ADUK Archive

I'm currently reading an interesting book about how to drive "my" Porsche which advocates all the usual advanced driving stuff including the System. One section describes the use of heel 'n' toe as part of the drive and the description got me thinking as it seemed to contradict itself.

It describes the System and states that the gear change must be done when the speed is set (after all, you don't know what gear you need until you know what speed you are doing as dictated by vision). Can't argue with that. It then says for heel 'n' toe that you select the gear you need while braking firmly (no problem with that) but you continue to stay on the brakes after the gear is selected to set the speed. This seems at odds with the System as you're second guessing the speed when you get the gear, but maybe I am reading too much into it?

Anyone have any thoughts?

Chris

Yep, if you've got the speed for the hazard right & you're in the correct gear, job's a good un.

Chris, stop reading the book, go out and try it.. it makes sense and is great fun when you're getting it right!

Octy_Ross wrote:Chris, stop reading the book, go out and try it.. it makes sense and is great fun when you're getting it right!

Interestingly trying it was what was causing me problems as I had been trying to remain systematic and overlapping by coming off the brakes at the same time as the gear blip (speed set before gear) which led to quite a lack of smoothness as I'd lost the firm platform of the brakes being held on. Sounds like I need to bring the change slightly earlier so I can stay on the brakes but still arrive at the correct speed at the hazard.

Thanks folks.

Chris

ScoobyChris wrote:Sounds like I need to bring the change slightly earlier so I can stay on the brakes but still arrive at the correct speed at the hazard.

Or perhaps even more than slightly. One school of thought is that the throttle application should be made as soon as the brake pressure is at its firmest - that is, near the start of the second phase of braking, if you take a three-phase approach.

You've got me thinking about how I choose my gear when I decide to take it while braking. Because each gear will cover a range of speeds, I guess it's often possible to make a decision about which gear you'll need before you've set the exact speed for safety through the hazard - and there's always the possibility of dropping another cog as your view develops (or doesn't).

David

ScoobyChris wrote:

Octy_Ross wrote:Chris, stop reading the book, go out and try it.. it makes sense and is great fun when you're getting it right!

Interestingly trying it was what was causing me problems as I had been trying to remain systematic and overlapping by coming off the brakes at the same time as the gear blip (speed set before gear) which led to quite a lack of smoothness as I'd lost the firm platform of the brakes being held on. Sounds like I need to bring the change slightly earlier so I can stay on the brakes but still arrive at the correct speed at the hazard.

Thanks folks.

Chris

Hi

The point of "heel and toe" is so that you can brake AND down shift at the same time, meaning you can brake harder, later and still be in the correct gear to pull out of the corner/hazard etc, there is no point lifting off the brakes as you shift, that becomes little more than double-de-clutching, hence your lack of smoothness, go out and try again

Just as an aside, when i first had my HGV licence one of my first trucks was an 8 wheeled Scammel and I had our mechanic weld a side extention on the throttle pedal so that I could hit both at once, as it was a "crash" box it was much easier than brake..throttle...change...brake because when you are trying to prevent 26 ton of stone from killing you under braking down hill you need all the help you can get

Have fun

Ivor

kfae8959 wrote:...and there's always the possibility of dropping another cog as your view develops (or doesn't).

Steady...better ready the smelling salts for some here.

If I'm doing h'n't, I'm probably changing down sequentially anyway, so at the point you stop needing to brake you should be in the right gear.

ScoobyChris wrote:It describes the System and states that the gear change must be done when the speed is set (after all, you don't know what gear you need until you know what speed you are doing as dictated by vision). Can't argue with that. It then says for heel 'n' toe that you select the gear you need while braking firmly (no problem with that) but you continue to stay on the brakes after the gear is selected to set the speed. This seems at odds with the System as you're second guessing the speed when you get the gear, but maybe I am reading too much into it?

Hi Chris. Roadcraft advocates overlap between brakes and gearchange in a couple of specific circumstances - downhill towards a bend or other hazards, because otherwise the speed will rebuild while changing gear, and in order to brake later when preparing to turn from a major road to a minor road if required to meet the expectations of following traffic. Use of H'n'T could be considered consistent with the System in these circumstances.

What book are you reading? Is it the John Lyon Porsche driving book from the 80's? If so, those were circumstances in which he demonstrated use of H'n'T on the road.

<Typical member of my local group> H&T is the spawn of the devil and your car will catch fire if you attempt to use it. The flames will act as a target marker for the Roadcraft Police who will hunt you down...</typical member...> . Meanwhile, most of us either follow Andy M's advice and take the gear earlier, in the firm braking, which limits how often you can use H&T on the road, or become as skilled as Pat Rochford, who seems to be able to H&T on even very light brake pressures disgustingly smoothly. When I grow up I want to be Pat...

ScoobyChris wrote:

Octy_Ross wrote:Chris, stop reading the book, go out and try it.. it makes sense and is great fun when you're getting it right!

Interestingly trying it was what was causing me problems as I had been trying to remain systematic and overlapping by coming off the brakes at the same time as the gear blip (speed set before gear) which led to quite a lack of smoothness as I'd lost the firm platform of the brakes being held on. Sounds like I need to bring the change slightly earlier so I can stay on the brakes but still arrive at the correct speed at the hazard.

Thanks folks.

Chris

Let's be honest here, heel and toe is, fundamentally, a competition technique, designed to save time.
Usual caveats about balance, weight transfer for any vehicle and particular conditions.
Simply, in competition, on the brakes or accelerator, so, if you can shorten the time for gearchanging it's to the good.
Much competition is on well known tracks and venues where one is aware of braking points and the nature of the following corner, without the possibility of unseen hazards.
So, it's brakes, hard, gearchange while braking, gear selected, off brakes, immediately on accelerator.
Ok, there's the point at which to apply steering input too.
Not really applicable for public road driving in the main.
Although done in a "lazy" style, it can be used, much as Waremark has previously suggested.
That said, I do occasionally use it, on "challenging", twisty roads with corners with little view through, meaning brake hard up to the corner, get the view out, select appropriate gear, off brakes and accelerate according to the situation.
Anyway to develop the technique it's just, as with all, practise and more practise.
Oh, there's the question of how you take the gearchange too, single declutch or double, I'm assuming revsmatch on either.

Surely there can be nothing wrong with overlapping breaks and gearchanges (whether hell and toe or not) provided its part of your driving plan and not a last-minute decision to keep you on the road 'cause you got it a bit wrong.

That being said, its a handy thing to know for those one or two situations just in case (we all make miscalculations now and again).

The way I see it things like HnT and left foot braking (while not nessessary to be a good, safe driver) just give you more weapons in your arsenal of skills to help you navigate the road safely. It can go in the attache case next to the system =P

So long as its planned in advance, surely its still system-sensitive?

Paul_Black wrote:The way I see it things like HnT and left foot braking (while not nessessary to be a good, safe driver) just give you more weapons in your arsenal of skills to help you navigate the road safely. It can go in the attache case next to the system =P

This could become a very entertaining thread; "Brake Gear overlap" (again), then throw "left foot braking" in


@Paul_Green,
are you talking left foot braking in an automatic, or automated manual gearbox, or a conventional gearbox?

@Ivor,
ah the good old days of Gardner 6LXB's coupled to David Brown 6-speed boxes, you forgot to mention the lack of power steering as well...

Paul_Black wrote:Surely there can be nothing wrong with overlapping breaks and gearchanges [...] provided its part of your driving plan and not a last-minute decision to keep you on the road 'cause you got it a bit wrong.

Sometimes drivers delude themselves into thinking they had a plan but really their use of H&T is mainly a consequence of poor planning, too high an entry speed, and the fact that they are able to use the technique. I'd ask those that habitually use it about the benefits they perceive, other than it being fun.

The consequences are that the driver will normally be braking later and more firmly, and the temptation is then to be braking into the hazard rather than having completed the braking before the hazard, which in turn will result in a potentially tricky transition between braking and acceleration in the hazard.

Gareth wrote:

Paul_Black wrote:Surely there can be nothing wrong with overlapping breaks and gearchanges [...] provided its part of your driving plan and not a last-minute decision to keep you on the road 'cause you got it a bit wrong.

Sometimes drivers delude themselves into thinking they had a plan but really their use of H&T is mainly a consequence of poor planning, too high an entry speed, and the fact that they are able to use the technique. I'd ask those that habitually use it about the benefits they perceive, other than it being fun.

Isn't that enough reason (provided it's having no adverse effect on the outcomes) ?