Downshifting whilst Braking
Discussion
GetKarter said:
No, surely you can change into 2nd when the revs are matched. Just don't wait for them to fall to idle. Simple.
I never get road speed driving my engine speed through this method. It's always smooth and unnoticeable.
Maybe you take too long making your actual gear change.
That is why you will have experienced the revs falling to idle.
It should be a quick clutch in, block change, clutch out, at the correct road speed so that you catch the falling revs at the correct road speed for the gear.
I do understand that what you suggest may be possible in some circumstances and in some cars. Whilst obviously for any given road speed revs in 2nd will necessarily be much higher than 5th (meaning that you must raise revs for revs to be matched), if you are, at the same time as making the change, slowing significantly, and if your engine's flywheel is quite heavy (meaning revs fall slowly), you may just catch the revs before they fall too far.I never get road speed driving my engine speed through this method. It's always smooth and unnoticeable.
Maybe you take too long making your actual gear change.
That is why you will have experienced the revs falling to idle.
It should be a quick clutch in, block change, clutch out, at the correct road speed so that you catch the falling revs at the correct road speed for the gear.
However, your technique will fall to pieces in a car with a light flywheel, only works if you can slow down enough, and does not deal with shifting down at a constant road speed (eg, as you approach a corner using acceleration sense, and just want a lower gear for the corner without changing speed).
My guess is that, actually, if you really focus on your rev counter as you shift down using your approach, that it does sometimes fall too low. In many cars, if you are smooth with the clutch (particularly if you are also braking at the same time), you won't really notice the clutch drag as revs rise. Just because you don't notice it does not mean that you are not slipping the clutch, even if only a bit.
As for my speed of gearchanging - well I adapt it to the car and the circumstance. As ever, there is rarely one right answer.
Kind regards
Steve
Get Karter said:
Good answer.^^^
Here's a thought though for all you guys who think that if you don't match revs on every downchange you are destroying your car........
....I hope you only ever buy brand new cars, because 99% of drivers wouldn't even understand what this thread is about!
But when you buy a used car you look for signs of wear just like you look for accident damage etc & it's reflected in the price you'll be willing to pay.Here's a thought though for all you guys who think that if you don't match revs on every downchange you are destroying your car........
....I hope you only ever buy brand new cars, because 99% of drivers wouldn't even understand what this thread is about!
Still the "Advanced driving" forum isn't a "Second hand purchase" forum, it's about the art of driving.
vonhosen said:
Still the "Advanced driving" forum isn't a "Second hand purchase" forum
A large part of the argument for the 'advanced' technique of matching revs was mechanical sympathy and resultant longevity of drivetrain components. Thus my post, alluding to one's car's history was perfectly valid in this debate. Overlappers were portrayed as being car breakers, so you shouldn't stick your head in the sand when they point out you've probably bought cars from overlappers in the past.
Your simplification of my point into your above-quoted put-down is regrettable. It does, however, suggest that my point struck a nerve.
Edited by Get Karter on Thursday 21st February 11:47
Get Karter said:
vonhosen said:
Still the "Advanced driving" forum isn't a "Second hand purchase" forum
A large part of the argument for the 'advanced' technique of matching revs was mechanical sympathy and resultant longevity of drivetrain components. Thus my post, alluding to one's car's history was perfectly valid in this debate.Overlappers were portrayed as being car breakers, so you shouldn't stick your head in the sand when they point out you've probably bought cars from overlappers in the past.
vonhosen said:
But when you buy a used car you look for signs of wear just like you look for accident damage etc & it's reflected in the price you'll be willing to pay.
Get Karter said:
Your simplification of my point into your above-quoted put-down is regrettable. It does, however, suggest that my point struck a nerve.
It's not a put down & no nerve struck 
The point stands though that this particular forum is about the art of advanced driving & that could be said to be a quest for what's optimal in driver performance. The question then is what is optimal, matched revs or not ?
Edited by vonhosen on Thursday 21st February 12:05
Get Karter said:
A large part of the argument for the 'advanced' technique of matching revs was mechanical sympathy and resultant longevity of drivetrain components. Thus my post, alluding to one's car's history was perfectly valid in this debate.
Most of the arguments have been about smoothness and safety in powerful RWD cars. I'd certainly agree that dragging the clutch is unlikely to matter in modern cars, as that's what most people seem to do, it just feels nasty...IMO and all that.vonhosen said:
The point stands though that this particular forum is about the art of advanced driving
I don't think that is in dispute.But it doesn't preclude the discussion from including relevant points that are directly linked to advanced driving.
That is why mechanical sympathy was mentioned by another poster; and that led to my point about a car's previous owner being likely a non-advanced driver.
I know it is two steps from the discussion on 'advanced driving' to 'car history', but hopefully now you will see that they are linked by 'mechanical sympathy'.
Now, there was an implied point in my post also. You may have missed it, so let me spell it out.
I was suggesting that non-overlapped downchanges being advocated in the name of mechanical sympathy is a weak argument. And that those who were making such an argument, if they truly believed in their point, would not risk buying a car that had had years of overlapped gearchanges. Thus either they don't really believe that a modern car needs such supreme mechanical sympathy, or they haven't thought the whole thing through.
Only really coming to this at the end but thought i may aswell post. Of course DDc and H&T will save a bit of wear (if done properly), but i wouldn't think that's the main reason why people do it.
I also think that people saying that these techniques shouldn't be used on road etc are talking out of their proverbial. I can see no reason not to. I learnt how to do both aged 17 in my 1.0 litre Nova 'Life' on the public highway, driving along at 30mph in a straight line, changing through the gears until I got the hang of it. It is now so second nature that it would take more thought to downshift without doing it.
I don't accept that it takes any - remotely - significant more time to do than normal downshifts when sufficiently practised. I also don't accept that you have any less control of your braking when heel and toeing (unless the pedal spacing is s
te).
I tend to buy second-hand cars because I hate the first hit of depreciation and accept whatever risk there is, and I do cringe when being a passenger with somepeople who uses the clutch drag as "engine braking" or put it into 2nd gear at 60 mph on the basis that its ok because they're not engaging the clutch until doing 25mph.
I reckon most people don't think about their driving enough, and if everyone did sufficiently to practice these techniques, then the roads would be whole lot better.
I also think that people saying that these techniques shouldn't be used on road etc are talking out of their proverbial. I can see no reason not to. I learnt how to do both aged 17 in my 1.0 litre Nova 'Life' on the public highway, driving along at 30mph in a straight line, changing through the gears until I got the hang of it. It is now so second nature that it would take more thought to downshift without doing it.
I don't accept that it takes any - remotely - significant more time to do than normal downshifts when sufficiently practised. I also don't accept that you have any less control of your braking when heel and toeing (unless the pedal spacing is s
te). I tend to buy second-hand cars because I hate the first hit of depreciation and accept whatever risk there is, and I do cringe when being a passenger with somepeople who uses the clutch drag as "engine braking" or put it into 2nd gear at 60 mph on the basis that its ok because they're not engaging the clutch until doing 25mph.
I reckon most people don't think about their driving enough, and if everyone did sufficiently to practice these techniques, then the roads would be whole lot better.
Get Karter said:
vonhosen said:
The point stands though that this particular forum is about the art of advanced driving
I don't think that is in dispute.But it doesn't preclude the discussion from including relevant points that are directly linked to advanced driving.
That is why mechanical sympathy was mentioned by another poster; and that led to my point about a car's previous owner being likely a non-advanced driver.
I know it is two steps from the discussion on 'advanced driving' to 'car history', but hopefully now you will see that they are linked by 'mechanical sympathy'.
Now, there was an implied point in my post also. You may have missed it, so let me spell it out.
I was suggesting that non-overlapped downchanges being advocated in the name of mechanical sympathy is a weak argument. And that those who were making such an argument, if they truly believed in their point, would not risk buying a car that had had years of overlapped gearchanges. Thus either they don't really believe that a modern car needs such supreme mechanical sympathy, or they haven't thought the whole thing through.
When you buy a car you check it out. If it shows signs of being treated roughly by the previous owner you have the choice & power. You can accept it's mechanical state, you can walk away, or you can negotiate on the price. You aren't after all going to pay top dollar for a car that shows signs of being treated like a dog, but you may for a car that shows signs that it has been well looked after. If the clutch is on the way out you can state that you'll only consider purchasing at a reduced price or if it's replaced prior to purchase. How they've treated the clutch then becomes a non issue. All of that shows you have considered how it's been driven & have thought it through.
None of that alters the fact that matching revs is of advantage to not ever doing so.
Edited by vonhosen on Thursday 21st February 14:11
fantastic, having been away travelling, Get Karter has appeared as my alter-ego and made my arguments for me - and done it better than I would have done! Excellent
Interesting comments VH (good effort on the put down too). How do you assess clutch wear on a second hand car VH? Surely regarding Advanced Driving, the "optimum" as you put it is to leave your car at home. It increases safety (you won't kill yourself by your driving by definition) and it maximises mechanical sympathy as all the components remain unused!
But, don't I recall you saying that there isn't an optimum for Advanced Driving? It's just a system. Better than unsystematic, better than many systems (such as the one you learn to pass your driving test), but just a system. In fact a system for boggo standard drivers, not even the gifted and talented.
It would be interesting to prioritise the core tenets of Advanced Driving to find the 20% of things that have 80% of the beneficial safety effect. I wouldn't expect BGOL to be in there.
Bert
Interesting comments VH (good effort on the put down too). How do you assess clutch wear on a second hand car VH? Surely regarding Advanced Driving, the "optimum" as you put it is to leave your car at home. It increases safety (you won't kill yourself by your driving by definition) and it maximises mechanical sympathy as all the components remain unused!
But, don't I recall you saying that there isn't an optimum for Advanced Driving? It's just a system. Better than unsystematic, better than many systems (such as the one you learn to pass your driving test), but just a system. In fact a system for boggo standard drivers, not even the gifted and talented.
It would be interesting to prioritise the core tenets of Advanced Driving to find the 20% of things that have 80% of the beneficial safety effect. I wouldn't expect BGOL to be in there.
Bert
BertBert said:
fantastic, having been away travelling, Get Karter has appeared as my alter-ego and made my arguments for me - and done it better than I would have done! Excellent
Interesting comments VH (good effort on the put down too). How do you assess clutch wear on a second hand car VH? Surely regarding Advanced Driving, the "optimum" as you put it is to leave your car at home. It increases safety (you won't kill yourself by your driving by definition) and it maximises mechanical sympathy as all the components remain unused!
But, don't I recall you saying that there isn't an optimum for Advanced Driving? It's just a system. Better than unsystematic, better than many systems (such as the one you learn to pass your driving test), but just a system. In fact a system for boggo standard drivers, not even the gifted and talented.
It would be interesting to prioritise the core tenets of Advanced Driving to find the 20% of things that have 80% of the beneficial safety effect. I wouldn't expect BGOL to be in there.
Bert
You're confusing what I may have said about what the Police are taught & what I might consider optimal performance, they aren't necessarily the same thing.Interesting comments VH (good effort on the put down too). How do you assess clutch wear on a second hand car VH? Surely regarding Advanced Driving, the "optimum" as you put it is to leave your car at home. It increases safety (you won't kill yourself by your driving by definition) and it maximises mechanical sympathy as all the components remain unused!
But, don't I recall you saying that there isn't an optimum for Advanced Driving? It's just a system. Better than unsystematic, better than many systems (such as the one you learn to pass your driving test), but just a system. In fact a system for boggo standard drivers, not even the gifted and talented.
It would be interesting to prioritise the core tenets of Advanced Driving to find the 20% of things that have 80% of the beneficial safety effect. I wouldn't expect BGOL to be in there.
Bert
Dr Jekyll said:
But if you aren't heeling and toeing (heel and toeing? whatever) how do you match the revs?
Just bang it into gear and drop the clutch? That matches the revs pretty quickly! I posted the rally video clip to show that not matching revs needn't be the end of the world; even in a fairly extreme situation and with one hand on the wheel.I heel-and-toe in my day-to-day Mondeo and my trusty 205 GTi. But I drive a few other cars and in some - due to the size of my feet - I can't heel and toe. My usual technique is to change down a gear before braking (with rev matching, obviously) and then change down another gear or two at lower speeds once most of the braking's out of the way. At low road and engine speeds the affect of even an abrupt gearchange isn't sufficient to destabilise the car. And anyway, it's easy enough to release a bit of pressure on the brakes for a moment as the clutch is re-engaged if the surface is s
tty and a bit of extra caution is needed. But I really don't see the need to completely seperate braking and down-changing.waremark said:
RT106 said:
The topic's about road driving. Over-lapping gearchanges is a ridiculous thing to worry about.
But it is on the Advanced Driving forum.The 'dangers' of brake/gear overlap in road driving only apply if you're completely inept and lack even a basic understanding of car control. To me it seems bizarre to tar everyone with the same brush.
RT106 said:
If this is an advanced driving forum, why isn't everyone heel-and-toeing
Two reasons.Firstly, most advanced training stresses the benefit of separating the activities of braking and gearchanging, so it's not necessary.
Secondly, even amongst advanced drivers, a decent heel and toe gearchange (perhaps employing double declutching for good measure) isn't normally a subconscious competence...
WilliBetz said:
RT106 said:
If this is an advanced driving forum, why isn't everyone heel-and-toeing
Two reasons.Firstly, most advanced training stresses the benefit of separating the activities of braking and gearchanging, so it's not necessary.
Secondly, even amongst advanced drivers, a decent heel and toe gearchange (perhaps employing double declutching for good measure) isn't normally a subconscious competence...
Adom said:
With enough practice and use it becomes as much a subconcious competence as ordinary gearchanges.
And yet ... It is harder to do (so requiring more practice to achieve the same level of competence and implying that people who have not yet achieved this competence will have to apply more effort and do it less well).
It takes longer than an ordinary (single declutch) gear change, increasing the driver workload at a time where driver workload is typically already high.
It compromises the drivers ability to steer and brake, since the foot used for braking is also being used to operate another control, and the driver is obliged to steer with one hand for longer.
Under some circumstances the benefits can outweigh the costs. More usually they won't. To suggest that for a given person it is *always* sensible to do, is IMO mistaken thinking. To go further and suggest that *everyone* should always do it as a matter of course is fundamentally misguided IMO.
BertBert said:
vonhosen said:
You're confusing what I may have said about what the Police are taught & what I might consider optimal performance, they aren't necessarily the same thing.
Do you think there is such a thing as optimal (road) driving performance VH? How do you define it?Bert
Edited by vonhosen on Friday 22 February 13:06
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