Why is it wrong to brake and down-change simultaneously?

[MC Bodge]

I like to have my own thoughts and ideas.

[ChilliWhizz]

I've just read this whole thread from start to finish... some excellent debate on the relevance of track driving technique with regard to road safety.. much slating of 'The System', but with well balanced common sense input from BertBert explaining what it's really about Got a bit political and personal towards the end, but then this is PH

I learnt to HnT and use GBOL when I bought my first car, circa 1969, and it's as natural to me as using my mirrors and indicators. I think if someone told me it made me retarded (opposite to advanced? ) or unsafe I'd blow a fuse.

The most amazing thing about this thread though is that had the first reply to the OP's question 'Why is it wrong to brake and down-change simultaneously' been 'It isn't' it might have ended there and I probably wouldn't have spent nearly two hours reading all the interesting stuff I just have

Chilli

[25NAD90TUL]

ChilliWhizz said:

I've just read this whole thread from start to finish... some excellent debate on the relevance of track driving technique with regard to road safety.. much slating of 'The System', but with well balanced common sense input from BertBert explaining what it's really about Got a bit political and personal towards the end, but then this is PH

I learnt to HnT and use GBOL when I bought my first car, circa 1969, and it's as natural to me as using my mirrors and indicators. I think if someone told me it made me retarded (opposite to advanced? ) or unsafe I'd blow a fuse.

The most amazing thing about this thread though is that had the first reply to the OP's question 'Why is it wrong to brake and down-change simultaneously' been 'It isn't' it might have ended there and I probably wouldn't have spent nearly two hours reading all the interesting stuff I just have

Chilli

Yes some very good discussion from some very talented drivers. The system is like one of the strands of a rope or the weave of a carpet, it is a good thing to have within your fabric as a driver, of course it is only a step in a driver's career and every step brings another as they say...Some good discussion, the only thing on which we appear to agree are the words Safety, Responsibility are common to all our mantras. Smooth and Swift often occur too, balance etc etc...Of couse I myself ALWAYS play the Black knight in these discussions

ChilliWhizz said:

The most amazing thing about this thread though is that had the first reply to the OP's question 'Why is it wrong to brake and down-change simultaneously' been 'It isn't' it might have ended there

Hang on a minute...

[25NAD90TUL]

ChilliWhizz said:

I've just read this whole thread from start to finish... some excellent debate on the relevance of track driving technique with regard to road safety.. much slating of 'The System', but with well balanced common sense input from BertBert explaining what it's really about Got a bit political and personal towards the end, but then this is PH

I learnt to HnT and use GBOL when I bought my first car, circa 1969, and it's as natural to me as using my mirrors and indicators. I think if someone told me it made me retarded (opposite to advanced? ) or unsafe I'd blow a fuse.

The most amazing thing about this thread though is that had the first reply to the OP's question 'Why is it wrong to brake and down-change simultaneously' been 'It isn't' it might have ended there and I probably wouldn't have spent nearly two hours reading all the interesting stuff I just have

Chilli

It's a case of it being ok to gbol rather than rear ending a car rather than gboling or should it be double L? Overlap can be used within AD, bgol is related to your VIP passengers not spilling their Gin and Tonics, but it is a fiercely debated subject with AD, it feels very unnatural to most drivers. most in this discussion have mastered what we call 'the separation' technique and a lot feel it is very fussy and pedantic, whereas most areas of the system we are agreed upon.

I keep on threatening to leave the discussion, but never do, good stuff is in this thread from a lot of talent.

[Gary C]

25NAD90TUL said:

I can H&T well, like all forms of vehicle control, from drifting to off-roading. I am being forced to have a re-think about things, a lot of people whom I have a lot of respect for in these forums have said enough to promote a re-think on these matters.

When new ideas come through and AD is taken into it's next phase, I'll be there, ready to part with some dosh to get it down, I'm on a quest for knowledge in many areas not just driving, and if stuff like H&T is in there, I'll pass with flying colours as I do with every new challenge. There was a time when I thought I'd never warm to modern vehicle diagnostics but I did and now have a good diagnostic setup in my workshop. In the old days we listened to engines and diagnosed through pure skill and intuition, the old screwdriver to the ear trick etc, this ability is sadly lacking in modern mechanics, today many diagnostic tests in big garages end in the statement 'it might be this or it might be this...' The glory days of the backstreet garage and the junkyard genius may be gone forever.

I'm up for it, as soon as I find a course in the new style, when it emerges, I'll do a course, haven't done one in a while...Although I've been told that I shouldn't be so hung up on tests all the time as well! It's all good fun. I do learn and take ideas from this intercourse.

Hey, sounds good. Been a while since I used a screwdriver in my ear, but I know what you mean. A lot of techs now can only use the diag kit and replace what the manual tells them too. Days of stripping down a gearbox in my garage are sort of fond memories but I too have just got a lexia for our Peugeot as you can't do anything without them now.

I think the ad thing is something that would benefit most drivers on the road (including me) but when reading around the subject (not just on this thread, I became disillusioned by the number of people who acted so closed up to any different ideas.

I apologise for any offence, I did not mean to aim it at you, more at an attitude that I have seen in a number of discussions.

[25NAD90TUL]

Gary C said:

Hey, sounds good. Been a while since I used a screwdriver in my ear, but I know what you mean. A lot of techs now can only use the diag kit and replace what the manual tells them too. Days of stripping down a gearbox in my garage are sort of fond memories but I too have just got a lexia for our Peugeot as you can't do anything without them now.

I think the ad thing is something that would benefit most drivers on the road (including me) but when reading around the subject (not just on this thread, I became disillusioned by the number of people who acted so closed up to any different ideas.

I apologise for any offence, I did not mean to aim it at you, more at an attitude that I have seen in a number of discussions.

No offense taken at all. Some will use minor points to get a reaction from others, in order to get them posting on the subject in order to gain the benefit of their expertise. I tend to play that role. Not only that but arguing about bgol is a 'sport' in AD circles, I accept that to the onlooker it must seem as though it's very important, it isn't. Other points like forward obs and better hazard perception are much more crucial than a silly point on vehicle control, I think the bgol thing is more about breeding adaptability into the drive, and an awareness of what is being done at all times, most drivers here will have adapted to the separation technique, passed their test and then decided that separation is unnecessary and pedantic, which it may well be, but I see it as a training tool which breeds thought about vehicle control, in a given situation you may decide to overlap, you may decide to separate, the point is that you are making decisions about the drive, which is the required outcome.

My advice is not to get hung up on the whole bgol debate, in the scheme of things it isn't the difference between a good and bad driver, it's just a small point in the system left over from the 1930s and many see it as just that. Others such as myself may see it as a bit of flair, something a bit show-offy in the style, similarly to pull-push steering, it may not be absolutely necessary at all times, just to me, a nice demonstration of what can be achieved through thought and planning, others may use Heel and Toe and rotational or fixed input steering very skilfully, neither are 'wrong' if the desired outcomes are achieved during the drive, these minor points have little importance in the grand scheme of things.

[Toltec]

25NAD90TUL said:

Some will use minor points to get a reaction from others...

Not only that but arguing about bgol is a 'sport' in AD circles

[balls-out]

MC Bodge said:

I like to have my own thoughts and ideas.

Don't worry there is a website that can provide them.

[johnao]

25NAD90TUL said:

... similarly to pull-push steering, it may not be absolutely necessary at all times, just to me, a nice demonstration of what can be achieved through thought and planning, others may use Heel and Toe and rotational or fixed input steering very skilfully, neither are 'wrong' if the desired outcomes are achieved during the drive, these minor points have little importance in the grand scheme of things.

Hear, hear. How very sensible. If only the IAM and RoSPA examiners took the same view...

[DSS199]

boxedin said:

dunno, as a biker, its perfectly normal.

As driver, works fine whilst going downhill on twisty parts of the Route Napoleon, even more so on the N102.

Having been a biker myself i totally agree, i found in RWD cars dropping the gears can assist whilst slowing as long as you dont drop down the gears to early.

at the end of the M65 at Colne i go down the gears as i brake maybe an habit from when i rode bikes but its what makes me feel more comfortable and im never in the wrong gear for the next corner

[titian]

Why not come off the gas a little earlier and allow the car to slow down at the end of the M65 at Colne, use the brakes much less as most of the momentum has been lost by deceleration, then select the most appropriate gear to move forwards? It saves a number of gear changes and the mechanical wear associated with them, and by the way, at the end of the M65 there is often a tail back so the most appropriate gear may be first.

[R_U_LOCAL]

Modern cars - particularly modern diesels - have a couple of characteristics which in my view don't sit well with the traditional Roadcraft system approach to the transition from speed phase to gear phase.

The first is the very high top gear most modern cars seem to utilise. My 120d will cruise at motorway speeds in 6th at around 2000 RPM which is great for fuel economy, but the clash with systematic driving comes in situations as described above - when leaving a motorway or other high speed road. The idle speed of my engine is around 900 RPM so if I'm in 6th at motorway speeds and I start braking, the engine will be down to idle speed at around 40ish MPH. Traditional systematic driving would require me to dip the clutch before the engine starts to judder, but leave the car in 6th until I either stop or take a gear to go.

The trouble is, it just doesn't feel right to me to effectively coast on the brakes from 40mph. My approach is to very slightly overbrake just as the speed comes down to 40ish, then release the brakes, take an intermediate gear (4th for example), and then continue braking with the clutch engaged. In 4th, I'm then only approaching idle speed at around 15mph, from which it feels much more appropriate to dip the clutch whilst braking to a stop.

The second characteristic which I feel clashes with system is the engine design feature which causes cars to "surge" at low revs. I'm afraid I don't know the technical term for thos feature, but its especially noticable in diesel cars and is a feature in the ECU which seems to recognise when the car is about to stall, and introduces a brief surge of throttle to prevent stalling.

It seems to cause problems when applying system at fairly low speeds in urban driving. Take a left turn into a T junction as an example. The driver is travelling at 40mph, intending to turn left. The required speed for the left turn will be 10mph. Using system, the driver would brake down to the required speed without pressing the clutch, come off the brakes and then press the clutch and take 2nd gear for the turn.

The problem is, that if you've braked right down to 10mph in 4th in my car, the revs will drop below idle speed and the ECU will add a little throttle to prevent stalling. You won't notice this until you come off the brakes, but when you do, the car will accelerate slightly, just when you reallly don't want it to.

I've had to slightly adjust my technique now by dipping the clutch before I've released the brakes (only just before - its more of a blend between phases), to avoid the unintentional surge.

To be honest, I've never been a huge fan of diesel cars and I'm biting the bullet this afternoon by going to put an order down for a lovely shiny new petrol engined car!

Edited by R_U_LOCAL on Sunday 15th June 15:42

[7mike]

DSS199 said:

at the end of the M65 at Colne i go down the gears as i brake maybe an habit from when i rode bikes but its what makes me feel more comfortable and im never in the wrong gear for the next corner

titian said:

Why not come off the gas a little earlier and allow the car to slow down at the end of the M65 at Colne, use the brakes much less as most of the momentum has been lost by deceleration, then select the most appropriate gear to move forwards? It saves a number of gear changes and the mechanical wear associated with them, and by the way, at the end of the M65 there is often a tail back so the most appropriate gear may be first.

Somewhere between these two options sounds good to me. As R_U_Local said, an intermediate gear along the way might actually be a good idea. As for the end of the M65 roundabout, the most important factor for me is looking out for the pillocks behind going for the 'how fast can you go over the last brow of the hill' challenge. Quite a few have ploughed straight into the roundabout over the years & I don't want to be driving the car in their way. tbh I take the back roads & avoid that hideous bottleneck as much as possible.

[Dr Jekyll]

R_U_LOCAL said:

Modern cars - particularly modern diesels - have a couple of characteristics which in my view don't sit well with the traditional Roadcraft system approach to the transition from speed phase to gear phase.

So are manufacturers seriously expecting everyone to heel and toe?

[R_U_LOCAL]

Dr Jekyll said:

R_U_LOCAL said:

Modern cars - particularly modern diesels - have a couple of characteristics which in my view don't sit well with the traditional Roadcraft system approach to the transition from speed phase to gear phase.

So are manufacturers seriously expecting everyone to heel and toe?

I'm sorry, you've lost me. How has my post made you come to that conclusion?

[Dr Jekyll]

R_U_LOCAL said:

The trouble is, it just doesn't feel right to me to effectively coast on the brakes from 40mph. My approach is to very slightly overbrake just as the speed comes down to 40ish, then release the brakes, take an intermediate gear (4th for example), and then continue braking with the clutch engaged.

It was a question not a conclusion, but how do you take an intermediate gear during braking without H/T?

Edited by Dr Jekyll on Sunday 15th June 16:05

[R_U_LOCAL]

Dr Jekyll said:

How do you take an intermediate gear during braking without H/T?

The clue is in the bit you didn't highlight...

Reg said:

The trouble is, it just doesn't feel right to me to effectively coast on the brakes from 40mph. My approach is to very slightly overbrake just as the speed comes down to 40ish, then release the brakes, take an intermediate gear (4th for example), and then continue braking with the clutch engaged. In 4th, I'm then only approaching idle speed at around 15mph, from which it feels much more appropriate to dip the clutch whilst braking to a stop.

[Toltec]

R_U_LOCAL said:

Dr Jekyll said:

How do you take an intermediate gear during braking without H/T?

The clue is in the bit you didn't highlight...

Reg said:

The trouble is, it just doesn't feel right to me to effectively coast on the brakes from 40mph. My approach is to very slightly overbrake just as the speed comes down to 40ish, then release the brakes, take an intermediate gear (4th for example), and then continue braking with the clutch engaged. In 4th, I'm then only approaching idle speed at around 15mph, from which it feels much more appropriate to dip the clutch whilst braking to a stop.

I would let the revs get low enough so that the change does not really need a rev match then modulate the brake pedal as I lift the clutch to maintain the same overall level of braking. At least that is one way I do it, it depends on the situation really. I place more emphasis on the dynamic stability of the vehicle than separation of controls, however if I were to separate then rather than increase braking just before the change I would use a slightly higher overall brake force then taper off before the change. The intent would be to make the change at the same position and speed, but have a smoother deceleration profile.

In respect of The System if the gearchange is required and planned for then what is the problem?

[otolith]

I would imagine that the manufacturers expect people to do what most people do - downshift under braking and drag the revs up with the clutch with no attempt to rev-match.

[Don]

I'll comment on this finally.

There is absolutely nothing wrong with downchanging under braking if you can heel and toe properly.
It may save time or it may be smoother. Either way it's good.

If you can't H&T properly downchanging under braking will fk your clutch. Not today. Not tomorrow. But eventually.

Avoiding H&T and downchanging after braking may still fk your clutch if you don't bother to match revs to road speed. Not today. Not tomorrow. But eventually.

The likelihood of you being near the limit of grip and spinning into the hedge due to downchanging and braking without h&t would require you to be on a track day and trying hard.

The IAM System approach requires you to do one thing at once. Brake. Then change gear. Most people find this easier. Doesn't mean that that H&T isn't valid and effective - just that most people can't do it!

Clutch-drag braking is fking bad and no-one with any mechanical sympathy would tell you it was. This is irrelevant to the braking whilst downchanging debate other most people can't H&T.