Modern gearing + BGOL
Discussion
Hi all,
I've only really been reading the Advanced Driving forum for the last few days, dragged over here by the front-page promo for Reg's e-book, which I very much enjoyed (especially the willingness to be so un-stuffy and flexible with the "rules").
I've had a good lurk and a good sift through the history, and was delighted to see all the usual arguments, I mean topics, well covered.
Here's something I've been wondering recently. It's not a new problem, but seems to be more pronounced on modern cars.
We're tanking along a DC merrily at 70mph+ in 6th in our tall-ratio TDi. We approach a busy roundabout, and we're planning to stop.
How do you all deal with the fact that, without interim downshifts, you simply cannot pull up and dip the clutch at the last minute in 6th? 6th is soooo tall, that the clutch needs dipped very early, or we're relying purely on momentum to stop it stalling.
If we come down the box on approach, we get marked down for BGOL, and having 2 braking maneuvers instead of one. If we don't come down the box, we're not in the correct gear for the engine speed, and have to dip the clutch veeeeeery early. I know that's not a bad thing as such, as you're still under control on the brakes, but it "feels" horrible to be clutch-in for so long.
So, does anyone else with a tall 6-speed TDi recognise this problem, and how do you approach it.
Cheers!
I've only really been reading the Advanced Driving forum for the last few days, dragged over here by the front-page promo for Reg's e-book, which I very much enjoyed (especially the willingness to be so un-stuffy and flexible with the "rules").
I've had a good lurk and a good sift through the history, and was delighted to see all the usual arguments, I mean topics, well covered.
Here's something I've been wondering recently. It's not a new problem, but seems to be more pronounced on modern cars.
We're tanking along a DC merrily at 70mph+ in 6th in our tall-ratio TDi. We approach a busy roundabout, and we're planning to stop.
How do you all deal with the fact that, without interim downshifts, you simply cannot pull up and dip the clutch at the last minute in 6th? 6th is soooo tall, that the clutch needs dipped very early, or we're relying purely on momentum to stop it stalling.
If we come down the box on approach, we get marked down for BGOL, and having 2 braking maneuvers instead of one. If we don't come down the box, we're not in the correct gear for the engine speed, and have to dip the clutch veeeeeery early. I know that's not a bad thing as such, as you're still under control on the brakes, but it "feels" horrible to be clutch-in for so long.
So, does anyone else with a tall 6-speed TDi recognise this problem, and how do you approach it.
Cheers!
So we're all agreed, there's no better practice taught in the books than dipping the clutch. It's definitely the advice of the advanced crowd. We don't like more than one braking move, and we don't like BGOL (except in exceptional circumstances).
Well, here's where I stick my neck out...
In my opinion, it sucks. I don't want to do 150 yards with the clutch in.
We all know that in an emergency stop you don't dip the clutch until the last possible second to stop a stall. And yet, here we are happy to do 150 yards approaching a roundabout with the clutch dipped?
I like an interim shift to 3rd around the 200 yard board, usually just in between 2 separate braking actions (very rarely H&T on the road... I don't usually feel like driving with such gusto in a TDi estate).
I'm not doing it for engine braking, I'm doing it because I think 6th gear is a stupid gear to be in at that point, and I think having the clutch dipped is a compromise in an emergency stop situation.
I'd love to know what distance from the give way line others find they have to dip the clutch (in top gear), and at what speed. If anyone happens to notice on their commute, do please chip in.
Well, here's where I stick my neck out...
In my opinion, it sucks. I don't want to do 150 yards with the clutch in.
We all know that in an emergency stop you don't dip the clutch until the last possible second to stop a stall. And yet, here we are happy to do 150 yards approaching a roundabout with the clutch dipped?
I like an interim shift to 3rd around the 200 yard board, usually just in between 2 separate braking actions (very rarely H&T on the road... I don't usually feel like driving with such gusto in a TDi estate).
I'm not doing it for engine braking, I'm doing it because I think 6th gear is a stupid gear to be in at that point, and I think having the clutch dipped is a compromise in an emergency stop situation.
I'd love to know what distance from the give way line others find they have to dip the clutch (in top gear), and at what speed. If anyone happens to notice on their commute, do please chip in.
So you agree that dipping the clutch is 'correct' and dont change down to make use of engine braking but because it feels wrong being in sixth.
If you are going to the trouble to do a midway shift to 3rd, i would heel and toe with the intention of using the engine braking to assist your deceleration. It will be smoother and at least you can say it was your plan, rather than just because it feels wrong to do it the other way. It isnt solely reserved for spirited driving. It can be done slowly to good effect
Where speed and distance are concerened, I dip the clutch just before the engine would start to struggle. This will vary depending on what I can see and my planned negotiation of wharever hazard Im presented with. Might be a fair ol' lick in some circumstances. Thats why i have a brake pedal. (And a heel if im feeling that way inclined)
Edit. Obviously the speed would be the same each time, what i mean is I may leave it later and therefore be travelling faster significantly nearer to one hazard than another given the view.
If you are going to the trouble to do a midway shift to 3rd, i would heel and toe with the intention of using the engine braking to assist your deceleration. It will be smoother and at least you can say it was your plan, rather than just because it feels wrong to do it the other way. It isnt solely reserved for spirited driving. It can be done slowly to good effect
Where speed and distance are concerened, I dip the clutch just before the engine would start to struggle. This will vary depending on what I can see and my planned negotiation of wharever hazard Im presented with. Might be a fair ol' lick in some circumstances. Thats why i have a brake pedal. (And a heel if im feeling that way inclined)
Edit. Obviously the speed would be the same each time, what i mean is I may leave it later and therefore be travelling faster significantly nearer to one hazard than another given the view.
Edited by Adamxck on Friday 14th August 08:43
I'd say this is one that needs to be tried in-car. You need to see and feel how it's done in reality. This is because so much is dependent of things like feel, timing and the individual vehicle.
I've done quite a bit of advanced training, so I drive and ride systematically. I'd argue that it's better to be flexible, not dogmatic about these things. Thus, I'm happy to take an intermediate gear on the approach to a roundabout when there's an advantage to doing so.
I've done quite a bit of advanced training, so I drive and ride systematically. I'd argue that it's better to be flexible, not dogmatic about these things. Thus, I'm happy to take an intermediate gear on the approach to a roundabout when there's an advantage to doing so.
I think we're agreeing the same points. I just wonder if anyone else feels that the point at which the engine starts to struggle has changed since the rules were made, due to the mapping of modern TDis, and the stupidly long 6th gear for economy. It's all driven by manufacturer MPG Top Trumps and emissions, but the effect is that I think one rule is now a bit out of date.
Thanks for the input.
Thanks for the input.
The answer to your question depends very much on what you want to achieve. If you're undertaking a course of instruction and looking to pass a test which requires application of the five-phase Roadcraft system, then, yes, you should remain in top gear whilst braking and then dip the clutch just as the revs drop to tickover speed.
If you're just looking to improve your own driving, then you can be less rigid in your approach and take an interim gear whilst slowing if you're uncomfortable with dipping the clutch at a point which feels too early for you.
Heck, if you're looking in the right places and it's part of a planned approach, I'm not even bothered if you knock it into neutral before you brake to a stop - you won't be putting anyone in any danger and it might feel more natural to some drivers.
But before we completely dismiss the more traditional approach, lets take a look at the advantages of the Roadcraft five-phase system within the scenario you described. To do so, I just need to correct one small part of your post:
INFORMATION
We're looking well ahead, spotting the route information boards which tell us which exit we're looking to take, looking for the visual clues to the roundabout's location - clump of street lamps, chevron boards, vehicles approaching from adjoining roads, brake lights, countdown markers etc. etc. we use that information to make a plan, which includes which lane to approach in, how we'll fit in with other traffic at the junction, how much we'll have to slow, what gear we'll need etc.
Here's the key with our plan though - it must be flexible - by which I mean that the information phase runs throughout the system and information changes all the time, so as other things come into view, or as other road users move around in front of us and behind us, we must be able to alter or change our plans to suit the changing information we're taking in.
With all roundabouts, our plan must include the fact that we may have to stop at the give way line, but we'd prefer not to unless it's absolutely necessary, so we're also looking to go. We don't make this decision at this stage - we'll make it when we're a bit closer to the junction.
POSITION
We'll decide our position on approach at an early stage. Lets say it's two lanes on approach, we're going straight ahead, it's two lanes on the exit and there are a few vehicles in lane 1 which are signalling to turn left. In this scenario, we'll choose to approach the junction in lane 2 to make a little progress.
SPEED
The speed phase can overlap with the position phase and starts as soon as we lift off the throttle and the car starts to lose speed. At 70mph+, wind resistance will bring the car's speed down quite a bit before we start to brake. Remember that the information phase runs throughout the system, so as we start to brake, we're continuing to assess the movements of vehicles at, and on the approach to the roundabout.
It's at this point where we really don't want to commit one way or the other. If you only plan to stop at this stage, you're adopting an inflexible approach which will only work if you actually do have to stop. But if you've committed to stopping, taken an intermediate gear and traffic then starts moving up ahead, you have to quickly change your plan to suit, which may mean that the intermediate gear you've just taken is too low or too high and you'll need to fluff around for a more appropriate gear.
So the Roadcraft system advises that, wherever possible, we treat the speed phase as a single phase, and we try to keep it seperated from the gear phase, which will allow us to keep our options more open in situations like this.
So we'd brake down, planning to stop but looking to go, and hold back on choosing a gear until we know we'll be able to definitely go.
This may be when we're down to 30, 20, 10, or stopped, but by delaying the decision on which gear to take - even if that means dipping the clutch in 6th at a speed which may, at first, feel wrong, then we're keeping our options open until we know it's time for the fourth phase...
GEAR
Once we've seen our opportunity to go, we'll change straight into the most appropriate gear, by which I mean one which is flexible enough to give us good acceleration, without running out of revs too quickly. 5th? 3rd? 2nd? It's up to you. Whatever's best for your car and your speed. Just one last phase to go...
ACCELERATION
Stamp on the loud pedal, light up the tyres and fire off towards the horizon. Simple.
That's the thinking behind braking in one, single gear and dipping the clutch. As I said, if you're looking to pass a course of instruction, you'll need to master it, but it's certainly not essential if you're just driving for yourself. If you get the chance to watch someone competent using the technique, it may "click" with you more than if you've just read about it.
If it helps, I'm planning on producing some new and improved YouTube videos in the not too distant future and the correct application of system will feature quite heavily in the first few films.
If you're just looking to improve your own driving, then you can be less rigid in your approach and take an interim gear whilst slowing if you're uncomfortable with dipping the clutch at a point which feels too early for you.
Heck, if you're looking in the right places and it's part of a planned approach, I'm not even bothered if you knock it into neutral before you brake to a stop - you won't be putting anyone in any danger and it might feel more natural to some drivers.
But before we completely dismiss the more traditional approach, lets take a look at the advantages of the Roadcraft five-phase system within the scenario you described. To do so, I just need to correct one small part of your post:
TartanPaint said:
We're tanking along a DC merrily at 70mph+ in 6th in our tall-ratio TDi. We approach a busy roundabout, and we're planning to stop.
We are planning to stop at the roundabout, but we're also looking to go, which is a key concept when applying the system in the circumstances you describe. So, from the beginning, lets see how we apply system to this roundabout on a dual-carriageway that we're approaching at speed in top gear. Lets go through the five phases of the system in order...INFORMATION
We're looking well ahead, spotting the route information boards which tell us which exit we're looking to take, looking for the visual clues to the roundabout's location - clump of street lamps, chevron boards, vehicles approaching from adjoining roads, brake lights, countdown markers etc. etc. we use that information to make a plan, which includes which lane to approach in, how we'll fit in with other traffic at the junction, how much we'll have to slow, what gear we'll need etc.
Here's the key with our plan though - it must be flexible - by which I mean that the information phase runs throughout the system and information changes all the time, so as other things come into view, or as other road users move around in front of us and behind us, we must be able to alter or change our plans to suit the changing information we're taking in.
With all roundabouts, our plan must include the fact that we may have to stop at the give way line, but we'd prefer not to unless it's absolutely necessary, so we're also looking to go. We don't make this decision at this stage - we'll make it when we're a bit closer to the junction.
POSITION
We'll decide our position on approach at an early stage. Lets say it's two lanes on approach, we're going straight ahead, it's two lanes on the exit and there are a few vehicles in lane 1 which are signalling to turn left. In this scenario, we'll choose to approach the junction in lane 2 to make a little progress.
SPEED
The speed phase can overlap with the position phase and starts as soon as we lift off the throttle and the car starts to lose speed. At 70mph+, wind resistance will bring the car's speed down quite a bit before we start to brake. Remember that the information phase runs throughout the system, so as we start to brake, we're continuing to assess the movements of vehicles at, and on the approach to the roundabout.
It's at this point where we really don't want to commit one way or the other. If you only plan to stop at this stage, you're adopting an inflexible approach which will only work if you actually do have to stop. But if you've committed to stopping, taken an intermediate gear and traffic then starts moving up ahead, you have to quickly change your plan to suit, which may mean that the intermediate gear you've just taken is too low or too high and you'll need to fluff around for a more appropriate gear.
So the Roadcraft system advises that, wherever possible, we treat the speed phase as a single phase, and we try to keep it seperated from the gear phase, which will allow us to keep our options more open in situations like this.
So we'd brake down, planning to stop but looking to go, and hold back on choosing a gear until we know we'll be able to definitely go.
This may be when we're down to 30, 20, 10, or stopped, but by delaying the decision on which gear to take - even if that means dipping the clutch in 6th at a speed which may, at first, feel wrong, then we're keeping our options open until we know it's time for the fourth phase...
GEAR
Once we've seen our opportunity to go, we'll change straight into the most appropriate gear, by which I mean one which is flexible enough to give us good acceleration, without running out of revs too quickly. 5th? 3rd? 2nd? It's up to you. Whatever's best for your car and your speed. Just one last phase to go...
ACCELERATION
Stamp on the loud pedal, light up the tyres and fire off towards the horizon. Simple.
That's the thinking behind braking in one, single gear and dipping the clutch. As I said, if you're looking to pass a course of instruction, you'll need to master it, but it's certainly not essential if you're just driving for yourself. If you get the chance to watch someone competent using the technique, it may "click" with you more than if you've just read about it.
If it helps, I'm planning on producing some new and improved YouTube videos in the not too distant future and the correct application of system will feature quite heavily in the first few films.
Rog,
I have no agenda whatsoever. I happen to think that this rule is out of date with some modern cars, and wondered if there's a good way to adapt it. I'm not demanding anyone agrees with me. If they don't, or don't want to, or their car doesn't have this problem, then that's fine. I don't even have a better suggestion of what to do. I know the downsides of an interim gear change. I'm simply saying that the system for this scenario was created in a time when cars behaved differently, and for years I've had no problem with it. Then I bought a TDi with a tall 6th gear and for the first time it feels like the system is wrong for this car. in this scenario.
I'd have thought this was exactly the kind of fiddly off-message discussion that would get the community brains going.
Don't get me wrong, I know the system off by heart. I understand the concepts perfectly (regardless of my flawed human ability to execute them).
I don't believe for one minute that we shouldn't look critically at the system. It has to be revised and kept up to date. I left one advanced forum because they simply refused to entertain any discussion that their precious system was in any way flawed. That's why it's so refreshing to hear Reg talk about the practical differences between a test and the real world.
No agenda, total understanding of all sides of the problem, I just wanted to see if anyone else thought, "Oh yeah, my car does that too!"
EDIT: Sorry, didn't answer your question.
I feel dipping the clutch completely (to the floor) is less controlled. I feel dipping it just enough to stop a stall is slipping, and not mechanically sympathetic. I'm not saying either are right, wrong or otherwise. Just that all the possible solutions to the problem seem to have an element of compromise.
I have no agenda whatsoever. I happen to think that this rule is out of date with some modern cars, and wondered if there's a good way to adapt it. I'm not demanding anyone agrees with me. If they don't, or don't want to, or their car doesn't have this problem, then that's fine. I don't even have a better suggestion of what to do. I know the downsides of an interim gear change. I'm simply saying that the system for this scenario was created in a time when cars behaved differently, and for years I've had no problem with it. Then I bought a TDi with a tall 6th gear and for the first time it feels like the system is wrong for this car. in this scenario.
I'd have thought this was exactly the kind of fiddly off-message discussion that would get the community brains going.
Don't get me wrong, I know the system off by heart. I understand the concepts perfectly (regardless of my flawed human ability to execute them).
I don't believe for one minute that we shouldn't look critically at the system. It has to be revised and kept up to date. I left one advanced forum because they simply refused to entertain any discussion that their precious system was in any way flawed. That's why it's so refreshing to hear Reg talk about the practical differences between a test and the real world.
No agenda, total understanding of all sides of the problem, I just wanted to see if anyone else thought, "Oh yeah, my car does that too!"
EDIT: Sorry, didn't answer your question.
I feel dipping the clutch completely (to the floor) is less controlled. I feel dipping it just enough to stop a stall is slipping, and not mechanically sympathetic. I'm not saying either are right, wrong or otherwise. Just that all the possible solutions to the problem seem to have an element of compromise.
Edited by TartanPaint on Friday 14th August 09:43
R_U_LOCAL said:
We are planning to stop at the roundabout, but we're also looking to go, which is a key concept when applying the system in the circumstances you describe. So, from the beginning, lets see how we apply system to this roundabout on a dual-carriageway that we're approaching at speed in top gear. Lets go through the five phases of the system in order...
etc...
A reply from Mr Local himself. Most honour'd, I am. *doffs cap*.etc...
Thanks for the consideration given to your response too. It's exactly as expected, and a great write up of the techniques. There's a way to pass the test, and a real-world to adapt to afterwards.
I did of course deliberately leave out the "...but looking to go" in this hypothetical situation. I'm really interested in the cases where you do actually get all the way down to 0mph in 6th gear, as that's the most extreme case for this problem.
Oh, Reg, on the "swerve and return" bit in your book, your theory that it's a subconscious physical reaction to the driver's thoughts and intentions... I guess that's possible. My theory has always been that it's the same cause and effect as hazard fixation. You go where you look. I think they're simply checking their offside mirror, which causes them to steer towards the offside, and the return is them looking forwards again and correcting their course. Maybe not, maybe a bit of both. Anyway, thought I'd share.
Edited by TartanPaint on Friday 14th August 09:42
Edited by TartanPaint on Friday 14th August 09:46
TartanPaint said:
Rog,
I have no agenda whatsoever. I happen to think that this rule is out of date with some modern cars, and wondered if there's a good way to adapt it. I'm not demanding anyone agrees with me. If they don't, or don't want to, or their car doesn't have this problem, then that's fine. I don't even have a better suggestion of what to do. I know the downsides of an interim gear change. I'm simply saying that the system for this scenario was created in a time when cars behaved differently, and for years I've had no problem with it. Then I bought a TDi with a tall 6th gear and for the first time it feels like the system is wrong for this car. in this scenario.
I'd have thought this was exactly the kind of fiddly off-message discussion that would get the community brains going.
Don't get me wrong, I know the system off by heart. I understand the concepts perfectly (regardless of my flawed human ability to execute them).
I don't believe for one minute that we shouldn't look critically at the system. It has to be revised and kept up to date. I left one advanced forum because they simply refused to entertain any discussion that their precious system was in any way flawed. That's why it's so refreshing to hear Reg talk about the practical differences between a test and the real world.
No agenda, total understanding of all sides of the problem, I just wanted to see if anyone else thought, "Oh yeah, my car does that too!"
EDIT: Sorry, didn't answer your question.
I feel dipping the clutch completely (to the floor) is less controlled. I feel dipping it just enough to stop a stall is slipping, and not mechanically sympathetic. I'm not saying either are right, wrong or otherwise. Just that all the possible solutions to the problem seem to have an element of compromise.
Fair enough - no agenda - that was just my perception of a maybe = apologiesI have no agenda whatsoever. I happen to think that this rule is out of date with some modern cars, and wondered if there's a good way to adapt it. I'm not demanding anyone agrees with me. If they don't, or don't want to, or their car doesn't have this problem, then that's fine. I don't even have a better suggestion of what to do. I know the downsides of an interim gear change. I'm simply saying that the system for this scenario was created in a time when cars behaved differently, and for years I've had no problem with it. Then I bought a TDi with a tall 6th gear and for the first time it feels like the system is wrong for this car. in this scenario.
I'd have thought this was exactly the kind of fiddly off-message discussion that would get the community brains going.
Don't get me wrong, I know the system off by heart. I understand the concepts perfectly (regardless of my flawed human ability to execute them).
I don't believe for one minute that we shouldn't look critically at the system. It has to be revised and kept up to date. I left one advanced forum because they simply refused to entertain any discussion that their precious system was in any way flawed. That's why it's so refreshing to hear Reg talk about the practical differences between a test and the real world.
No agenda, total understanding of all sides of the problem, I just wanted to see if anyone else thought, "Oh yeah, my car does that too!"
EDIT: Sorry, didn't answer your question.
I feel dipping the clutch completely (to the floor) is less controlled. I feel dipping it just enough to stop a stall is slipping, and not mechanically sympathetic. I'm not saying either are right, wrong or otherwise. Just that all the possible solutions to the problem seem to have an element of compromise.
The clutch is designed to be dipped in that way - if it was not then slow reversing is going to be a big issue for everyone !!
On side note - Autos are now on the market where they hold the current gear until a muck lower gear is needed rather than go down the box in turn - it saves fuel without compromising safety in any way as well as only changing with a balanced vehicle
Quite true about autos. Good point.
So, to increase my oily-bits understanding a little...
If you dip the clutch just a little, the friction plates will slip together until the just enough load is removed from the engine to stop the stall. The load I'm referring to is the momentum which is overrunning the engine. As revs drop, the wheel speed passed through the gearbox in a high gear results in the crank being dragged down to an RPM lower than the engine can comfortably idle at. The ECU map will probably compensate for a 100rpm or so drop below idle with more fueling and some advanced ignition, until it can't drag the revs up any longer, and then you get judder.
As you say, the clutch is our tool to remove the force of momentum from the engine and reduce the strain on it.
Now, I'm interested in the purpose of just slipping the clutch enough to remove just enough of that force to avoid a stall. Are you saying you don't completely disconnect the engine from the gearbox? I would have thought that removing just enough load to keep the engine from stalling would transfer strain (if we think of the difference in the opposing forces between engine and wheel speed as a strain) to the clutch plates. Which I would say based on no evidence at all was a bad thing. If you dip the clutch completely, the drive train is split and the two sides can run at whatever speed they like with no strain.
If you don't feel any judder, that would suggest your left pedal position is beyond the bitey point and the plates are completely disconnected. So really there's no difference between "just enough" and "all the way to the floor". Or is there?
Ta in advance.
So, to increase my oily-bits understanding a little...
If you dip the clutch just a little, the friction plates will slip together until the just enough load is removed from the engine to stop the stall. The load I'm referring to is the momentum which is overrunning the engine. As revs drop, the wheel speed passed through the gearbox in a high gear results in the crank being dragged down to an RPM lower than the engine can comfortably idle at. The ECU map will probably compensate for a 100rpm or so drop below idle with more fueling and some advanced ignition, until it can't drag the revs up any longer, and then you get judder.
As you say, the clutch is our tool to remove the force of momentum from the engine and reduce the strain on it.
Now, I'm interested in the purpose of just slipping the clutch enough to remove just enough of that force to avoid a stall. Are you saying you don't completely disconnect the engine from the gearbox? I would have thought that removing just enough load to keep the engine from stalling would transfer strain (if we think of the difference in the opposing forces between engine and wheel speed as a strain) to the clutch plates. Which I would say based on no evidence at all was a bad thing. If you dip the clutch completely, the drive train is split and the two sides can run at whatever speed they like with no strain.
If you don't feel any judder, that would suggest your left pedal position is beyond the bitey point and the plates are completely disconnected. So really there's no difference between "just enough" and "all the way to the floor". Or is there?
Ta in advance.
Edited by TartanPaint on Friday 14th August 11:53
In 2015, rather than 1963, i'm going to suggest the only thing that matters is being smooth!
How ever you brake, shift gear, accelerate, lift off or whatever, i don't want to be able to feel the effect on the tyres, the car, or my ass! Acceleration and decceleration should blend together, and should be timed to co-inside with the natural frequency of the car on it's suspension (ie. you can accelerate at peak accel only once the weight of the car has shifted to the back on a rwd car etc)
I'm sure most of the std advanced techinques stem from an age where cars had heavy, low geared steering systems, woeful brakes, soggy suspension, and gears that took about a week to change. In those cases, physically separating braking and gearshifts was an advantage. In 2015, i really don't think it makes any difference tbh, even for a manual, and for a modern auto / dsc, they shift so fast they can upshift at full power and not even disturb the balance!
One point of order: If you drive a front wheel drive car, it's slippy (wet road or worse) and you are forced to do a max braking emergency stop (of course, your advanced skills mean this won't happen too often due to great observation and speed selection........ ;-) then get the clutch pushed (de-clutched) in immediately! (otherwise the ABS system is having to cope with the gear referenced inertia of the Engine and results in sub optimum tyre slip control, and a longer stopping distance)
How ever you brake, shift gear, accelerate, lift off or whatever, i don't want to be able to feel the effect on the tyres, the car, or my ass! Acceleration and decceleration should blend together, and should be timed to co-inside with the natural frequency of the car on it's suspension (ie. you can accelerate at peak accel only once the weight of the car has shifted to the back on a rwd car etc)
I'm sure most of the std advanced techinques stem from an age where cars had heavy, low geared steering systems, woeful brakes, soggy suspension, and gears that took about a week to change. In those cases, physically separating braking and gearshifts was an advantage. In 2015, i really don't think it makes any difference tbh, even for a manual, and for a modern auto / dsc, they shift so fast they can upshift at full power and not even disturb the balance!
One point of order: If you drive a front wheel drive car, it's slippy (wet road or worse) and you are forced to do a max braking emergency stop (of course, your advanced skills mean this won't happen too often due to great observation and speed selection........ ;-) then get the clutch pushed (de-clutched) in immediately! (otherwise the ABS system is having to cope with the gear referenced inertia of the Engine and results in sub optimum tyre slip control, and a longer stopping distance)
I'm not an "Advanced Driver" although I have received a weeks instruction from Police driving instructor in the past which advocated the non BGOL. I have a different take on it which is based on the desired outcome.
A desired outcome, and the constraints of the environment (other road users, sight lines, the vehicle, weather ect) should be the driver (No pun intended) of any actions, the actions themselves should not be the primary desired outcome.
In the OPs scenario, dual carriageway, 70ish mph and approaching a roundabout, the desired outcome is to negotiate the roundabout with minimum impact to the progress being made. The constraints are mostly related to safety, i.e we want to achieve our desired outcome and having an accident/near miss will not help. Other constraints include the vehicle, in this case the gearing.
Prior to commencing a course of action to achieve out desired outcome we firstly need to understand the constraints and what actions we need to undertake to achieve the desired outcome whilst operating within the constraints.
This is the information stage as stated by R_U_LOCAL.
Once we know what actions we need to undertake we need to put them in the correct order and come up with a plan.
This is first 3 parts of the OODA loop- Observation, Orientation, Decision, Action. This OODA loop should be constant, i.e it is a loop, and should be a full time driving activity.
Aside from the OODA loop, we have to:
position the vehicle
slow the vehicle
negotiate the roundabout
accelerate away
The constraints (some of) will place some more actions upon us;
Constraint- Other road users on your carriageway - Action= Slow to match their speed/expectation
Constraint- Other road users in front on your carriageway - Action=Prepare to stop if they don't proceed.
Constraint- Sight line obscuring the view Traffic approaching from the right - Action= Reduce speed/prepare to stop.
Constraint- Traffic approaching from the right- Action= Reduce speed/prepare to stop.
Constraint- Keeping the car balanced- Minimise lateral loads, smooth on the brakes smooth off the brakes ect.
Constraint- Manual Gearbox - Action= select appropriate gear to accelerate away.
Constraint- Avoid Coasting - Action= de-clutch at last safe moment before stall.
Constraint- Do one thing at a time- Action= Sequence all tasks appropriately.
If we continually apply the OODA loop, we will find that some of our own actions will, lead to more actions.
This is what we are talking about. De-clutching as the engine reaches idle, does not mitigate the constraint that we should minimise coasting. So, we have a task which remains, but with no means to do it.
The "Do one thing at a time" constraint is well understood, but what is to say we can't sequence differently and perhaps do more than one task.
Our car is a 2006 330d manual idle speed of 700rpm
MPH/1000rpm
1st 5.5mph
2nd 10.1mph
3rd 15.7mph
4th 22.4mph
5th 28.2mph
6th 33.9mph
70mph = 2065rpm
Idle speed in 6th = 25mph
If we are preparing to stop, but looking to go, this could imply 15mph at the approach to the give way sign which is not compatible with 6th gear.
If we sequence our actions and add in one more task and do that task early in the sequence so it does not add to the work load when we are near the roundabout where the OODA loop is getting a bigger work out, we can address the "minimise coasting" constraint.
If we when we lift off the accelerate, we select 4th gear, we can take that gear from 70mph (3125rpm) right down to 17 mph whilst carrying out all the other actions created by the OODA loop.
We have minimised coasting and given ourselves a gear which gives better control if required. OK, we will still need to take a lower gear before entering the roundabout (330d at idle speed would be to sluggish to pull away), or after stopping, but we were going to do that anyway.
Negatives- Our rate of deceleration will increase and we won't initially display any brake lights. Task= cover the brakes.
More engine noise. Oh well...
Just my thoughts. Fire away
A desired outcome, and the constraints of the environment (other road users, sight lines, the vehicle, weather ect) should be the driver (No pun intended) of any actions, the actions themselves should not be the primary desired outcome.
In the OPs scenario, dual carriageway, 70ish mph and approaching a roundabout, the desired outcome is to negotiate the roundabout with minimum impact to the progress being made. The constraints are mostly related to safety, i.e we want to achieve our desired outcome and having an accident/near miss will not help. Other constraints include the vehicle, in this case the gearing.
Prior to commencing a course of action to achieve out desired outcome we firstly need to understand the constraints and what actions we need to undertake to achieve the desired outcome whilst operating within the constraints.
This is the information stage as stated by R_U_LOCAL.
Once we know what actions we need to undertake we need to put them in the correct order and come up with a plan.
This is first 3 parts of the OODA loop- Observation, Orientation, Decision, Action. This OODA loop should be constant, i.e it is a loop, and should be a full time driving activity.
Aside from the OODA loop, we have to:
position the vehicle
slow the vehicle
negotiate the roundabout
accelerate away
The constraints (some of) will place some more actions upon us;
Constraint- Other road users on your carriageway - Action= Slow to match their speed/expectation
Constraint- Other road users in front on your carriageway - Action=Prepare to stop if they don't proceed.
Constraint- Sight line obscuring the view Traffic approaching from the right - Action= Reduce speed/prepare to stop.
Constraint- Traffic approaching from the right- Action= Reduce speed/prepare to stop.
Constraint- Keeping the car balanced- Minimise lateral loads, smooth on the brakes smooth off the brakes ect.
Constraint- Manual Gearbox - Action= select appropriate gear to accelerate away.
Constraint- Avoid Coasting - Action= de-clutch at last safe moment before stall.
Constraint- Do one thing at a time- Action= Sequence all tasks appropriately.
If we continually apply the OODA loop, we will find that some of our own actions will, lead to more actions.
This is what we are talking about. De-clutching as the engine reaches idle, does not mitigate the constraint that we should minimise coasting. So, we have a task which remains, but with no means to do it.
The "Do one thing at a time" constraint is well understood, but what is to say we can't sequence differently and perhaps do more than one task.
Our car is a 2006 330d manual idle speed of 700rpm
MPH/1000rpm
1st 5.5mph
2nd 10.1mph
3rd 15.7mph
4th 22.4mph
5th 28.2mph
6th 33.9mph
70mph = 2065rpm
Idle speed in 6th = 25mph
If we are preparing to stop, but looking to go, this could imply 15mph at the approach to the give way sign which is not compatible with 6th gear.
If we sequence our actions and add in one more task and do that task early in the sequence so it does not add to the work load when we are near the roundabout where the OODA loop is getting a bigger work out, we can address the "minimise coasting" constraint.
If we when we lift off the accelerate, we select 4th gear, we can take that gear from 70mph (3125rpm) right down to 17 mph whilst carrying out all the other actions created by the OODA loop.
We have minimised coasting and given ourselves a gear which gives better control if required. OK, we will still need to take a lower gear before entering the roundabout (330d at idle speed would be to sluggish to pull away), or after stopping, but we were going to do that anyway.
Negatives- Our rate of deceleration will increase and we won't initially display any brake lights. Task= cover the brakes.
More engine noise. Oh well...
Just my thoughts. Fire away
Max_Torque said:
One point of order: If you drive a front wheel drive car, it's slippy (wet road or worse) and you are forced to do a max braking emergency stop (of course, your advanced skills mean this won't happen too often due to great observation and speed selection........ ;-) then get the clutch pushed (de-clutched) in immediately! (otherwise the ABS system is having to cope with the gear referenced inertia of the Engine and results in sub optimum tyre slip control, and a longer stopping distance)
So that explains it! I was taught in '09 (at 17) to dip the clutch when performing emergency stops unless the car didn't have ABS - I came up with the theory that the engine inertia helped prevent wheel locking (if the wheels lock at - nonsense numbers ahead - 80% of max braking force with clutch depressed, and at 95% with clutch not depressed, then they'd be locked for less time with the clutch up... was my theory anyway) but not that the ABS would struggle with engine inertia.Appears I had it backwards!
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