harder, and as you start to take the steering lock off and the road starts to open up, you can press it harder and harder to match the straightening of the front wheels.

I used to tell students to imagine there was a piece of string connecting the steering wheel with the accelerator. As you turn the wheel – the accelerator is pressed – almost as though they are one single control which applies steering and accelerator simultaneously.

In a faster, more open corner, you can press the accelerator harder and fire the car through the corner with a good amount of firm acceleration. Trust me on this – it’s one of the most satisfying feelings it’s possible to obtain whilst holding a steering wheel! The key – as with tighter corners – is to start pressing the accelerator immediately when you start to turn the wheel.

The slowest point in a corner should be the point where you turn in. From there, pressing the accelerator will gradually build up speed whilst settling the car on to its rear suspension, taking full advantage of the passive rear-steer and giving you maximum steering effect.

Try it next time you’re out for a drive. Take a bit more speed off for the corners, and accelerate earlier – you’ll be surprised how much better your car will feel through the bends!

kwaka jack

270 posts

171 months

Monday 23rd March 2015
quotequote all
I've really enjoyed reading all of your cornering post Reg. Learnt a few things as well to try out when I'm next home. I look forward to reading your book soon aswell.

MC Bodge

21,552 posts

174 months

Wednesday 25th March 2015
quotequote all
Another good post.

I'm a believer in turning the wheel and allowing time for the car to respond (it's a 1st order control system) too, rather than turning the wheel excessively like many people appear to do.

I must admit that I tend to be one of those who is easing off the brakes into the apex of bends, though. To keep it balanced rather than to maximise grip.

It seems normal for (possibly) most drivers to coast around bends and modern cars will tolerate it, even if it isn't getting the best out of a car.

I discovered the benefit of being on the gas through bends at a young age, *possibly* as a side-effect of trying to drive fast, though.... wink

Ps. Holding onto handlebars whilst leant over and accelerating through a bend with the front end going light is also pretty good too.

Edited by MC Bodge on Wednesday 25th March 19:12

Jon1967x

7,175 posts

123 months

Thursday 26th March 2015
quotequote all
Be good if you could expand on front v rear wheel drive and how much is to initially avoid engine braking and how much is to move weight to the rear and commence a smoothly increasing acceleration phase

I'll often trail brake into a corner where exit visibility is limited as if I do need to slow further (obstacle ahead, corner tightens unexpectedly) I feel I'm less likely to unsettle the car. If the visibility is good then a trickle of power to initially neutralise the balance which increases through the apex. But I agree, the feeling of being pushed through a corner is a great one.

C7 JFW

1,205 posts

218 months

Friday 27th March 2015
quotequote all
Good article - particularly as this focuses on road driving.

R_U_LOCAL

Original Poster:

2,676 posts

207 months

Friday 27th March 2015
quotequote all
Jon1967x said:
Be good if you could expand on front v rear wheel drive and how much is to initially avoid engine braking and how much is to move weight to the rear and commence a smoothly increasing acceleration phase
The technique is essentially the same, irrespective of whether the car is front, rear or four wheel drive.

The first thing to remember is that we're not talking about handling a car on the limit here, where we're looking to manage understeer or oversteer. This is a road technique which works best at speeds ranging from normal up to just below the limit of the cars grip. If a car is understeering, for instance, the correct response would be to lift off the throttle to transfer some weight forward onto the front wheels, increasing their grip and reducing the understeer.

Instead, what we're looking to do is to balance the car so that it's starting to accelerate the instant you turn the wheel, and continues to accelerate at an appropriate rate as you negotiate, and then exit the corner.

Accelerating as you turn the wheel will, of course, transfer some weight rearwards which gives increased grip to the rear wheels - an advantage in RWD cars and a disadvantage n FWD cars, but because we're staying within the cars limits, there will be sufficient tyre grip available to manage the weight transfer.

The real advantage of applying the accelerator early is that the previously mentioned rearward weight transfer combined with the cornering forces, results in the rear suspension's tendency to create a small amount of rear-wheel steer to work at it's most efficient - the car reacts better to the steering with a little (and sometimes a lot of) acceleration.

To put it in very simple terms, try going round a corner whilst decelerating - with no throttle whatsoever, and then try going round the same corner with some acceleration. You'll find that the car just "feels" better whilst cornering with a little acceleration - keener to turn, more responsive, dare I say it - more fun.

I used to take students out in a wallowy old Mk1 Discovery to demonstrate the technique. A car with soft, compliant suspension and long wheel travel gives a much more pronounced reaction to cornering with and without acceleration. Try it in a soft old 4X4 if you ever get a chance and you'll see what I mean.

R_U_LOCAL

Original Poster:

2,676 posts

207 months

Wednesday 8th April 2015
quotequote all
anonymous said:
[redacted]
Keeping some braking on as you turn in to the corner may be an effective method to encourage the front wheels to turn in initially, but I wouldn't recommend it for the road. On the track, you've little else to think about other than your physical actions in the car and little else to worry about other than your ultimate speed through the corner and onto the next straight. So for track driving, trail braking up to the apex whilst downchanging with a heel/toe technique is probably the best approach.

On the road, however, I'd advocate sorting everything in a straight line before you get to the turn-in point as previously described. Perhaps the only tiny change I'd make if I were drivng a rear or mid-engined car would be to make the very first initial turn of the wheel with no throttle input. This means that, after braking and changing down, there is still a little forward weight transfer (the throttle is shut so there is still a little retardation from the engine) to assist the front tyres in starting the turn.

Once the car has started turning, (by which I mean literally a fraction of a second after you've started to turn the wheel) start gently applying the throttle until you're at the apex and then increase the throttle input as the corner starts to open up.

R_U_LOCAL

Original Poster:

2,676 posts

207 months

Wednesday 8th April 2015
quotequote all
anonymous said:
[redacted]
I don't agree (you didn't think I would, did you?)

As I've stated probably hundreds of times, track driving and road driving are so different as to almost be two completely different skillsets - like comparing driving and motorcycycling, for instance. There are, of course, some similarities between driving and motorcycling - engines, clutches, tyres and stuff, but the skills required to do both are very different.

I've driven quite a bit on track (I have a dedicated track car which is used regularly) and I've done a little road driving. Despite my background, When I started track driving, I had to completely re-evaluate my driving and make a number of significant changes to my driving style, not least of which was to brake harder and later than I was initially comfortable with, and to change down and match engine revs at the same time.

Your primary aim on track is to carry as much speed into, through and - most importantly - out of every corner.

On the road, there are far too many additional variables and considerations for speed to ever be the primary consideration.

I have never felt tempted to transfer any of my track techniques to the road. I'm perfectly happy with my road cornering technique, and although it may sound like a slow and ponderous approach when you're reading about it, when you experience it put into practice properly it really isn't - I can make significant progress using my technique whilst still maintaining adequate safety margins.

I understand your point, and if you're happy with your technique, then stick with it. But at least have a go with my approach next time you're out for a drive and let me know what you think.

rich83

14,192 posts

137 months

Thursday 9th April 2015
quotequote all
I would say that you should be on the accelerator (albeit light throttle) before you turn, so the car is balanced before you steer. If you turn and "jab" the accelerator at the same time, thats when accidents happen. (IMO of course)

Toltec

7,159 posts

222 months

Thursday 9th April 2015
quotequote all
I do accelerate pre-apex on some bends, however acceleration normally only starts when I can see the exit is clear. On long corners I might go to a neutral throttle to maintain speed after the turn in. Generally all the time the vanishing point is moving towards me I'll be at least covering the brakes.

I might try your method, but I think it will feel a bit weird.

RWD cossie wil

4,295 posts

172 months

Wednesday 29th April 2015
quotequote all
anonymous said:
[redacted]
Slightly left field, but hustling a 911 along is much much easier if you keep the weight over the front of the car as you turn in, the best way I have found is to turn in on the brakes or at the very worst off the throttle, then as you apex start applying the power. Too early & you can really feel the car trying to understeer & run wide. It is amazing how different the car feels depending on your cornering technique.

It's horses for courses & obviously road driving is totally different to track driving as mentioned, my take on it is I agree with the principle of getting the weight transfer sorted early, as on a greasy wet road in most cars you don't really want to be asking the front tyres to brake & turn at the same time.

RobM77

35,349 posts

233 months

Wednesday 29th April 2015
quotequote all
RWD cossie wil said:
anonymous said:
[redacted]
Slightly left field, but hustling a 911 along is much much easier if you keep the weight over the front of the car as you turn in, the best way I have found is to turn in on the brakes or at the very worst off the throttle, then as you apex start applying the power. Too early & you can really feel the car trying to understeer & run wide. It is amazing how different the car feels depending on your cornering technique.

It's horses for courses & obviously road driving is totally different to track driving as mentioned, my take on it is I agree with the principle of getting the weight transfer sorted early, as on a greasy wet road in most cars you don't really want to be asking the front tyres to brake & turn at the same time.
Personally I regard balancing the car alongside skills such as rev matching, or being smooth etc - it's one of those things that doesn't make a major impact on safety (so isn't in the basic driving test), but it does have a small impact on safety and also shows awareness and sympathy to the car. If someone doesn't balance a car properly in a corner, and an example is as you mention above, coming off the brakes fully and then steering, for me it's like someone not rev matching, or to use an analogy it's like someone leaning on an open door supported just by its hinges - both make me cringe (even if the door won't fall off or the rear wheels won't lock).

MC Bodge

21,552 posts

174 months

Wednesday 29th April 2015
quotequote all
RobM77 said:
Personally I regard balancing the car alongside skills such as rev matching, or being smooth etc - it's one of those things that doesn't make a major impact on safety (so isn't in the basic driving test), but it does have a small impact on safety and also shows awareness and sympathy to the car. If someone doesn't balance a car properly in a corner, and an example is as you mention above, coming off the brakes fully and then steering, for me it's like someone not rev matching, or to use an analogy it's like someone leaning on an open door supported just by its hinges - both make me cringe (even if the door won't fall off or the rear wheels won't lock).
I agree, even if the coming off the brakes and then steering method is the official way.

Nigel_O

2,858 posts

218 months

Thursday 30th April 2015
quotequote all
Good article - makes a lot of sense, but I'd have to question the following extract:

R_U_LOCAL said:
.... the key aim is to maintain vehicle balance – we want to accelerate out of the corner as quickly as possible whilst maintaining grip with the road surface. This involves balancing the two main forces which are competing for the tyres grip – turning the car and accelerating the car.
Surely this cannot be correct, as in most instances, the ideal approach is to maintain a given speed around the corner, not accelerate through it (although I heartily agree with the later comment that accelerating hard through a corner is one of driving's more pleasurable moments). There are bends that I know of where if I followed this approach, I'd be entering the bend at the NSL and exiting at more than 100mph

Also - "...as quickly as possible..." suggests driving on or near the limits of grip and traction, which leaves little or no room to change speed or trajectory if something unexpected happens part way round the bend

My solution would be that (for the road) the approach should be to remove as many imbalancing forces as possible - on the assumption that to get round the corner, cornering forces are unavoidable, then the only choice the driver has is to remove any other imbalance forces - ie decelerating or accelerating. Naturally, the cornering speed should also be sufficiently low so that IF either slowing or speeding up is required, it can be executed without imbalancing the car. Pedestrians step off the kerb or animals run out of hedges on bends as well as straights wink

Clearly, for the track, its entirely different - throw it in on the brakes, collect the slide, give it the beans and hold the drift (yes, I know its not actually the fastest, but its far more fun....)

RobM77

35,349 posts

233 months

Thursday 30th April 2015
quotequote all
Nigel_O said:
Good article - makes a lot of sense, but I'd have to question the following extract:

R_U_LOCAL said:
.... the key aim is to maintain vehicle balance – we want to accelerate out of the corner as quickly as possible whilst maintaining grip with the road surface. This involves balancing the two main forces which are competing for the tyres grip – turning the car and accelerating the car.
Surely this cannot be correct, as in most instances, the ideal approach is to maintain a given speed around the corner, not accelerate through it
'Out' is not equal to 'through' (see bold text above).

In/through a corner, when the steering is still, the throttle is still. When the time comes to exit the corner and unwind the steering, you can come on the throttle at the same time in sympathy with the lessening of the steering, like the two are connected with string - you exchange one for the other basically.

Nigel_O

2,858 posts

218 months

Thursday 30th April 2015
quotequote all
Fair point

However, if a bend can be taken comfortably and safely at the speed you had chosen to do on the straights, then there is no benefit to accelerating out of the bend

I think the process of accelerating out of bends is fine if the road is clear, you're "making good progress" and are choosing to disregard the posted speed limits. However, in everyday driving, surrounded by other drivers and a multitude of hazards, accelerating out of a bend is pointless and may even be regarded as overly-aggressive by the car in front, who you will no doubt catch up with very quickly shortly after the bend

RobM77

35,349 posts

233 months

Thursday 30th April 2015
quotequote all
Nigel_O said:
Fair point

However, if a bend can be taken comfortably and safely at the speed you had chosen to do on the straights, then there is no benefit to accelerating out of the bend

I think the process of accelerating out of bends is fine if the road is clear, you're "making good progress" and are choosing to disregard the posted speed limits. However, in everyday driving, surrounded by other drivers and a multitude of hazards, accelerating out of a bend is pointless and may even be regarded as overly-aggressive by the car in front, who you will no doubt catch up with very quickly shortly after the bend
yes fair points, although following a car through a corner needs quite a large gap anyway if you're driving properly and maintaining speed, because most drivers decelerate through the corner and then start accelerating after it!

Dr Jekyll

23,820 posts

260 months

Thursday 30th April 2015
quotequote all
Nigel_O said:
Fair point

However, if a bend can be taken comfortably and safely at the speed you had chosen to do on the straights, then there is no benefit to accelerating out of the bend

I think the process of accelerating out of bends is fine if the road is clear, you're "making good progress" and are choosing to disregard the posted speed limits. However, in everyday driving, surrounded by other drivers and a multitude of hazards, accelerating out of a bend is pointless and may even be regarded as overly-aggressive by the car in front, who you will no doubt catch up with very quickly shortly after the bend
That's a big if. Generally the visibility though the bend requires a lower speed than the straights, so accelerating as the view improves, even if just up to the speed limit, is perfectly logical.

Jonsv8

7,175 posts

123 months

Thursday 30th April 2015
quotequote all
Dr Jekyll said:
That's a big if. Generally the visibility though the bend requires a lower speed than the straights, so accelerating as the view improves, even if just up to the speed limit, is perfectly logical.
I imagine we are imagining a different bend/corner. A right angled blind turn might be approached differently to an open sweeping bend and everything in between. I've said I often trail into a bend, but I imagined a tighter bend with a blind exit where I'm prepared to stop more than I'm looking to exit quickly, others that advocate taking speed off before the bend then power through as you turn may be thinking of more open corner.

R_U_LOCAL

Original Poster:

2,676 posts

207 months

Thursday 30th April 2015
quotequote all
Nigel_O said:
Fair point

However, if a bend can be taken comfortably and safely at the speed you had chosen to do on the straights, then there is no benefit to accelerating out of the bend

I think the process of accelerating out of bends is fine if the road is clear, you're "making good progress" and are choosing to disregard the posted speed limits. However, in everyday driving, surrounded by other drivers and a multitude of hazards, accelerating out of a bend is pointless and may even be regarded as overly-aggressive by the car in front, who you will no doubt catch up with very quickly shortly after the bend
I should have mentioned this point in my original post, so thanks for the reminder.

There are plenty of corners which are well sighted and which visually "open up" before you actually get to them. If you're maintaining a chosen speed, then you'd think that all you have to do is turn the wheel and maintain a constant throttle, wouldn't you?

Think about that for a moment - your car is travelling along at a constant speed. As soon as you turn the wheel, lateral forces are generated through the friction with the road surface and weight is transferred to the wheels on the outside of the turn. If you do absolutely nothing with the throttle, the increased frictional forces will cause the car to slow down. Not by much - granted - but by a few miles per hour at least. More if the corner is particularly long.

To counteract this reduction in speed, you should apply a small amount of gas - by accelerating, you counteract the cars natural tendency to slow through corners and maintain your chosen speed.

So, accelerating through bends is important, even if you just want to maintain a constant speed.