.

[TripleS]

My point isn't that braking should be intermittent, but that the car should be kept in a gear that would be responsive if you choose to accelerate.

I would describe what I aim for as the other way around - I select an appropriately responsive gear when (but not before) I choose to accelerate.

It's the question I had in mind responding to TripleS's post earlier today - if gear C is the gear you're in when you start braking, do you sometimes change down to gear B part way through braking, then after some more braking and before accelerating, change down again to gear A? If I've not misunderstood and that is sometimes your approach, what would you say you're using gear B for? And how would you do the change from C to B without braking becoming intermittent? Sacrificing rev matching or using heel & toe would seem to be the only options.

Doesn't the timing (ie block change after braking or sequential during) depend on what you're braking for? If it's a 'fixed' situation (ie me leaving the M4 at J13 in top gear slowing to stop at red traffic lights), then brake and block. But if it's a 'developing' situation, where there's a possibility the hazard will clear and acceleration will be safe, then the sequential approach works well. Doesn't it?

Yes.

Best wishes all,
Dave.

[TripleS]

Exactly! Even when 'slowing to a stop at a red light' the light might change. Also, hazards might appear behind you and require acceleration. You do not even need to go down through the gear sequently, just ensure that the engine's power is there IF you need it.

Yes, again.

BTW, do we often encounter hazards appearing behind us such that we require acceleration as a response to them? Can we not, in most cases, 'manage' the behaviour of following traffic to largely avoid these hazards?

Best wishes all,
Dave.

[GJD]

As we approach hazards they don't always remain fixed, they sometimes change as to their nature and severity. When that happens it may not be appropriate to merely brake once to get the speed right, then make only one gearchange to suit that speed.

Astraist made a similar point, and others have too, and I'm not sure I get it. Certainly hazards can change as you approach them. The System's technique of a single braking phase followed by a single gear change is intended to cope with that - one doesn't make the decision of which gear to change into prior to the start of braking. Someone driving to the IPSGA System would be continuously reassessing the Information around them and altering the PSGA part of the plan as necessary. That's not to say that someone who doesn't drive to IPSGA cannot negotiate hazards as they change - that would be nonsense - but I don't think there's inherent weakness in how the technique of a single braking phase followed by a single gearchange manages hazards that change.

My preference has long been to develop a driving style that incorporates the use of a range of simple actions that can be deployed flexibly to suit the particular situation. It seems to me that too much insistence that we should always try to apply The System tends to discourage versatility and overall capability, and indeed may even tend to make us less thoughtful about our driving; and that surely can't be good.

I think it's possible to forget that the System is a means to an end, not an end in itself, which is why I think it's important people ask questions like the one that started this thread - about why particular techniques are advocated. People asking questions like that, and the discussion that follows, helps to ensure that the advocating is backed up with good reasons and it helps people understand what benefits might be on offer so they can make informed decisions about their own driving.

I've got into this thread because this is an area of my driving I'm thinking about at the moment. Whatever I'm doing, sometimes it doesn't feel like it quite works. Other people's perspectives and descriptions of what they do is all food for thought as I ponder what I might want to do differently.

Describing what I do and reading people's responses is sometimes quite illuminating too, as I then observe in detail that aspect of my driving and sometimes realise that what I actually do and what I think I do are not always exactly the same .

[waremark]

I'm sure we're all familar with the concept of using the brakes to slow down, then making one gear change to suit our new speed. This differs from the old fashioned philosophy of changing down through the gears to aid decceleration.

One of the reasons for this that I've been taught is that it's more economical to wear out and replace brake pads that your gearbox. However, is this a valid reason? I've hardly had an annual service where I've not had to replace either a pair of pads or brake disks, but I've never had to replace a gearbox!

Is this really a valid reason for not changing down through the gears, or are there better justifications, such as not taking your hands off the wheel so frequently?

I cannot remember what has been said earlier in the thread, and I expect it has all been said, but I thought I would try to list all the reasons that come to my mind for the traditional IPSGA approach:

Both hands on the wheel until slower
Deal with one thing at a time
Have right foot available for rev-matching without need for H & T
Apply retardation through all four wheels, minimising likelihood of instability
Complete braking earlier, with extra space in reserve if braking has been misjudged
Avoid wasted effort of additional gear changes

I would be interested to know how many of us generally try to avoid BGOL, perhaps split between members of IAM/Rospa and others. Is there anybody else who would also be interested to know this, and who is clued about about how to set up a vote?

[jcochrane]

I would be interested to know how many of us generally try to avoid BGOL, perhaps split between members of IAM/Rospa and others. Is there anybody else who would also be interested to know this, and who is clued about about how to set up a vote?

I would not know how to answer that question. I will use full and partial separation as well as heal and toe. Depends on what feels right at the time. I do avoid a full overlap unless stopped or almost stopped and thus not needing an increase of rpm to match speed/gear.

[Mr Cholmondeley-Warner]

I have phases. Some days I practise separating. Other days I practise heel and toe. I'm always practising double-declutching, which makes separation even more difficult (I'm not very quick at it yet).

[7db]

I find separation easiest when I'm driving heavier vehicles and I'm really applying von's artic rule (settle into the hazard entry speed 40ft before the hazard). Best is in the work truck.

In terms of learning and changing, I find it quite hard to break down my muscle memory into the actions I'm taking. I have built-up trigger motions and blips that I don't consciously control (including the famous occasional upshift blip), and quite often couldn't tell you whether I was double-declutching or not. I find this makes it hard to tweak my habits.

At the moment I'm trying to think more about where I come off the clutch for the second time during the braking phase and getting that earlier, rather than blending with the brake coming off. The exercise I'm trying is doing multiple sequential downshifts to force myself to get (at least the first one) done earlier, but I'm all ears if anyone has suggestions.

[SteveH]

I'm sure we're all familar with the concept of using the brakes to slow down, then making one gear change to suit our new speed. This differs from the old fashioned philosophy of changing down through the gears to aid decceleration.

One of the reasons for this that I've been taught is that it's more economical to wear out and replace brake pads that your gearbox. However, is this a valid reason? I've hardly had an annual service where I've not had to replace either a pair of pads or brake disks, but I've never had to replace a gearbox!

Is this really a valid reason for not changing down through the gears, or are there better justifications, such as not taking your hands off the wheel so frequently?

Well here's my idea:

When you are using your engine to slow the vehicle down, all fuel consumption is cut off. Some vehicles display the actual fuel consumption and there you can see it- it goes to 0L/100km while the vehicle is pushing the engine (push mode). Fuel is gradually being injected up to the amount needed for idle speed thereafter.
When you use your brakes, the engine is somewhere near idle so fuel is actually being injected.
If you use the technique of approaching red traffic lights with an advanced view so you wouldn't need to stop, these push-mode periods become longer.

So in the end using your gears to slow down can save you some fuel.

Impact on the gearbox: Unless you let the clutch slip very long or go to high revs, there is no negative impact.

Impact on safety: often quoted but I think this is nanny-state thinking. Using one hand off the wheel to change gears has never been a safety issue until health & safety went mad in recent years. A good driver is in control of this. If you are not, you are not a good driver. Then you should use your brakes instead

Steph

[brianhaddon]

I'm sure we're all familar with the concept of using the brakes to slow down, then making one gear change to suit our new speed. This differs from the old fashioned philosophy of changing down through the gears to aid decceleration.

One of the reasons for this that I've been taught is that it's more economical to wear out and replace brake pads that your gearbox. However, is this a valid reason? I've hardly had an annual service where I've not had to replace either a pair of pads or brake disks, but I've never had to replace a gearbox!

Is this really a valid reason for not changing down through the gears, or are there better justifications, such as not taking your hands off the wheel so frequently?

Well here's my idea:

When you are using your engine to slow the vehicle down, all fuel consumption is cut off. Some vehicles display the actual fuel consumption and there you can see it- it goes to 0L/100km while the vehicle is pushing the engine (push mode). Fuel is gradually being injected up to the amount needed for idle speed thereafter.
When you use your brakes, the engine is somewhere near idle so fuel is actually being injected.
If you use the technique of approaching red traffic lights with an advanced view so you wouldn't need to stop, these push-mode periods become longer.

So in the end using your gears to slow down can save you some fuel.

Impact on the gearbox: Unless you let the clutch slip very long or go to high revs, there is no negative impact.

Impact on safety: often quoted but I think this is nanny-state thinking. Using one hand off the wheel to change gears has never been a safety issue until health & safety went mad in recent years. A good driver is in control of this. If you are not, you are not a good driver. Then you should use your brakes instead

Steph

I may be stupid but I don't get it. First are you saying that if you take your foot off the accelerator and leave it off all pedals you use less fuel than if you put said foot on the footbrake?
second how do you change down without clutch drag and not raising the revs? (using fuel).
Third how long does it take to slow down changing down like this? Three and a half - when do you use the brakes?
Just wondering.
Regards
Brian Haddon

[SteveH]

Well if you are not using your gears to slow down (i.e. you are not shifting down), your engine speed will go towards idle and you will press the clutch at some point. Usually from about 1200rpm more fuel is being injected again.

If you shift down, you keep the revs a bit higher (1500-2000rpm) so the fuel is cut off.

Got nothing to do with using your footbrake not not in addition...

Steph

[dombooth]

Well if you are not using your gears to slow down (i.e. you are not shifting down), your engine speed will go towards idle and you will press the clutch at some point. Usually from about 1200rpm more fuel is being injected again.

If you shift down, you keep the revs a bit higher (1500-2000rpm) so the fuel is cut off.

Got nothing to do with using your footbrake not not in addition...

Steph

But by changing down, you're using fuel..?

Dom

[GJD]

If you use the technique of approaching red traffic lights with an advanced view so you wouldn't need to stop, these push-mode periods become longer.

What you describe there sounds to me like using acceleration sense through better planning. Certainly there are occasions where, by thinking ahead, you can flow better along the road and not need to brake or change down. The question is what to do when acceleration sense is not enough. The 'brakes to slow, gears to go...' approach is to brake and ignore gears completely (other than to put the clutch in when necessary). As I see it, there are two alternatives to 'brakes to slow': to change down through the gears instead of braking, or to change down through the gears as well as braking and not all of the reasons people have been suggesting in favour of 'brakes to slow' are applicable to both alternatives, although there are some applicable to each.

From your comment in your subsequent post I think you're talking about the second alternative - changing down as well as braking. I'm not sure I quite see the fuel saving. If (either by heel & toe or by interrupting braking) you use your right foot on the gas to rev match the down change, I'd have thought that must surely use more fuel than is needed to tick over at idle? If you don't rev match then the clutch has to drag the revs up to the 1500-2000-ish that you suggest. Perhaps that doesn't require any additional fuel? Although then we're nearly back to where the OP started, with the clutch wear from the non-rev matched gear change.

[brianhaddon]

Well if you are not using your gears to slow down (i.e. you are not shifting down), your engine speed will go towards idle and you will press the clutch at some point. Usually from about 1200rpm more fuel is being injected again.

If you shift down, you keep the revs a bit higher (1500-2000rpm) so the fuel is cut off.

Got nothing to do with using your footbrake not not in addition...

Steph

Thank you for explanation. I think GJD responded in the best way. What you are describing is acceleration sense to a degree but changing down as you slow to keep the revs up when you take your foot off the accelarator. For many situations this would be a slow and not a very practical way of slowing. The speed loss must be quicker (even accounting for advanced views,etc) so braking must be included somewhere. Unless you are one of these hypermiler types then I cannot see the benefit. Indeed like GJD I can't see the savings would be that great. To me the most efficient way is to slow to speed take the gear and go. I take the point about changing situations and to be honest cannot ever remember being caught out and not having time to select a gear and go. If anyone has chosen to brake once ready to take a gear but been caught out I would like to know the circumstances.
Regards
Brian Haddon

[nigelc]

I can't see the economy in changing down. A single gear change consists of a period of engine braking (zero fuel) and maybe a couple of seconds with the engine returning to idle (a small amount of fuel).

To change down progressively there is a period, probably less than a second admittedly, during the change where the clutch is disengaged and fuel is injected. This will happen several short times rather than one longer period. During the change there are the following options:
1, A quick change and quick release of the clutch to minimise the fuel injection period but sends the passengers heading towards the windscreen.
2, A slow release of the clutch causing wear on the clutch.
3, Double-declutching or sustained revs for smooth change but that entails injecting even more fuel.

The economy argument doesn't do it for me

This thread has actually made me start thinking and analysing what I do subconsciously and I realise that I'm sort of counting down through the gears in my head. "Approach at speed limit, gently brake, below 40mph get ready for taking 3rd, below 20 ish get ready for taking 2nd etc" This way a responsive gear is only a moment away. This was the "looking to go, planning to stop" at a roundabout. The normal commentary is more about what you see and how to react rather than that level of detail.

Good this forum... makes me think even makes me think about what I think Of course my thoughts may be complete twaddle

[Slink_Pink]

This thread has actually made me start thinking and analysing what I do subconsciously and I realise that I'm sort of counting down through the gears in my head. "Approach at speed limit, gently brake, below 40mph get ready for taking 3rd, below 20 ish get ready for taking 2nd etc" This way a responsive gear is only a moment away. This was the "looking to go, planning to stop" at a roundabout. The normal commentary is more about what you see and how to react rather than that level of detail.

Good this forum... makes me think even makes me think about what I think Of course my thoughts may be complete twaddle

+1