I double-de-clutch when changeing down, ****ed my driving instructor off though. Told me not to do it

When I'm going about making serious progress (or try to!), I don't go down "through" the gears, but for example stick it in third, but keep the clutch out (so effectively illegally driving whilst idling), then drop the clutch when at an adequate speed so the engine revs are say around 2000, ready to push forward after the apex of the bend / roundabout.

It's probably naughty, but when you're braking so hard, I don't see the point because as soon as you get in a gear, you have to change.

If driving casually, I suppose I could do it, but I'm just too lazy. I only use gears / engine brake if I feel I need it, otherwise coast to save on fuel

Tfboy, AIUI coasting with the clutch out but a gear selected is not illegal, but is bad practice. I've heard of cases where people got their revs wrong, and snapped the crank when they had to drop the clutch in a hurry.

Another point worth noting is that freewheeling actually uses more fuel rather than less as the engine needs the fuelling to keep it 'ticking over', unlike the situation where you are in-gear and the wheels turning causes the engine to get turned (which pretty much shuts off the fuel injection process)

I double-de-clutch when changeing down, ****ed my driving instructor off though. Told me not to do it

I'll some times do that, but generally I change down as I slow but blip the throttle to avoid clutch wear. Brakes are for slowing you, not clutches.

Thats to pass your test at granny speeds chum - changing down is best....

Funny the chaps and chapesses in the advanced driving community and HPC seem to disagree with you and they definitely aren't doing granny speeds

Chris

Funny the chaps and chapesses in the advanced driving community and HPC seem to disagree with you and they definitely aren't doing granny speeds

Chris

ADvanced driving courses are only good for one thing - teaching observation and preparedness the car controll side of it is crap designed only to slow people down - not to get them through the corner safely at high speed.

Engine braking is discouraged for the roundy boys when track driving as there you can plan everything long in advance and have minimal worries being on nice stable tarmac with nice fast corners.

However get into rallying and ALL the top drivers will use engine braking substantially, not one good rally driver would apply the AIM \ DOT test car control principles like shuffling the wheel through your hands etc or about braking in 5th.

When things get unpredictable when things may catch you off guard you are far better off being in the right gear for road speed at all times. It also leads naturally to smoother driving in every day traffic because if the queue you were slowing down for ahead suddenly starts moving you're there in the right gear ready to accelerate or maintain speed. no changeing from 5th to 2nd before you are ready to move again.

What happens when you are braking hardish for a set of traffic lights in 5th gear and the car in front of you suddenly pulls off left without indicating coming to a virtual standstill in front of you as they turn unexpectedly into a side road (whats the betting its a BMW ). Push the brakes harder? and lock up or push the brakes harder let the abs kick in and extend your stopping distance by 30% whereas if you are slowing down on the gears more you have far more brake travel left to use before you hit such problems.

Okay another scenario you're driving at night come round a corner at 60 into some traffic doing about 40 up hill to a crest suddenly the cars that were doing 40 all stop you are already on the brakes slowing down to 40 in 5th what do you do press harder? whereas if you are slowing down on engine braking again you have simply got more options open to you.

Engine braking is SAFER to use it gives less chance of lock up. If the roads were an empty dry race track then certainly by all means the AIM principles would be fine, but AIM car control principles dont help when things go wrong, and for all the observation and care inteh world things CAN and DO go wrong. When something goes wrong Id rather be in the right gear to react with plent of options open to me as to how to handle the situation rather than being virtually coasting in 5th gear withmy foot on the brakes already.

Using your brakes is one of the most dangerous parts of driving, lockups under braking and abs cutting in extending your stopping distances are a major cause of many accidents. One of the hardest things to learn when learning to competition drive is learning when to stay off the brakes, rally drivers WOULDNT be able to go the way they do on horrendous terrain if they braked in 5th, Theres times in rallying when you CAN NOT use your brakes without encountering the scenery and its not uncommon in those situations to exclusively use engine braking to scrub speed without risking lock up in dicey territory

Take a look at this for a stunning display of exceptional driving:-

Patrick Snyers - BMW M3 e30 Manx International - Google Video

Listen to the engine sound hes changeing gears and using engine braking and coming out of corners etc in the right gear, now imagine him trying to hold the same pace exclusively using brakes and changeing down once he was in gear and using AIM principles of wheel handling He would be off the road. The very last few seconds you can see his brake lights throught he last few corners and realise hes virtually entirely using engine braking!

Of course you might say that he should be driving slower in the first place - that maybe so but at ALL speeds you are taking your car further from an accident by applying these techniques than by coasting braking in 5th gear. You are placing less strain on those poor rubber contact patches with the road.

As for costs of gearboxes over brake pads, I havent blown up a gearbox in 10 years of rallying using engine braking. I know some people manage to kill gearboxes for a passtime, but I would guess thats more down to clutchless gearhanges and general abusive gearchangeing, If you can feed the power correctly and cushion the shock then you wont be causing ANY major wear and tear. And my front pads cost £90 a set for mintex racing ones, gearboxes I can pick up for £70 second hand...... Ive got about 4 of them on the shelf from cars Ive broken for spares.

Pretty much sums it all up

No no no! Brakes are for slow, gears are to go

Chris

i just makes no sense to change down when slowing

i just makes no sense to change down when slowing

You go tell Michael Shumacher hes been an idiot for using engine braking then

F1 cars have some of the best brakes in the world - yet the drivers still use engine braking constantly. Perhaps they are all idiots who need to take an IAM test? Perhaps they need to be taught by their local bobby?

Who would I feel safer sat beside in a high speed situation on the public road? One of the worlds top competition drivers or the local police driver? If my life depended on their pace and getting to me safely who would I rather have driving? No doubt in my mind on that one. Despite the idiot racing drivers using engine braking changeing down through the gears as they slow down. also another shocker - some of them gear and steer at the same time

Its all well and good saying its good because thats how racing drivers do it but 1) you're not a racing driver and 2) you're on the road not on a track.

First of all I AM a competition driver thank you very much, I have led a national championship before. I currently own and run 2 rally cars and am hoping to start a 3rd one soon.

Secondly the very same physics that make engine braking safer on rallying and tarmac still make cars safer on the road the physics of where and amounts of braking forces applied and the effects they have on the car are still the same. Also watch the snidjer video - that sure looks like road to me!

Its safer its more controlled plain and simple, braking without changeing down through the gears is far too close to coasting.

So being a "competition driver" enables you to break the laws of physics then? No matter where you derive the braking energy from, there's a limit to how much the tyres can take before they slide.

Nowt about braking the laws of physics, as you say tyres only have a finite grip.

The point being made is that BGOL is acceptable in certain circumstances, even under IAM/RoSPA guidelines.

In "fast" motoring, be it road, track or stage, Changing gear whilst braking is faster. It may be less stable, however it allows snap acceleration without the gear change pause.

As to whether it should be done on road in everyday driving, my answer would be no on the whole but yes under the correct circumstances even when not pressing on.

Do I do it? Depends on circumstances.

It allows me to use the laws of physics differently and to apply forces differently. Do you think that your style of driving would get you through a track safely at the same speeds as a wrc driver in the same car? surely the laws of physics are the same?

Of course they are, now how much do you know of the laws of physics as they apply to tyres and braking?

Engine braking applies the slowing forces very differently to the very harsh braking of normaly brakes, engine braking will not lock up your wheels on tarmac! Why because the engine turns it doesnt lock - pad positions are fixed they snatch and grab and attempt to stop a car, engine braking doesnt snatch it doesnt grab it applies an entirely different force upon the tyres in an entirely different manner.

Im sure you are aware that hitting a nail with a hammer has a far bigger impact than resting the same hammer on the same nail. The engine gives far more elasticity to the braking effect. It adds an additional braking force without adding more "snatch" or shock to the system. Its shock force that causes the problems with braking not the amount of pressure applied! Just like the difference between swing the hammer and resting the hammer.

Do I do it? Depends on circumstances.

That right there is one of the keys to successfull driving road and competion, its being able to adapt to the circumstances not following hard and fast rules about what to do where.

Every corner every obstacle is unique and slight variations in style and approach are what make all the difference the laws of physics acting on a car are VERY complex and small changes can have a big impact.

Being able to tailor you actions to every circumstance is essential - you dont hang on the wheel and brakes and hope for the best and make it or not.

engine braking will not lock up your wheels on tarmac!

Not true I'm afraid. Change down with no finesse, no rev matching, just dump clutch into a gear one or two lower than the one you are in and the wheels will lock with the shock. Seen it done many a time. Particularly bad on gravelk if you ain't expecting it, if you are it can be used to advantage....

That right there is one of the keys to successfull driving road and competion, its being able to adapt to the circumstances not following hard and fast rules about what to do where.

Every corner every obstacle is unique and slight variations in style and approach are what make all the difference the laws of physics acting on a car are VERY complex and small changes can have a big impact.

Being able to tailor you actions to every circumstance is essential - you dont hang on the wheel and brakes and hope for the best and make it or not.

I agree, adaptability is one of the keys to successful driving. Learning something by rote is not. There will always be situations which can sucker you into going down a certain behaviour pattern. Think a forest stage, an unknown road; you think the road is going right, you position for it, you select the speed you think is appropriate and the road then goes left - you are in the wrong place at the wrong speed.

The other thing being missed is "feel". It's the do it by rote thing again. Much better to listen to the car, speak its language and avoid undue stresses on it. It's like asking your body to bend into a different shape or extend your leg whilst standing on the other one.

On gravel where grip is very dicey certainly, but on tarmac just engine braking wont, the same cannot be said of normal brakes!

If you are attempting to turn then it CAN push you over the edge But lets face it if you are on the limit cornering anyway ANY force can chuck you off the road. Theres times in a straight line on gravel when backing off the throttle at all will catapault you off the track But braking in that situation would make a far bigger mess! But gravel is a very different beast to tarmac.

Engine braking by itself on tarmac Ive never managed to lock up wheels. I have on occaision missed gears and over revved an engine badly on a few occasisions, but its never ever locked me up on tarmac.

Maybe its possible with some engines that have huge compression ratios or something? The only time IVe had an engine lock up wheels on tarmac was an engine that siezed. That was kind of fun :(.

I've had the last one, sort of, at about 95-100 :( OSF driveshaft siezed and locked the OSF. Spat me off big time. Nearly managed to control it but hey ho, it's only metal

I agree, adaptability is one of the keys to successful driving. Learning something by rote is not. There will always be situations which can sucker you into going down a certain behaviour pattern. Think a forest stage, an unknown road; you think the road is going right, you position for it, you select the speed you think is appropriate and the road then goes left - you are in the wrong place at the wrong speed.

The other thing being missed is "feel". It's the do it by rote thing again. Much better to listen to the car, speak its language and avoid undue stresses on it. It's like asking your body to bend into a different shape or extend your leg whilst standing on the other one.

I agree with that ENTIRELY. Feel and adaptability are ABSOLUTELY vital, a knowledge of what you can do to effect a car in different situations helps you to select what feels right at that time.

Ive taken some fairly unorthodox approches to some situations because I knew at the time that the physics would work. The physics of what a tyre can take ata ny given time may be fixed but theres so many different variations of what you can make your tyres do at any time.

As for thinking the road goes right when it goes left - I remember well my navigator making the wrong call one time

I will often say the fastest way to stop a car is to put it sideways, but that doesnt mean I use that idea every time I want to stop - or even any appreciable percentage of the number of times I stop. Equally people may say dont brake and steer as a hard and fast rule, which of course might be good advice, but I left foot brake and that I consider safe, but I dont left foot brake every corner, and some times I left foot brake sometimes I scandinavian flick sometimes I slow down and hand brake, its all feel, and theres so many different ways to change the physics of whats happened to your car.

But when it comes changeing down through your gears I argue strongly against it being pointless or a bad idea, but it doesnt mean I apply it every time hard and fast.

Another point worth noting is that freewheeling actually uses more fuel rather than less as the engine needs the fuelling to keep it 'ticking over', unlike the situation where you are in-gear and the wheels turning causes the engine to get turned (which pretty much shuts off the fuel injection process)

But if you are coasting down hill in neutral you don't have engine brakeing slowing your car down, do will actually gain speed and therfore negate any losses from fueling to keep the engine at tickover.

I tried this theory out on a nice long downhill (on a private road) and the car was reporting much higher MPG figures from the coast when compared to the leave it in top and go down the hill.

Brake and steer? Heretic :grumpy:

Sometimes it i good to do both as you change the attitude and balance of the car to your advantage. Use trail braking quite a bit as it is a nice way to balance the car or to unbalance it as the situation dictates.

Quite a lot of people just get it wrong and either spin or roll.

No substitue for experience I guess.

Did your co-driver used to nav for me? Mine sent me the wrong way same as yours did - through a dry stone wall at about 85

After spending a day in the company of God yesterday, not once did he use engine braking on either the road or the track. Maybe it's because the diesel has very little in the way of engine braking, or maybe it's cos he was trying to wear my pads out for me

Either way, he is one of the fastest road drivers I've had the pleasure of going out with (the stuff he was overtaking in my crappy car was phenominal! ) and what he doesn't know/can't do control wise ain't worth knowing

Highly recommended!

Chris

Brake and steer? Heretic :grumpy:

Sometimes it i good to do both as you change the attitude and balance of the car to your advantage. Use trail braking quite a bit as it is a nice way to balance the car or to unbalance it as the situation dictates.

Quite a lot of people just get it wrong and either spin or roll.

No substitue for experience I guess.

Did your co-driver used to nav for me? Mine sent me the wrong way same as yours did - through a dry stone wall at about 85

Yep would agree with that entirely. Heck on the road in good conditions at sensible speed I wont even rule out plain slowing down braking whilst steering round a corner, if it feels as if its 100% safe to do so and as if theres loads of margin for error to spare if something unexpected did happen then I ve got no problems with it, just a gentle scrubbing of speed even when cornering can be absolutely fine. do it wrong and it can be deadly.

Experience? is that measure in bent panels? , Ive certainly accumulated a fair few of them. Nearly considered as service items

As for navs well he does get around a bit generally hes good, but heck anyone can make mistakes and I make as many as anyone so I dont complain, in that situation - through a brown trouser moment I managed to keep things together, ONLY because it was on gravel I spotted things in time to correct and I could swing things around a lot to scrub speed and change direction. If that was on tarmac that would have been a VERY nasty mess. It slowed me down through a good few miles as well "6 left...", "are you sure?"

That said I have remodelled car panels even when hes called things right I cant claim perfection unfortunately, but I dont think theres been many rally drivers out there who havent misjudged at some point. and even less who would claim they follow a set of rules for how they approach every obstacle and corner and that everything else was dangerous or damageing.