How can "Braking" two wheels give you better control then braking with all 4!!!!
And which two do you think have the most braking influence?
Discs front, drums rear on most cars I see day to day except BMW's etc.
I personally don't mean it from a control point of view, just that in my opinion, balancing the engine speed with the road speed and dropping down a gear is far more involving than simply going for the brakes. To my mind you need to be able to read the road properly to do it well.
>>With modern cars and aidssuch as ABS there is no reason to use the gears to slow down, you do not have full control using this method.
Well, I've never lost control while using engine braking going down a hill, or approaching a roundabout...
>>If you drop a cog and your engine speed isnear the red line
What sort of pratt does that?
At the end of day just look at what the components are called:- BRAKES = Braking Transmission = Transmit drive to the wheels Simple aint it ;o)
But if you can manage to engine break without ruining your clutch, and there fore save brake pads etc, whats the harm? All you're doing is using engine compression.
|
I think the conclusion of this thread is that there is no right or wrong method. It's a matter of preference. Personally I prefer to let the brakes do the braking, unless I'm on snow or ice.
|
>Nobody here has reported any problems with using gears to slow.
Who would know? Who is to say whether that gearbox or clutch failure was caused by poor design or engine braking. (Ask Aprilia's Renault friend if he uses the gears to slow.) In the absence of a double blind test under laboratory conditions, we're not going to find out the answer to this anymore than we're going to find out if Optimax is any good (in a car that doesn't need it).
Actually, a friend's Series II Landrover's gearbox exploded whilst attempting to slow the Landrover using gears.
Engines, gearboxes & clutches DO wear out. And engine braking will cause this wearing out to be accelerated. The more times the little thingies under the bonnet go round, the more worn they will become - it's a fact.
There is no doubt (that for everybody except Superman) that when slowing down better control of a car is obtained by having two hands on the steering wheel than one. (Oh, silly me, I bet nobody bothers with two). Removing one hand to put it on the gear stick will reduce the level of control.
>If it rhymes it must be right.
That 'silly' rhyme is used by driving instructors everywhere, because it is generally agreed by those who teach driving that gears are for slow and brakes are for go. (Look, that still rhymes.) And the rhyme is a handy way of drumming it into gold-hooped-earing bedecked, gum-chewing teenagers.
|
"And the rhyme is a handy way of drumming it into gold-hooped-earing bedecked, gum-chewing teenagers."
What a lovely picture.
|
|
|
That 'silly' rhyme is used by driving instructors everywhere, because it is generally agreed by those who teach driving that gears are for slow and brakes are for go. (Look, that still rhymes.) And the rhyme is a handy way of drumming it into gold-hooped-earing bedecked, gum-chewing teenagers.
To be honest, people keep quoting that rhyme as proof that this is the right way to drive.
It is used, as you say, by driving instructors, as a memory aid for new and inexperienced drivers - it wouldn't be the only thing they tell their charges that is NOT the best way to drive, but is a very good way for a newbie to drive, until they become proficient enough to use more advanced techniques. Such as using all the elements of the car, brakes and engine, together - in harmony.
As I see it, the over-riding reason for that technique is to make it as simple as possible, I reckon the majority of people on here are capable of driving successfully without requiring such simplicity.
|
To be honest, people keep quoting that rhyme as proof that this is the right way to drive.
Ex boss used to quote YCDBSOYA (or something similar) "You Cannot Do Business Sitting On Your Ar$e", pointed out to him that it can also mean "You CAN Do Business Sitting On Your Ar$e".
Same can be said for the numerous motoring related acronyms, POWER etc etc.
|
|
|
I took my driving course in the RAF around South Wales in a long wheel base Landrover. Then took my test in a Moggie Estate. Was taught not only to change down, but also to double de-clutch too between 3rd and 2nd. Mind you, you had to then!
I still sometimes find myself doing it. And you know what? I don't care.
Sometimes, I even double de-clutch going up the gears too!
Learned to drive over 30 years ago and have ALWAYS thought that changing down prior to bends, roundabouts, hazards, going down steep hills gives me much more control.
My Mrs takes turnings in 5th gear and I hate it when I hear the engine pinking and struggling, then the snap of my neck as she changes from 5th to 2nd to get some life into it again.
|
|
|
When I learnt to drive about 8 years ago I asked my instructor about engine braking and he seemed to think it was okay. Later on the IAM taught me that it is better to use the brakes to brake and I now agree as I think I have more control, and wear the gears less.
The IAM use a simple 5 phase system: Information, Position, Speed, Gear and Acceleration. The idea is that on approaching a hazard, you asses the road ahead, adjust your speed to suit (by braking), then change down to the suitable gear, and finally when you clear the hazard, accelerate away. When you accelerate away there's no need to climb through the gears, 3rd to 5th is fine. Part of the reason for this method is to avoid unnecessary gear changes, so that both hands are on the steering wheel most of the time when approaching and negotiating the hazard, and your attention is thus on the hazard, and not the gears. I was taught to use a low gear near the hazard to provide plenty of acceleration if need be e.g. if a car comes straight at me I can quickly move out of the way without needing to change down. Hence I might often be in a lower gear than some other people when going round a roundabout. I probably use more fuel like this, but I believe that it is safer. Anyway, the anticipation and early braking taught by the IAM should help improve fuel consumption overall. I reckon that I am a better driver as a result of IAM lessons.
I assume that police drivers are taught this method to keep their attention on the road ahead, and their hands on the steering wheel rather than saving wear on gears. But then again, they do drive in a more extreme manner and hence require higher standards than most of us.
Leif
|
|
|
|
And engine braking will cause this wearing out to be accelerated.>>
There is a difference between using the engine to slow down gradually than by going down to the lower gears (plus increased revs to match them) for a more powerful effect - the former is much kinder on the mechanicals in most situations because you are not having to then build up momentum from rest or slow speeds. It also uses less fuel.
But the situation will be slightly different every time and that is why anticipation is so important.
- - - - - - - - - - - - - - - - - - - - -
What\'s for you won\'t pass you by
|
|
|
|
|
|
I use vehicles everyday that have an "Engine Brake", it works by backing up the exhaust gasses and slowing the engine down that way, I have also used trucks that have retarders fitted, this is a 3 position lever on the dash that you pull down to act as a braking force usually on the prop shaft (I Believe), these devices are designed for the purpose and the vehicles are designed to use them. That having been said, both type's will only work on the drive axles, as a result you would not use either in icy/snowy conditions and I very rarly use them in the wet as that can also be a bit too slippy. I don't beleive modern car drive-trains are really designed for this type of use.
|
Still think were taking black and white positions on a range of grey. Let me give you a for instance where I might use either technique. At the start I?m driving a 2.0 litre turbo diesel with a 5 speed manual box at NSL in top gear on a fast single carriageway A road and approaching a village in which I wish to turn right into a side lane.
?Approaching village and fifty limit, I?ll ease off the gas now and let the speed decay. Passing the limit I?m at fifty and running 1500 rpm so drop it into 4 Three hundred metres on I?m approaching a junction, with two pubs and a garage. Fifty is pushing it some and I let the speed fall back to 40, 1800 rpm and falling so drop to third. I?m now coming up to my turn, which has a deceleration lane/refuge. Mirror, there?s nobody behind to inconvenience, signal etc and enter refuge, throttle?s off and speed decaying smartly towards 25. Take second gear, revs peak at 2500 and fall back further, as I spot a nice gap in the southbound traffic I?m rolling towards end of refuge at 10/15mph, blip throttle and I?m safely in the side road. If I need to stop I can catch it with a dab of brake and drop into first?
I was being close followed and pressed at the point where I felt 40 was fast enough I might enter the deceleration refuge early, using the broken line/cross hatched ?pre refuge? area and then slow with firm braking and a block change to second.
Horses for courses, and I don't think ther's anything there that differs greatly from what the IAM told Leif. I'm observing all the way and matching my speed to hazards but keeping in the gear where I have either power or engine retardation in hand at all times.
|
|
Not arguing with what your saying. But the difference is "Letting your speed decay", that is not really engine braking. Engine braking is dropping it a cog or 2 and using the high revs/compression of the engine to slow the car more rapidly.
|
Not arguing with what your saying. But the difference is "Letting your speed decay", that is not really engine braking. Engine braking is dropping it a cog or 2 and using the high revs/compression of the engine to slow the car more rapidly.
I have to agree. Engine braking is induced by changing to a gear that is far too low for the speed, and hence the engine revs drop dramatically. Also Bromptonaut seems to be describing smooth driving on approach of numerous hazards each requiring a lower speed and hence lower gear rather than seeing one distant hazard and slowing from 5th to 4th to 3rd to 2nd.
The IAM observer did seem to slow and accelerate more rapidly than me, as I tended to prefer to shed speed more naturally. Obviously that approach is more suited to performance driving where haste is required.
Leif
|
I have to agree. Engine braking is induced by changing to a gear that is far too low for the speed, and hence the engine revs drop dramatically.
Think I've been arguing for no reason, as I don't change so the engine ends up screaming, just to the same revs I'd normally change at when the torque runs out (8v so low down)
|
If using the gears to slow only works on two wheels - and braking works on four wheels, what about me in my Scooby?
--
Espada III - well if you have a family and need a Lamborghini, what else do you drive?
|
I knew someone would bring that up!!!!! Sooooooo predictable!!!!!
I guess it would work on all four, still not as contrable imho.
|
|
|
|
Not arguing with what your saying. But the difference is "Letting your speed decay", that is not really engine braking. Engine braking is dropping it a cog or 2 and using the high revs/compression of the engine to slow the car more rapidly.
I think this is the crux of the matter, and the cause of this discussion. I have been arguing in favour of using the engine as well as the brakes, but I certainly don't do what you describe there. I very much doubt that the other proponents of engine braking on here do either.
Mind you, I would suggest that that is only YOUR definition of engine braking. I would still describe what I do as engine braking, just not as extreme as what you consider the term to describe.
|
SO - is the question really
"how many revs is too many revs?"
|
SO - is the question really "how many revs is too many revs?"
When the pistons start tapping the valves because the springs cant pull them out of the way in time is a good place to start, but you could always settle for the con rod poking its way out of the block to say hello.
WTM
|
>> SO - is the question really >> >> "how many revs is too many revs?" >> When the pistons start tapping the valves because the springs cant pull them out of the way in time is a good place to start, but you could always settle for the con rod poking its way out of the block to say hello. WTM
:^D
I wouldn't soley engine brake at anything more than 3000 - 3500 on my current car. On the 16v obviously I did a little bit higher.
|
When I took my test I was told by my instructor that your should do the heavy braking early and ease off the pedal, essentially making braking a two stage process. I was also advised to come down through the gears, at first this was 5, 4, 3, 2 handbrake & neutral, then progressed to block changes from 5th to 3rd or 4th to 2nd.
Having undergone intensive driver training at a rally school in both rear wheel drive and four wheel drive, they hammer it into you that braking is a three phase process. Gently bringing the pads onto the disk, increasing the pressure to take the speed off then a controlled release and back on the power, whith an overarching emphasis on smoothness.
Interestingly the technique taught is irrespective of the number of driven wheels or which wheels are doing the driving.
I have become used to slowing down in this way, but for road use, combine it with coming down through the box.
As the rear brakes only do about 20 - 30% of the braking surely it is is better to offer some assistance to the front wheels by using the engine braking effect.
Leon
|
As the rear brakes only do about 20 - 30% of the braking surely it is is better to offer some assistance to the front wheels by using the engine braking effect.
Whatever you do, deceleration is limited by the capability of the wheels to remain rotating and not locking. Modern brakes are quite capable of going beyond this point, and therefore do not need supplementing by engine braking.
--
L\'escargot by name, but not by nature.
|
>> As the rear brakes only do about 20 - 30% of >> the braking surely it is is better to offer some assistance >> to the front wheels by using the engine braking effect. >> Whatever you do, deceleration is limited by the capability of the wheels to remain rotating and not locking. Modern brakes are quite capable of going beyond this point, and therefore do not need supplementing by engine braking.
But if you are in the correct gear then using the engine in this way will make the wheels LESS likely to lock.
If you're staying in 5th for the whole braking procedure and only changing when you come to pull away again then you're either going to have to push the clutch in early, or run the engine down to VERY low revs, at which point it not as effective at stoppiong the wheels from locking.
|
At the top of a steep hill near where I live there is a sign which reads 'ENGAGE LOW GEAR NOW'.
I wonder why? :o)
|
At the top of a steep hill near where I live there is a sign which reads 'ENGAGE LOW GEAR NOW'. I wonder why? :o)
It's to limit the speed, not to produce a continuing reduction.
--
L\'escargot by name, but not by nature.
|
>> >> At the top of a steep hill near where I live >> there is a sign which reads 'ENGAGE LOW GEAR NOW'. >> >> I wonder why? :o) >> >> It's to limit the speed, not to produce a continuing reduction. --
It's still producing a braking force, in exactly the same manner. It's just that in this case the braking force is counteracted by acceleration due to gravity.
|
>> >> >> >> At the top of a steep hill near where I >> live >> >> there is a sign which reads 'ENGAGE LOW GEAR NOW'. >> >> >> >> I wonder why? :o) >> >> >> >> >> >> It's to limit the speed, not to produce a continuing reduction. >> -- It's still producing a braking force, in exactly the same manner. It's just that in this case the braking force is counteracted by acceleration due to gravity.
I suspect that engaging a low gear at high speed where the revs are ill matched puts far more strain on the box than using a low gear with matched revs for a hill descent. In addition, even if the latter does lead to more wear than using a high gear, is not safety the overriding factor?
Leif
|
I suspect that engaging a low gear at high speed where the revs are ill matched puts far more strain on the box than using a low gear with matched revs for a hill descent.
But if you read this thread, no-one on here does the former. Everyone who is talking about using the engine to regulate speed in both directions, talks about doing the latter.
In addition, even if the latter does lead to more wear than using a high gear, is not safety the overriding factor?
Precisely, therefore being in the right gear at the right time and being able to react that much quicker is the most important thing to me.
|
Bazzabear: Some people are talking about engine braking which presumably strains and wears the gear train, and some about simply progressively changing down through the gears. I feel that the IAM method improves safety, and is easier, and it is based on being in the optimim gear, but that's my choice. Anyway, I can't reach a conclusion without seeing how you drive in a given situation as words are not enough.
Leif
|
Anyway, I can't reach a conclusion without seeing how you drive in a given situation as words are not enough.
If anyone is up for a lift down Marlow Hill in High Wycombe on my way home tonight then let me know!
|
I once knew someone who changed down to first gear by mistake on a motorway and wrecked their engine or gearbox or both.
Cheers, SS
|
What I can't understand are the signs at the BOTTOM of a hill that say "Select low gear now."
How do they know what you are driving?
|
I once knew someone who changed down to first gear by mistake on a motorway and wrecked their engine or gearbox or both. Cheers, SS
I can't get my car into first at 20mph never mind 70, someone that depressingly stupid was going to wreck their car one way or another.
|
I am one of the committed 'change down to slow down' brigade.
My BMW 320d does 30 mph per 1000 revs in 5th and I just wonder how badly it (or any other modern diesel) would protest if I braked down to 5-10 mph before changing down.
I'm not prepared to find out.
Oz (as was)
|
|
Anyone seen the sign coming out of Calais on the motorway towards Boulogne? "Use your engine braking" Instruction or prophesy?
|
"Anyone seen the sign coming out of Calais on the motorway towards Boulogne? "Use your engine braking" Instruction or prophesy?"
Yes ( not far from a similar sign on the N1 which says "Dangerous Declivity - Use your engine braking") there are many on French (and German) motorways which seem to have much steeper and longer hills than ours. I suspect that these are largely aimed at (British/Dutch??) caravans that may be overloaded and are racing south to the sun. In such conditions it is far too easy for caravans to become unstable and it is, in these situations far better to engage 4th or 3rd gear which will keep you at (say) 60 mph rather than using the brakes for a couple of miles ( with the risk of fade?).
On German motorways and in the Alps it is quite common to come up behind trucks on very long hills without brakelights on but only doing about 20 mph - I presume in a low gear. Having said that, I also followed a logging truck downhill in the Black Forest where he kept locking his brakes and there were clouds of smoke coming from both tyres and brakes which was not very reassuring. In a coach once on the Grossglockner Pass in Austria our driver had to stop in a lay-by for half an hour because, despite using his Telmar transmission brake and the exhaust brake, his brakes were also smoking and becoming rather ineffective! In each case I suppose the gears could be or were being used or not in order to "limit speed" rather than in order to "slow down". Whether it also applies to solo modern cars is another matter.
Sorry for long post!
|
>>My BMW 320d does 30 mph...
I know they come without indicators, but had no idea that BMW had done away with the clutch as well!
|
I know they come without indicators, but had no idea that BMW >> had done away with the clutch as well!
H'm. Hints at a strange, 2-legged approach to slowing down ... or coasting ... or something.
I'll stick with the idea of arriving in the gear in which I expect to drive on.
Oz (as was)
|
|
|
|
|
|
