I down-shift too early?

[phylet]

I recently joined the Leicester IAM group: Had two drives so far and im fairly happy with it; its not perfect, but an easy starting point before i goto the next level.


On my second drive i was approaching a roundabout when my observer disagreed with my method.

I was traveling at 30mph (the limit). And upon approach could not see the extent of the roundabout. I blipped the throttle and put the car into second and slowed to 20mph.
If there was traffic i could have stopped, but as it was clear i easily and quickly moved out onto the roundabout.

My observer disagrees with what i did because if id had to stop it would have been a wasted gear change, i however feel that what i did let me engine brake to the speed i wanted without using the brakes; let me quickly progress onto the roundabout AND a down-shift doesnt go against my system of mechanical sympathy.


Whos right? help me understand his view point if it helps me pass through this level.


P.s. Michael from Leicester i be, if you be my observer, HI!

[vonhosen]

phylet said:

I recently joined the Leicester IAM group: Had two drives so far and im fairly happy with it; its not perfect, but an easy starting point before i goto the next level.


On my second drive i was approaching a roundabout when my observer disagreed with my method.

I was traveling at 30mph (the limit). And upon approach could not see the extent of the roundabout. I blipped the throttle and put the car into second and slowed to 20mph.
If there was traffic i could have stopped, but as it was clear i easily and quickly moved out onto the roundabout.

My observer disagrees with what i did because if id had to stop it would have been a wasted gear change, i however feel that what i did let me engine brake to the speed i wanted without using the brakes; let me quickly progress onto the roundabout AND a down-shift doesnt go against my system of mechanical sympathy.


Whos right? help me understand his view point if it helps me pass through this level.


P.s. Michael from Leicester i be, if you be my observer, HI!

You've joined a motoring organisation, presumably with a view to doing their test.
If you want to pass their test, then you'll be marked/judged against their system, not yours.
There are many ways to achieve an objective, some have advantages in one area, whilst others in another. The IAM have based their system on 'Roadcraft' & their system is what they'll look for you to drive to.

Edited by vonhosen on Sunday 10th May 00:00

[phylet]

vonhosen said:

I can do what they say, word for word, but i feel id learn more from it if i understand why it is they say to do it! Could you perhaps recommend some reading?

[vonhosen]

phylet said:

vonhosen said:

I can do what they say, word for word, but i feel id learn more from it if i understand why it is they say to do it! Could you perhaps recommend some reading?

Have you read roadcraft ?

[phylet]

No; i assume you'd recommend it? ill try to get a copy tomorrow!

[agent006]

vonhosen said:

You've joined a motoring organisation, presumably with a view to doing their test.
If you want to pass their test, then you'll be marked/judged against their system, not yours.
There are many ways to achieve an objective, some have advantages in one area, whilst others in another. The IAM have based their system on 'Roadcraft' & their system is what they'll look for you to drive to.

I asked the same question of my RoSPA observer when i was in an identical situation to the OP. He referred it up to the examiner and got pretty much the same response as above. Basically "you do it this way because we tell you to". There seems to be no discussion allowed.

[phylet]

My observer did discuss it with me, but the best we could agree on was that we had to do it their way. I tried to say that i had observed and broken the roundabout into two parts, the approach and joining, he sort-of saw what i was saying, but said to do it the other way...

[tenohfive]

If their system is based on roadcraft, I can explain the reason for this:

Roadcraft is based around, 'The system of car control.' What this means is its a way of approaching any hazard (such as a roundabout) and negotiating it in a safe manner.

This consists of Information - Position - Speed - Gear - Accelerate. Roadcraft explains it in more detail. The idea is that you run through each stage of this process at any given hazard, whilst constantly taking in information and if necessary re-entering at an earlier stage.

Aside from anything else, when applied to a roundabout its a smoother way of driving than what you did. You took in information but couldn't see if it was safe to go, so potentially you could have ended up stopping. So why do the gear change to slow? Why not brake until you could see its clear to go, then change gear to give you the right gear for acceleration then accelerate away?

Using the gears to brake isn't part of the system. I could speculate as to why this is (aside from as listed above) being that it puts strain on the clutch/gearbox, and obviously brake pads are cheaper than a gearbox in the long run.

Drive the way he tells you to and you'll start to see the benefits. Its only once you're used to driving that way that you'll see just how much smoother the negotiation of hazards becomes. In some cases it won't change anything (because you'll already drive that way, without thinking about it) but in others it might be a bit of an eye opener.

Edited by tenohfive on Sunday 10th May 04:45

[jbush]

tenohfive said:

Why not brake until you could see its clear to go, then change gear to give you the right gear for acceleration then accelerate away?

This seems to go against what they teach when you're learning though, when I learnt I was told to get into gear early so I have one less thing to think about when I get to the roundabout. The same applied when I did pass plus.

When I started learning I changed gear after assessing if I could still go, but it was slowly beaten out.

[p1esk]

agent006 said:

vonhosen said:

You've joined a motoring organisation, presumably with a view to doing their test.
If you want to pass their test, then you'll be marked/judged against their system, not yours.
There are many ways to achieve an objective, some have advantages in one area, whilst others in another. The IAM have based their system on 'Roadcraft' & their system is what they'll look for you to drive to.

I asked the same question of my RoSPA observer when i was in an identical situation to the OP. He referred it up to the examiner and got pretty much the same response as above. Basically "you do it this way because we tell you to". There seems to be no discussion allowed.

....and then they wonder why some Associates are not entirely happy with what they get from the IAM or RoSPA.

If you do happen to get a good Observer, be grateful for his assistance. I believe some can be extremely good, and all credit to them. It's just a pity about the damage done by some of the others.

Best wishes all,
Dave.

Edited by p1esk on Sunday 10th May 12:18

[1950trevorP]

phylet said:

I blipped the throttle and put the car into second and slowed to 20mph.

. . help me understand his view point if it helps me pass through this level.

An explanation should have been that using "The System", we do not use the gears to slow the vehicle.

An aim is to change gear without any change in vehicle road speed.
This requires "rev matching".

This, in turn, precludes braking and changing down at the same time.

(MUCH smoother for passengers.)

Do not fret - MANY students have problems with this "concept".

[Flibble]

Surely if he blipped the throttle he did rev match and there was no change in road speed during the gear change, only after? I'm not sure how this is incompatible with the system as you've described it.

[GreenV8S]

Although 'the system' does prescribe braking to the desired speed before changing gear, it also includes the use of acceleration sense to manage the speed. I don't see anything wrong with choosing a gear that gives the appropriate throttle authority for the circumstances, and if circumstances change I don't see anything wrong with changing gear to reflect that - for example on the approach to a junction where additional acceleration is likely to be required. It does not make sense to me to delay the gear change until you have decided to 'go' rather than 'stop'; by being prepared to go, you can respond quicker. The argument that you have potentially 'wasted' a gear change is imo silly. A great many things that drivers do are speculative and precautionary, that doesn't mean they shouldn't be done.

[Major Bloodnok]

I'd say it depends on forward visibility: in the situation described ("couldn't see the extent of the roundabout"), ISTM that braking in the current gear, with a change down and acceleration if appropriate when the view opens up would be the thing to do. If the visibility was good on the approach, then I don't see owt wrong with with a preparatory change down "for flexibility". As long as you're able to stop, it seems OK to me. As for the "unnecessary gear change" - that sounds a bit anal, and the sort of thing that can tick people off. Just say that you "restarted the system".

Acceleration sense and the ability to change gear without changing road speed are important skills, but these would be lost if one blindly stuck to the letter of the system, rather than its spirit.

[p1esk]

GreenV8S said:

Although 'the system' does prescribe braking to the desired speed before changing gear, it also includes the use of acceleration sense to manage the speed. I don't see anything wrong with choosing a gear that gives the appropriate throttle authority for the circumstances, and if circumstances change I don't see anything wrong with changing gear to reflect that - for example on the approach to a junction where additional acceleration is likely to be required. It does not make sense to me to delay the gear change until you have decided to 'go' rather than 'stop'; by being prepared to go, you can respond quicker. The argument that you have potentially 'wasted' a gear change is imo silly. A great many things that drivers do are speculative and precautionary, that doesn't mean they shouldn't be done.

Agreed. If the likes of the IAM and RoSPA wish to be so prescriptive about these things that's their affair, but looked at on a more free thinking basis they (and their methods) are not necessarily superior in the overall scheme of things. It seems to me that even the police driving schools - for whom 'the system' is a major feature of their training regime - are somewhat less anal about it all.

Best wishes all,
Dave.

[1950trevorP]

The words "prescriptive" "free thinking basis" "superior" and "anal"
are all of no help to the OP.

What he asked for was REASONS.

Opinions of "liking" the IAM or not does not exactly answer his query.

[RobM77]

I'm with the OP on his decision, because he's prepared himself for either possible scenario whilst in relatively calm space before the roundabout; he's then ready for whatever the roundabout throws at him (clear road, emergency braking/acceleration, traffic so needing to stop etc - all situations are covered). If he'd left it in 3rd and subsequently found the roundabout was clear, he'd be very close to a hazard whilst performing a gear change as well as the mirror checking, steering etc etc. I'm all for calm preparation and seperating tasks out, rather than ending up on top of a hazard doing everything at once. I must say though, in most of the road cars that I've driven 2nd's a bit too low a gear for 30mph - in my Lotus and BMW I'd be down to 25mph before changing down. A small point though - preparing for any situation before a hazard is, in my opinion, a good idea. I disagree with the observer.

One other thing to consider - I once approached a junction slowly and had someone come round a corner behind me unable to stop. Because I was in 2nd gear I was able to accelerate firmly out of the way to avoid being rear ended. If I was in 3rd gear I wouldn't have made it.

[p1esk]

1950trevorP said:

The words "prescriptive" "free thinking basis" "superior" and "anal"
are all of no help to the OP.

What he asked for was REASONS.

Opinions of "liking" the IAM or not does not exactly answer his query.

David acknowledges yet another ticking off by Trevor.

You should know by now, Trevor, that being constructive or helpful is beyond my capability. Getting ratty, or clowning, are my specialites.

Best wishes all,
Dave.

[p1esk]

1950trevorP said:

phylet said:

I blipped the throttle and put the car into second and slowed to 20mph.

. . help me understand his view point if it helps me pass through this level.

An explanation should have been that using "The System", we do not use the gears to slow the vehicle.

An aim is to change gear without any change in vehicle road speed.
This requires "rev matching".

This, in turn, precludes braking and changing down at the same time.

(MUCH smoother for passengers.)

Do not fret - MANY students have problems with this "concept".

Although I don't use the heel and toe technique, I understand this can give a very smooth and efficient result, so a downward gearchange can be combined with braking, but it doesn't appear to comply with 'the system.'

Best wishes all,
Dave.

[p1esk]

RobM77 said:

I'm with the OP on his decision, because he's prepared himself for either possible scenario whilst in relatively calm space before the roundabout; he's then ready for whatever the roundabout throws at him (clear road, emergency braking/acceleration, traffic so needing to stop etc - all situations are covered). If he'd left it in 3rd and subsequently found the roundabout was clear, he'd be very close to a hazard whilst performing a gear change as well as the mirror checking, steering etc etc. I'm all for calm preparation and seperating tasks out, rather than ending up on top of a hazard doing everything at once. I must say though, in most of the road cars that I've driven 2nd's a bit too low a gear for 30mph - in my Lotus and BMW I'd be down to 25mph before changing down. A small point though - preparing for any situation before a hazard is, in my opinion, a good idea. I disagree with the observer.

One other thing to consider - I once approached a junction slowly and had someone come round a corner behind me unable to stop. Because I was in 2nd gear I was able to accelerate firmly out of the way to avoid being rear ended. If I was in 3rd gear I wouldn't have made it.

That just goes to show that sticking with the conventional wisdom may not always be the best thing to do in all circumstances.

Incidentally, I think our 406 HDi will be happy to get down into 2nd gear at 30 mph if I choose to do it, and I would have thought that most cars could cope with that, without excessive engine speeds or other distress.

Best wishes all,
Dave.