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

[MC Bodge]

davepoth said:

I'm not going to rag on the "systems". They serve a very good purpose in getting people to think about their driving, but I believe that they should be more result oriented rather than method oriented.

Quite. The idea of "the system" is fine to give a basic plan, but using a driving system with fully discrete & never-overlapping, step-by-step phases shouldn't be seen as the "one true way" in my view. If it is, then it could well be a mis-reading of the scriptures, because although it may be a simple method, it is not always the best.


This thread has been surprisingly civilised and consensual so far. This is a good thing.

[p1esk]

davepoth said:

vonhosen said:

MC Bodge said:

vonhosen said:

But not everybody (if anybody at all) can do what's optimal for equilibrium in all circumstances & may have to do the best they can with what they have available at the time.

Agreed, but somebody separating everything out for every manoeuvre just because the IAM/Roadar/Police observer/instructor told them to -without an adequate, correct explanation of vehicle dynamics- isn't going to help much in achieving it.

Agreed

I'm not going to rag on the "systems". They serve a very good purpose in getting people to think about their driving, but I believe that they should be more result oriented rather than method oriented.

Having, and religeously applying, "systems" can lead you to do less thinking rather than more, can they not?

Checklists can often be useful, but occasionally we may need to add new items to the list, rather than merely working through the existing list. Just a thought...

[vonhosen]

davepoth said:

vonhosen said:

MC Bodge said:

vonhosen said:

But not everybody (if anybody at all) can do what's optimal for equilibrium in all circumstances & may have to do the best they can with what they have available at the time.

Agreed, but somebody separating everything out for every manoeuvre just because the IAM/Roadar/Police observer/instructor told them to -without an adequate, correct explanation of vehicle dynamics- isn't going to help much in achieving it.

Agreed

I'm not going to rag on the "systems". They serve a very good purpose in getting people to think about their driving, but I believe that they should be more result oriented rather than method oriented.

I've said as much many times.

[Redlake27]

Whether racing or road driving, i've always combined the two....i find it helps to balance the car. It took me a while to learn how to heel and toe properly though...

[Nigel Worc's]

vonhosen said:

davepoth said:

vonhosen said:

MC Bodge said:

vonhosen said:

But not everybody (if anybody at all) can do what's optimal for equilibrium in all circumstances & may have to do the best they can with what they have available at the time.

Agreed, but somebody separating everything out for every manoeuvre just because the IAM/Roadar/Police observer/instructor told them to -without an adequate, correct explanation of vehicle dynamics- isn't going to help much in achieving it.

Agreed

I'm not going to rag on the "systems". They serve a very good purpose in getting people to think about their driving, but I believe that they should be more result oriented rather than method oriented.

I've said as much many times.

And me !

[SVS]

Interestingly for some, both 'Motorcycle Roadcraft' and 'How to be a Better Rider' advocate brake/gear overlap, i.e. gear change at the end of braking.

It's only car drivers who get all het up about brake/gear separation.

[DaineseMan]

SVS said:

Interestingly for some, both 'Motorcycle Roadcraft' and 'How to be a Better Rider' advocate brake/gear overlap, i.e. gear change at the end of braking.

It's only car drivers who get all het up about brake/gear separation.

Difference with a bike though - at least when overlapping before a junction or roundabout - is that the 'braking' would usually only be on done on the rear brake , which isn't really there for slowing down and in some ways actually betters the balance of the machine.

[MC Bodge]

SVS said:

It's only car drivers who get all het up about brake/gear separation.

I suspect that is something that has become a 'pillar'/'badge of pride' of the "advanced driving community", rather than something that is actually important.

It's interesting to note how widely held (on here) the "overlapping is actually ok" view is, and yet so many people are told that it is not when they encounter "advanced driving". Maybe this will change when the next generation of examiners come through?

DaineseMan said:

Difference with a bike though - at least when overlapping before a junction or roundabout - is that the 'braking' would usually only be on done on the rear brake

Not as-a-rule when I'm riding. I generally use the rear only when I'm coming to a final halt (having finished shifting), manoeuvring slowly, filtering or (as a last resort!)to tighten a line through a bend.

I do use both brakes to settle the bike into some(tightening radius?)bends.

I don't use the rear every time I slow and change gear. I use only the front for most of the time, I reckon.

Edited by MC Bodge on Monday 7th October 08:21

[7db]

MC Bodge said:

It's interesting to note how widely held (on here) the "overlapping is actually ok" view is, and yet so many people are told that it is not when they encounter "advanced driving". Maybe this will change when the next generation of examiners come through?

Many of those stating that from a position of being able to do both. "Overlapping is actually ok" isn't really an excuse not to learn how to separate and then deploy each accordingly.

[CrutyRammers]

7db said:

Many of those stating that from a position of being able to do both. "Overlapping is actually ok" isn't really an excuse not to learn how to separate and then deploy each accordingly.

A good point. In the MGB for example, I find I have to overlap as the pedal position is poor and h&t is not easily possible. Certainly good to know both.

[DaineseMan]

MC Bodge said:

I don't use the rear every time I slow and change gear. I use only the front for most of the time, I reckon.

Edited by MC Bodge on Monday 7th October 08:21

So, for example, if I'm approaching a left turn junction going from a major road to a minor road, I would do most of my braking on the approach using front brake, but by the time I would reach the overlap stage, I think I'm usually going slow enough to only be on the rear brake.

[Nigel Worc's]

DaineseMan said:

MC Bodge said:

I don't use the rear every time I slow and change gear. I use only the front for most of the time, I reckon.

Edited by MC Bodge on Monday 7th October 08:21

So, for example, if I'm approaching a left turn junction going from a major road to a minor road, I would do most of my braking on the approach using front brake, but by the time I would reach the overlap stage, I think I'm usually going slow enough to only be on the rear brake.

Depends on the bike though doesn't it ?

On mine you cannot do rear only, you can have front only, but the rear will activate both ....... I rather like this, others don't.

[Technomad]

DaineseMan said:

So, for example, if I'm approaching a left turn junction going from a major road to a minor road, I would do most of my braking on the approach using front brake, but by the time I would reach the overlap stage, I think I'm usually going slow enough to only be on the rear brake.

Of course, the same there is true for bikes as with cars - you need to adjust your driving to suit the vehicle as well as conditions and skill level. What you describe is how I would 'normally' prefer tp ride. However, my Multistrada has such an utterly ineffectual back brake that I usually end up overlapping braking with the front with gearchanges when decelerating. That's something I can carry out safely and tolerably smoothly, but I certain wouldn't be looking for a relatively inexperienced associate to be doing that - the starting point I think has to be non-overlapping actions as per IPSGA with overlap being an acquired skill that is developed for a reason - as far as I'm concerned, if someone can demonstrate the ability AND articulate a good reason for their doing it, they're OK by me.

In cars, I have a very different approach depending on which vehicle I'm driving - to slightly contradict an earlier poster, the ideal balance for a car is not when the CofG stays in the same place, it's when you are able to deliberately shift the CofG to where it will do most good for the task at hand. Example: my automatic 4x4 BMW has pretty much 50:50 static F:R weight distribution and the box itself is smart enough to pretty much manage everything as I'd want it - most of the time I"m just switching from eco to sport mode to give myself more or less instant drive & engine braking for throttle management - it's got a fair bit of body roll, so I'm usually focussed on keeping the CofG either centralised or shifted slightly to the back for stability under drive. My 911 on the other hand has roughly 40:60 F:R static weight distribution so I'm using throttle and brake to manage CofG much more actively - turning in under trail braking when travelling at any speed massively improves the steering on the 911, followed by a rapid shift to the back under acceleration to nail the tail to the floor. So overlapping AND braking through turn-in massively improves feel, kills understeer and gives a smoother ride than a non-overlapping approach. The 911 is of course about the most extreme case you can get, but learning to drive one is hugely educational about the different needs and ways of managing CofG.

[vonhosen]

Technomad said:

DaineseMan said:

So, for example, if I'm approaching a left turn junction going from a major road to a minor road, I would do most of my braking on the approach using front brake, but by the time I would reach the overlap stage, I think I'm usually going slow enough to only be on the rear brake.

Of course, the same there is true for bikes as with cars - you need to adjust your driving to suit the vehicle as well as conditions and skill level. What you describe is how I would 'normally' prefer tp ride. However, my Multistrada has such an utterly ineffectual back brake that I usually end up overlapping braking with the front with gearchanges when decelerating. That's something I can carry out safely and tolerably smoothly, but I certain wouldn't be looking for a relatively inexperienced associate to be doing that - the starting point I think has to be non-overlapping actions as per IPSGA with overlap being an acquired skill that is developed for a reason - as far as I'm concerned, if someone can demonstrate the ability AND articulate a good reason for their doing it, they're OK by me.

In cars, I have a very different approach depending on which vehicle I'm driving - to slightly contradict an earlier poster, the ideal balance for a car is not when the CofG stays in the same place, it's when you are able to deliberately shift the CofG to where it will do most good for the task at hand. Example: my automatic 4x4 BMW has pretty much 50:50 static F:R weight distribution and the box itself is smart enough to pretty much manage everything as I'd want it - most of the time I"m just switching from eco to sport mode to give myself more or less instant drive & engine braking for throttle management - it's got a fair bit of body roll, so I'm usually focussed on keeping the CofG either centralised or shifted slightly to the back for stability under drive. My 911 on the other hand has roughly 40:60 F:R static weight distribution so I'm using throttle and brake to manage CofG much more actively - turning in under trail braking when travelling at any speed massively improves the steering on the 911, followed by a rapid shift to the back under acceleration to nail the tail to the floor. So overlapping AND braking through turn-in massively improves feel, kills understeer and gives a smoother ride than a non-overlapping approach. The 911 is of course about the most extreme case you can get, but learning to drive one is hugely educational about the different needs and ways of managing CofG.

It's not just the weight, it's the footprint of the rubber at the back.

[MC Bodge]

DaineseMan said:

MC Bodge said:

I don't use the rear every time I slow and change gear. I use only the front for most of the time, I reckon.

Edited by MC Bodge on Monday 7th October 08:21

So, for example, if I'm approaching a left turn junction going from a major road to a minor road, I would do most of my braking on the approach using front brake, but by the time I would reach the overlap stage, I think I'm usually going slow enough to only be on the rear brake.

We obviously have different riding styles.

Personally, I'd be slowing with the front, changing down the gears whilst blipping the throttle (akin to heel-toe) to maintain set/balance/equilibrium and then trailing smoothly off the brake (I always aim to squeeze the brakes on and off smoothly and steadily) as I make the turn, keeping the front wheel/suspension consistently loaded. I wouldn't (generally) be off the front brake, changing gear and then turning in and rolling on the gas.

This is not in a 'race' style, just a smooth, integrated one in normal riding, in town or out in the country.

ps. I realised on the commute today that I use the rear brake quite a lot more than I'd thought, albeit not in the way that you've described.

Edited by MC Bodge on Monday 7th October 18:38

[Technomad]

vonhosen said:

It's not just the weight, it's the footprint of the rubber at the back.

I'm not convinced that that plays much (if any) part at road speeds - most modern cars are so over-tyred that if you're anywhere near the limits of traction (wet or dry) under acceleration (the case I think in point), you probably should be questioning judgement and possibly sanity. The 911's winters are the same 295 section as the summers so I can't make a useful comparison there, but the 4x4 goes from 285/255 in summer to 255 all round in winter and I can't say I've ever needed to change my driving style to accommodate the narrower rubber in that way - the only change I need to make is to deal with the greater level of understeer on the winters, and I'm not sure if that comes from the section or the design/rubber.

[pthelazyjourno]

Technomad said:

I'm not convinced that that plays much (if any) part at road speeds - most modern cars are so over-tyred that if you're anywhere near the limits of traction (wet or dry) under acceleration (the case I think in point), you probably should be questioning judgement and possibly sanity. The 911's winters are the same 295 section as the summers so I can't make a useful comparison there, but the 4x4 goes from 285/255 in summer to 255 all round in winter and I can't say I've ever needed to change my driving style to accommodate the narrower rubber in that way - the only change I need to make is to deal with the greater level of understeer on the winters, and I'm not sure if that comes from the section or the design/rubber.

Bit of a contradiction there, no?

You don't think anybody should be near the limits of traction, and haven't needed to change your driving style to avoid it, but you gave changed your driving style (presumably?) to accommodate understeer...??

If you're dealing with understeer surely you're near the limits of traction, otherwise your car would just be turning in.

[SVS]

Advanced riders should overlap, as per Motorcycle Roadcraft.

Technomad said:

... the starting point I think has to be non-overlapping actions as per IPSGA ...

How sure are you about that? I ask because Motorcycle Roadcraft states: "Pass through any intermediate gears during the later stages of any braking by the block changing method or by systematically working through the gears, engaging the appropriate gear as speed is lost."

I'd say that's crystal clear guidance that you should change gear towards the end of braking (i.e. it advocates BGOL). And if that wasn't enough, then Motorcycle Roadrcaft goes on to specify quite clearly when and how to overlap.

Block changing: "During the later stages of braking, hold in the cluth lever and change down the gears until the appropriate lower gear is selected, then release the clutch."
Sequential changing: "As speed is lost during braking, work down through each gear, engaging the next lower gear as its optimum speed range is entered."

In conclusion, I'd say that Motorcycle Roadcraft is crystal clear that advanced riders should overlap. It specifies when they should overlap (i.e. the later stages of braking) and how to overlap.

[davepoth]

Technomad said:

In cars, I have a very different approach depending on which vehicle I'm driving - to slightly contradict an earlier poster, the ideal balance for a car is not when the CofG stays in the same place, it's when you are able to deliberately shift the CofG to where it will do most good for the task at hand. Example: my automatic 4x4 BMW has pretty much 50:50 static F:R weight distribution and the box itself is smart enough to pretty much manage everything as I'd want it - most of the time I"m just switching from eco to sport mode to give myself more or less instant drive & engine braking for throttle management - it's got a fair bit of body roll, so I'm usually focussed on keeping the CofG either centralised or shifted slightly to the back for stability under drive. My 911 on the other hand has roughly 40:60 F:R static weight distribution so I'm using throttle and brake to manage CofG much more actively - turning in under trail braking when travelling at any speed massively improves the steering on the 911, followed by a rapid shift to the back under acceleration to nail the tail to the floor. So overlapping AND braking through turn-in massively improves feel, kills understeer and gives a smoother ride than a non-overlapping approach. The 911 is of course about the most extreme case you can get, but learning to drive one is hugely educational about the different needs and ways of managing CofG.

I don't think you contradict me.

The CofG for any moment in time might be anywhere in the car. All I was saying is that the car is in balance when the CofG is at a fixed point, no matter where it is in the vehicle. The 911 is probably a bit of a special case in terms of vehicle dynamics (I've not had the pleasure of driving one) but most vehicles, like your 4x4, respond well to shifting the weight around slowly and progressively, unless you're on a rally stage.

[MC Bodge]

Technomad said:

However, my Multistrada has such an utterly ineffectual back brake that I usually end up overlapping braking with the front with gearchanges when decelerating.

I'm a bit confused. Why wouldn't you wish to do that through choice?

Technomad said:

That's something I can carry out safely and tolerably smoothly, but I certain wouldn't be looking for a relatively inexperienced associate to be doing that

Why is that? What is difficult about braking with the front and changing gear at the same time? Is it the rev-matching element?

Admittedly, to do it smoothly and sympathetically, blipping the gas whilst pulling the brake lever with two fingers takes a little practice, but it isn't that difficult to get the hang of. I doubt that most riders do it though.

Technomad said:

My 911 on the other hand has roughly 40:60 F:R static weight distribution so I'm using throttle and brake to manage CofG much more actively - turning in under trail braking when travelling at any speed massively improves the steering on the 911, followed by a rapid shift to the back under acceleration to nail the tail to the floor. So overlapping AND braking through turn-in massively improves feel, kills understeer and gives a smoother ride than a non-overlapping approach. The 911 is of course about the most extreme case you can get, but learning to drive one is hugely educational about the different needs and ways of managing CofG.

I would love to try driving a 911, especially an older one.