BGOL (just a quickie)

[Lady Godiva]

I've re-read Vonhosen's explanation of BGOL, as although I try for full seperation on every single corner (unless I overlap on grounds of safety, etc,) I don't always get it right .

I can see that there is full seperation, partial overlap, and full overlap. I can also see that full seperation should be had unless you need to overlap, then it should be full overlap. However, I'm not 100% clear on why partial overlap is bad, if full is overlap is okay. Why isn't partial overlap just as okay as full overlap (where an overlap is acceptable. I'm not questioning the need to avoid or use overlaps, it's more why is a partial one wrong).

My thinking is that partial is bad because:
1) if you put the clutch in as the brake comes off, you are actually doing neither one fully.
2) If you put the clutch in as the brake comes off, you cannot control the speed (as it is often done downhill), so you may be changing while the road speed changes.
3) it may be indicative of being rushed or unplanned.

Are there others, or is this about it.

Regards
Sally

P.S. I'm quite happy to avoid overlaps, to me it is a good thing to avoid them, so I don't particularly need any justifications as to why I dont have to worry about it. I WANT to worry about it .

P.P.S. I don't want to have anyone repeat themselves from previous threads, and I realsie that this has been done to death already, but if the experts could answer with an exasperated sigh at a beginner I'm quite happy with that .

[James]

I've re-read Vonhosen's explanation of BGOL, as although I try for full seperation on every single corner (unless I overlap on grounds of safety, etc,) I don't always get it right .

I can see that there is full seperation, partial overlap, and full overlap. I can also see that full seperation should be had unless you need to overlap, then it should be full overlap. However, I'm not 100% clear on why partial overlap is bad, if full is overlap is okay. Why isn't partial overlap just as okay as full overlap (where an overlap is acceptable. I'm not questioning the need to avoid or use overlaps, it's more why is a partial one wrong).

My thinking is that partial is bad because:
1) if you put the clutch in as the brake comes off, you are actually doing neither one fully.
2) If you put the clutch in as the brake comes off, you cannot control the speed (as it is often done downhill), so you may be changing while the road speed changes.
3) it may be indicative of being rushed or unplanned.

Are there others, or is this about it.

Regards
Sally

P.S. I'm quite happy to avoid overlaps, to me it is a good thing to avoid them, so I don't particularly need any justifications as to why I dont have to worry about it. I WANT to worry about it .

P.P.S. I don't want to have anyone repeat themselves from previous threads, and I realsie that this has been done to death already, but if the experts could answer with an exasperated sigh at a beginner I'm quite happy with that .

I would suggest that partial overlap would sometimes be indicitive of poor planning. BGOL is avoided in general as it conflicts with the system. However there are occasions when it is acceptable, and one of the those occasions is when it would be safe to do so, e.g. Slowing down on a 50mph road with traffic behind you in order to enter a narrow driveway at a 90 degree angle. Here, it would be acceptable as the traffic behind you would not expect nor appalud you for slowing right down to a crawl before the bend, then come off the brakes, then take a 1st or 2nd, and then enter the corner...

So really, you are either going to totally avoid it or you are going to break the BGOL rule due to specific circumstances. A partial overlap might suggest poor planning, as the previous 2 will be acceptable for most driving scenario's. However there may be circumstances where a partial overlap may come into play, I just can't think of any.

[Gareth]

However, I'm not 100% clear on why partial overlap is bad, if full is overlap is okay.

BGOL is avoided in general as it conflicts with the system. However there are occasions when it is acceptable, and one of the those occasions is when it would be safe to do so, e.g. Slowing down on a 50mph road with traffic behind you in order to enter a narrow driveway at a 90 degree angle.

While I can and mostly do fully separate braking from changing gear, I too have wondered about the badness of a partial overlap.

If one is fully overlapping the gear change with the braking, there is potential for a jerk when lifting the clutch with the new gear engaged because the engine revs aren't necessarily matched to the road speed for the new gear.

There are three ways to overcome this. One is to arrange the braking such that the engine speed at idle matches the road speed for the new gear. Another would be to blip the throttle while still braking, and the last is to use a partial overlap so freeing up the right foot to synchronise the engine speed.

If you feel that heel and toe'ing is inappropriate on the road, (or you can't do it yet), then a partial overlap can be more mechanically sympathetic.

[James]

However, I'm not 100% clear on why partial overlap is bad, if full is overlap is okay.

BGOL is avoided in general as it conflicts with the system. However there are occasions when it is acceptable, and one of the those occasions is when it would be safe to do so, e.g. Slowing down on a 50mph road with traffic behind you in order to enter a narrow driveway at a 90 degree angle.

While I can and mostly do fully separate braking from changing gear, I too have wondered about the badness of a partial overlap.

If one is fully overlapping the gear change with the braking, there is potential for a jerk when lifting the clutch with the new gear engaged because the engine revs aren't necessarily matched to the road speed for the new gear.

There are three ways to overcome this. One is to arrange the braking such that the engine speed at idle matches the road speed for the new gear. Another would be to blip the throttle while still braking, and the last is to use a partial overlap so freeing up the right foot to synchronise the engine speed.

If you feel that heel and toe'ing is inappropriate on the road, (or you can't do it yet), then a partial overlap can be more mechanically sympathetic.

Do you know, I have never had any idea what heel and toeing is. I have had to guess that it involves braking with the left foot and using the accelerator with your right foot at the same time? Am I right? Can someone explain how this process benefits in any way?

[PeteG]

It should really be called "toe and the outside bit of your foot- ing", if I understand it correctly. I think you put your big toe on the brakes, and have your foot at an angle so you can roll straight across onto the accelerator pedal, perhaps a little of both?

As for partial overlap, I know I still do this, it's one of the things I'm trying to remove from my driving (similar to Ms Godiva, I'd say). As Von said, full overlap does feel so alien to me - I intend to go out (perhaps later tonight, even) and practice somewhere quiet.

[jont]

It should really be called "toe and the outside bit of your foot- ing", if I understand it correctly. I think you put your big toe on the brakes, and have your foot at an angle so you can roll straight across onto the accelerator pedal, perhaps a little of both?

Nearly. Styles vary somewhat, but essentially the weight of your foot is on the brake pedal, so while braking you either roll the side of your foot or ball onto the throttle so as to match the revs while you change gear. Means you can brake late and change gear without upsetting the balance of the car - mainly used for track driving. You might well avoid block shifting while using this technique as you often want the benefit of engine braking too. On the HPC youg drivers day, Steve Ivermee showed a great video with a Porsche driver doing this into every corner (on track, racing), including a 6th-1st for a hairpin (using all the intermediate gears too )

[James]

It should really be called "toe and the outside bit of your foot- ing", if I understand it correctly. I think you put your big toe on the brakes, and have your foot at an angle so you can roll straight across onto the accelerator pedal, perhaps a little of both?

Nearly. Styles vary somewhat, but essentially the weight of your foot is on the brake pedal, so while braking you either roll the side of your foot or ball onto the throttle so as to match the revs while you change gear. Means you can brake late and change gear without upsetting the balance of the car - mainly used for track driving. You might well avoid block shifting while using this technique as you often want the benefit of engine braking too. On the HPC youg drivers day, Steve Ivermee showed a great video with a Porsche driver doing this into every corner (on track, racing), including a 6th-1st for a hairpin (using all the intermediate gears too )

Block Shifting? I see about heel and toe now. Must say I have never tried it. Might give it a go tonight on the way to a call !!( )!!

I still prefer the idea of an overlap, often compensated with a slightly lower gear to really maximise revs on the exit, if you are looking for late braking and maximum progress. I know that it will mean a quick gearchange having taken the gear for the exit but I think this is a skill all on its own that when mastered can prove almost as good as the heel toe. This should of course be coupled with a smooth and sympathetic line around the corner (a straighter one).

As for the hairpin, my chosen method would be 6th to 2nd, half a turn and a yank on the handbrake, followed by steady acceleration and opposite lock... (Not the most progressive I know).

[jont]

Block Shifting?

Shifting for example 5th to 2nd without using intermediate gears. If you're heel and toeing that's an almighty shove on the gas to match the revs, and you won't have much engine braking in the process.

As for the hairpin, my chosen method would be 6th to 2nd, half a turn and a yank on the handbrake, followed by steady acceleration and opposite lock... (Not the most progressive I know).

Indeed, the "turning lever" is the technique I'd use while rallying, but I'd still use the intermediate gears to maximise braking on the way in as you're often on a loose surface where engine braking does make an appreciable difference (no ABS so you can't just heave on the anchors). Never seen a hairpin on a track so tight it needs help to get the car round though!

If you really want to see some dancing on pedals - Clicky and enjoy When his left foot is actually using the clutch rather than the brakes, you can see his right foot twitch over the throttle while he's downshifting (eg around 1m10s)

[Rick]

I tend to either heel and toe or use full seperation, the only time i do a partial seperation is when changing from 5 to 2 if i have to depress the clutch to avoid stalling. In this case i depress the clutch until the required speed then match the revs as i take 2. Although i must admit i heel and toe a lot more than i used to now

[crr003]

...If you really want to see some dancing on pedals - Clicky and enjoy

Interesting....... probably needs to come with a health warning "Don't try left foot braking on public roads!"

Another good show is "Bending the Rules" - a DVD featuring Andy Walsh, who's pretty nifty too!

[James]

Block Shifting?

Shifting for example 5th to 2nd without using intermediate gears. If you're heel and toeing that's an almighty shove on the gas to match the revs, and you won't have much engine braking in the process.

As for the hairpin, my chosen method would be 6th to 2nd, half a turn and a yank on the handbrake, followed by steady acceleration and opposite lock... (Not the most progressive I know).

Indeed, the "turning lever" is the technique I'd use while rallying, but I'd still use the intermediate gears to maximise braking on the way in as you're often on a loose surface where engine braking does make an appreciable difference (no ABS so you can't just heave on the anchors). Never seen a hairpin on a track so tight it needs help to get the car round though!

If you really want to see some dancing on pedals - Clicky and enjoy When his left foot is actually using the clutch rather than the brakes, you can see his right foot twitch over the throttle while he's downshifting (eg around 1m10s)

Block Shifting is exactly the same then as a downchange with sustained revs. I have never heard it called block shifting however. This is something I and all police drivers should do, it was what was taught to us in training. Heel and tow is something different though, something I have no experience of.

Im interested to hear you will use intermediate gears to brake. You have justfied it well by explaining that with the loose road surface you will use the gears to

[Gareth]

Im interested to hear you will use intermediate gears to brake.

I understand some track people change down through each gear (rather than block change) to reduce the chance of destroying the engine.

[jont]

Block Shifting is exactly the same then as a downchange with sustained revs. I have never heard it called block shifting however.

It may just be me that calls it that then

Im interested to hear you will use intermediate gears to brake. You have justfied it well by explaining that with the loose road surface you will use the gears to

I guess the other benefit of using intermediate gears is that if you have misread the situation you are always in the powerband of the car if you do need to get on the throttle. If you're doing a 5->2 shift, then you'll probably be at ~1/3 max rpm in 5th before you can safely shove it into second. (If you're not on the public road your priority of S's might be somewhat different from normal ).

Also as Gareth says by going through each gear you reduce the chance of over revving.

[Lady Godiva]

Do you know, I have never had any idea what heel and toeing is. I have had to guess that it involves braking with the left foot and using the accelerator with your right foot at the same time? Am I right? Can someone explain how this process benefits in any way?

Dear Police Driver

Try this, it is quite interesting http://www.trackdayracing.co.uk/heel&toe.htm

Please note, I can't do it, partly because my pedals are too far apart, partly because I haver never been taught it, and partly becuase it is difficult in size 4 with 2" heels.

Also, block shifting is shifting up OR down in a block, although seen more going down the gears than up. One good one for going up is coming down a slip road onto a Motorway, keeping in third for flexibility, then onto the motorway and the revs give accelaration up to 70mph (no faster, because that is illiegal) then straight into 5th.

Block shifting (and to some extent Heel and Toe) is mentioned in many books on Advanced Driving, so you should be staying in and reading rather than going out and enjoying yourself. Ah well, boys will be boys

Regards
Sally

[Big Err]

Do you know, I have never had any idea what heel and toeing is.

Please note, I can't do it, partly because my pedals are too far apart, partly because I haver never been taught it, and partly becuase it is difficult in size 4 with 2" heels.Sally

My feet are too big for this lark! I once had a test drive in an old Mini and found that I couldn't press the accelerate without the brake pedal being pressed and vice versa! Needless to say I didn't get far.

Eric