I discovered - in my late father's papers - a cutting from the Telegraph from, I imagine, the mid 1990s, which I reproduce here. Interesting to see that it refers to a driving style invented in 1936. Written by Paul Ripley:
When I learned to drive, motorists were taught to change down sequentially through the gearbox to lose speed on the approach to hazards. This meant that the driver had to change down through 2 or 3 gears to select the correct one, a technique still practised by millions around the world. Unfortunately it has some disadvantages, namely:
1. Unless you have a 4WD, it means you are effectively braking (via engine compression) with the two driven wheels only. (The foot-brake works on all four wheels.)
2. Changing down through the gears to lose speed can cause unnecessary mechanical wear on a number of engine and transmission components.
3. A following driver may not notice or realise that you are reducing speed, because he expects to see brake lights when a car slows. This means he has less time to react, which may in turn cause problems for vehicles travelling behind him.
4. Changing gear menas you cannot keep both hands on the wheel, which is necessary for control and safety when braking firmly as the vehicle is unstable in this condition.
5. You must be able to correctly match engine speed to equivalent road speed before you select each gear. Clutch operation must be smooth, especially when letting up the clutch onto a 'dead' engine (i.e. at tickover).
These are just some of the reasons why changing down through the gears to slow down the car is no longer recommended (although as discussed last week, it is still useful in some slippery condititons, when braking may reduce tyre grip).
What is taught nowadays is to miss out the 'unnecessary' intermediate gears in most situations. The brakes are applied once, followed by a single gear chagne.
Having been taught the old way, this at first sounded strange to me, but through motivation and practice, I eventually got to grips with the new technique. In fact, it is not really new, having been used extensively by police drivers and other advanced dirving organisations for many, many years. Indeed it appeared in the Roadcraft Police Drivers Manual as early as 1936.
So how is it done? When using the Driving Plan on approach to hazards (for which the sequence is Mirror-Signal-Postion-Speed-Gear), speed should be lost b y means fo a singel braking application or decelartion to achieve an appropriate road speed for entry to the hazard.
Only when the desired speed has been achieved is a single gear change made, selecting thegear to match the chosen road speed and to provide maximum control, balance and flexibility as you negotiate the hazard.
You will find that this requires greater levels of awareness and anticipation (no bad thing). A common error at first is failing to alow enough time and space to complete both the braking application and the gear change.
The secret is to start losing speed much earlier; this not only produces smoother, more controlled deceleration, but allows plenty of time to make an unhurried gear change before you enter the hazard.
It may well be better in certain situations to select a gear slightly earlier when approaching a doubtful traffic situation, such as a busy roundabout. In circumstances such as these, it is important to be flexible when applying the 'one gear change only' rule. As with other dirving 'rules' , sticking rigidly to the text book occasionally brings its own problems. A good driver must be flexible if safety is the prime objective.
|
Nicely written. Thanks for posting that.
WTM
|
|
|
I used to enjoy Paul Ripley's column in the Motoring Telegraph. His views on driving techniques were always tempered by the final paragraph in mapmakers example of his work, which was the need for a flexible approach depending on the situation at any particular time rather than blindly following the prevailing mantra.
Something the DSA would do well to instill in their driving examiners, who can sometimes expect test candidates to deal with a situation in a manner which is highly impractical given the circumstances of the moment.
|
|
I was taught to block change down when I learnt to drive 3 years ago.
|
I accept the general principles articulated here, but ...
Changing down through the gears to lose speed can cause unnecessary mechanical wear on a number of engine and transmission components.
... does this cause any more wear than the process of acceleration?
In addition, many of today's cars are far higher geared than cars of the past (many cars today, especially diesels, do 30+ mph per 1000 rpm in top).
Therefore, applying the brake in top gear to the point where engine speed has been reduced roughly to idling speed will still mean that the car is doing around 30 mph.
Others' views?
Oz (as was)
|
|
The key word is 'unnecessary',you do not have to use the gears to slow down,you have to accelerate if you want to go anywhere.
|
Brake pads are cheaper than gearboxes....... no need to say more.
Ever tried a sustained rev gear change for a situation where you may need poke to get out of it or.
Keep accelerator pedal at its position and change down without altering that position. Engine revs remain up and your ready to go or reduce....
DVD
|
If you hold the accelerator pedal in the same position and dip the clutch, you'll probably find the revs shoot up rather than remain constant.
At idle, a gentle push on my accelerator can take the car to the rev limiter.
|
|
|
This is a technique I was taught to use on my motorbike by a police rider friend of mine. Works a treat.
--
\"Nothing less than 8 cylinders will do\"
|
Of no road use benefit, but repeated anyway; some years ago, I spent a couple of days at a Welsh rally school.
In a MKII Escort RS2000 I was taught that when needing to make a 'handbrake' turn, instead double-de-clutch in to the lower gear required for the corner ahead (without this technique, baulk rings may prevent the down change) then, at the same time as commencing the turn, violently side-step the clutch with low engine revs to cause the rear wheels to momentarily lock, and then apply full power in to the ensuing opposite lock slide.
Sure, it worked, and I've since heard of the same technique being used in 'power sliding' competitions, but against the clock at the end of the weekend, I found conventional (fly-off equipped) handbrake turns to be faster and probably mechanically more sympathetic.
|
In a Hillman Imp the inertia of the engine was so small and the gearbox synchromesh was so strong that you could change down from top straight into bottom at 70 mph. But you daren't let the clutch up whilst still in bottom at 70! (Well, so I was told by a Rootes Group Experimental Dept. test driver.)
--
L\'escargot by name, but not by nature.
|
In a Hillman Imp the inertia of the engine was so small and the gearbox synchromesh was so strong that you could change down from top straight into bottom at 70 mph. But you daren't let the clutch up whilst still in bottom at 70! (Well, so I was told by a Rootes Group Experimental Dept. test driver.) -- L\'escargot by name, but not by nature.
>>
This is a rare example where too much design margin can lead to a potential problem. Some components are better if they are designed to fail at a known load (or speed) above their maximum design rating, in order to protect other more expensive parts, or to retain safe control of the vehicle.
Clutches which are better designed will 'centrifuge' the lining material off if they are spun at too high a speed. (would the driven plate be doing approximately 20,000 rpm at this point?) So, if you were to let your clutch up while doing 70 in first, nothing would happen, you would lose drive, and have to pay for a new clutch rather than a new engine.
number_cruncher
|
|
Better still, use a proper slipper clutch mechanism as is used on many racing motorcycles - and increasingly, full-on road going sports bikes, too; these slip when a threshold reverse torque load is exceeded, and are designed to help such as with downchanging under hard braking when the rear wheel has little grip and would otherwise lock during lower gear engagement.
|
|
|
|
has some disadvantages, namely: 1. Unless you have a 4WD, it means you are effectively braking (via engine compression) with the two driven wheels only. (The foot-brake works on all four wheels.) 2. Changing down through the gears to lose speed can cause unnecessary mechanical wear on a number of engine and transmission components. 3. A following driver may not notice or realise that you are reducing speed, because he expects to see brake lights when a car slows. This means he has less time to react, which may in turn cause problems for vehicles travelling behind him. 4. Changing gear menas you cannot keep both hands on the wheel, which is necessary for control and safety when braking firmly as the vehicle is unstable in this condition. 5. You must be able to correctly match engine speed to equivalent road speed before you select each gear. Clutch operation must be smooth, especially when letting up the clutch onto a 'dead' engine (i.e. at tickover).
Regardless of my view on the overall subject, these 'disadvantages' seem quite biased. They appear to assume that someone is purely using the gears to slow down, no braking at all. Is this likely? I would certainly agree that was not a good way to drive.
If someone used the brakes and the gears, that would straight away mean that numbers 1 and 3 are not applicable. Call me arrogant if you like, but I also don't believe that my driving is so on the knife-edge that 4 makes a difference, and I seem to be able to cope with 5 without any problems at all.
So we're left with 2, which is also lessened by the brakes+gears method, to a point where I believe it is pretty much irrelevant.
So what's the reason not to do this again?
|
Bazza - there is no assumption that someone is purely using the gears to slow down. That is an explicit statement, near the top - "When I learned to drive, motorists were taught to change down sequentially through the gearbox to lose speed on the approach to hazards." That's how I used to do it - with minimal use of brakes!
Regarding your point on item 4, you will be right 99.9% of the time, but there may be an occasion when firm braking is required while changing gear due to "the unexpected", and the point is therefore valid. A lot of advanced techniques are really promoting a driving style which mitigates the risk if "the unexpected" were to happen.
|
That is an explicit statement, near the top - "When I learned to drive, motorists were taught to change down sequentially through the gearbox to lose speed on the approach to hazards." That's how I used to do it - with minimal use of brakes!
So it was actually taught to not use the brakes at all? In that case I withdraw my complaint. I was taught to use the gears and brakes in harmony, while the new teaching appears to be to use the brakes with no gears at all. I had assumed that the people referring to using gears were referring to what I was taught, not a third way.
I can't see any benefits at all to only using the gears. The only situation I can think of is where you see a hazard, or reason to halt, a long way ahead, and just let the car naturally slow. In that case too I would probably go through the gears, but I wouldn't be using them to slow, I'd just be matching them to the speed I was doing, after I had attained that speed (if you see what I mean)
|
I was taught to drive the old-fashioned way, ie using gears to slow - but that was nearly 40 years ago.
In 1982 I bought my first automatic.
Now, I just can't imagine how this 'work the clutch and change gear by yourself every few seconds' ever caught on...
|
|
|
I can't see any benefits at all to only using the gears.
You would use gears (along with some form of retarding device) in a heavy vehicle on a long decent to avoid overheating the brakes and causing brake fade.
WTM
|
>> I can't see any benefits at all to only using the >> gears. You would use gears (along with some form of retarding device) in a heavy vehicle on a long decent to avoid overheating the brakes and causing brake fade. WTM
Ah yes, but again, that's not using the gears to actually slow the vehicle, just to maintain that speed.
I do that already on steep hills, in a car. Why sit in 3rd with the brakes slightly on all the way down a hill, when you can sit comfortably in 2nd with the car keeping itself at a steady speed?
|
|
|
|
"while the new teaching appears to be to use the brakes with no gears at all"
Hi Bazza,
Not such a new technique - Roadcraft has been around for quite a few decades ;-)
Police drivers I have worked with via RoADA and IAM and my forays with DSA, tell stories of comparatively poor braking systems in the cars being driven when roadcraft was originally "conceived" - 1950 something if memory serves. The bottom line is that today, brakes do their job very well and you can rely on them to their job!
Gears are not designed to slow the vehicle as their primary function - but we all know there are times when this may be desirable.
As for gears to slow technique, every downward change involves coasting when the car is doing anything but braking. This is not an issue with the brakes of course, and engine braking will still assist to some degree :-)
|
Not such a new technique - Roadcraft has been around for quite a few decades ;-)
But has that been Roadcraft's advice for all their life? I had gained the impression that it was not.
Anyway, I'm only calling it 'new' to differentiate from the 'old' technique.
|
In terms of the "Blue book" yes, speed THEN gear has been advocated.....
The new roadcraft has blurred the system beautifully - "One size fits all" springs to mind, but that would be a whole new thread ;-)
Regards.
|
Off topic but I can't be bothered to find the proper thread - new study from Leeds Uni has this interesting snippet:
" ?For example, we?ve already discovered that in modern vehicles it?s far less polluting to accelerate up through the gears in a structured but swift way than driving very cautiously or aggressively.?
The car is also being used in EU, department for transport and EPSRC-funded projects, including a study of how in-car information systems distract drivers. We?re no longer allowed to use hand-held mobile phones while driving, but a current project is investigating how GPS, route guidance and voice controlled email systems affect driving performance."
Full article:
reporter.leeds.ac.uk/507/s2.htm
|
|
|
for grnicol
Now would that be an Imperial, Metric of AF thread?
DAW
|
Now would that be an Imperial, Metric of AF thread?
DAW
Ermmmmm, how about "The Latest Roadcraft - it is an improvement?" thread ;-)
No, best not go there.
|
|
|
|
|
>BaazaBear wrote: But has that been Roadcraft's advice for all their life?
Well, that was the imho interesting thing about Ripley's original article I quoted above in which he wrote: 'Indeed it appeared in the Roadcraft Police Drivers Manual as early as 1936.'
That's before the abdication.
|
|
|
|
|
|
|
