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A question for all mechanic type people



Stat Brother

Well-known member
NSC Patron
Jul 11, 2003
73,888
West west west Sussex
This morning I popped along to my local Speed Awareness course.
It was jolly nice of them to invite me.

Fella was talking about being aware of your speed in urban areas.
'Third for thirty'.

The theory being people trained to 'get through the gears, as soon as possible' are more likely to be in fourth, and therefore more likely to be driving in excess of 30, nearer 40mph, in 30 limits.
Also linking this to reducing your petrol consumption.

For those of us automatic drivers, he suggested, for urban driving, switching to the manual setting.

My question is:-

Assuming all of that is correct, are there any other drawbacks to driving an automatic in manual, for stop/start journeys?
I don't imagine it's that cost effective, if the gearbox falls out of the bottom of the car, because it's designed to be used only in 'D'rive.
 




CheeseRolls

Well-known member
NSC Patron
Jan 27, 2009
6,234
Shoreham Beach
This morning I popped along to my local Speed Awareness course.
It was jolly nice of them to invite me.

Fella was talking about being aware of your speed in urban areas.
'Third for thirty'.

The theory being people trained to 'get through the gears, as soon as possible' are more likely to be in fourth, and therefore more likely to be driving in excess of 30, nearer 40mph, in 30 limits.
Also linking this to reducing your petrol consumption.

For those of us automatic drivers, he suggested, for urban driving, switching to the manual setting.

My question is:-

Assuming all of that is correct, are there any other drawbacks to driving an automatic in manual, for stop/start journeys?
I don't imagine it's that cost effective, if the gearbox falls out of the bottom of the car, because it's designed to be used only in 'D'rive.

I have a Ford CMax,which switches the engine off automatically, when stopped with your foot off the clutch and restarts when the clutch is engaged again. It also has a display showing you which gear you should be driving in and for this car fourth is recommended for 30 MPH. It makes no difference what speed you change up through the gears. I tend to pay attention to this and change up and down as recommended, my missus on the other hand knows better, sigh.
 


Stat Brother

Well-known member
NSC Patron
Jul 11, 2003
73,888
West west west Sussex
It also has a display showing you which gear you should be driving in and for this car fourth is recommended for 30 MPH.
The fella said that's because the car is anticipating you wanting to drive upwards of 30mph when you reach 30, which clearly you won't be doing because you are in a 30 limit. :wink:
 


CheeseRolls

Well-known member
NSC Patron
Jan 27, 2009
6,234
Shoreham Beach
The fella said that's because the car is anticipating you wanting to drive upwards of 30mph when you reach 30, which clearly you won't be doing because you are in a 30 limit. :wink:

Well of course he is running the course, so he is in fact right - but up until the point I get "invited" to one of these events, I will go with the manufacturers recommendation.
 


Fungus

Well-known member
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May 21, 2004
7,160
Truro
How many autos have manual over-ride? My Jazz has "paddles" I could use, but I've only ever wanted them in the snow. Surely the whole point of an auto is so you don't have to bother with gear changing around town? Then it's easier to concentrate on the traffic!
 




Stat Brother

Well-known member
NSC Patron
Jul 11, 2003
73,888
West west west Sussex
How many autos have manual over-ride? My Jazz has "paddles" I could use, but I've only ever wanted them in the snow. Surely the whole point of an auto is so you don't have to bother with gear changing around town? Then it's easier to concentrate on the traffic!
Kind of my point.

Would 'excess' use of the manual override damage an automatic gearbox?
 


Horton's halftime iceberg

Blooming Marvellous
Jan 9, 2005
16,491
Brighton
I have an automatic and I use three functions D - Go, R - Go Backwards, P - When stopped

We are 20 mile an hour around here so I have no idea how the manual bit works...
 
















gazingdown

Well-known member
Feb 26, 2011
1,073
Cars have different gear ratios, to say stay in 3rd at 30mph is both over simplistic and wrong. In some cars this will mean the car is more responsive (and more likely to speed up if you press the throttle a bit).

Being in 3rd at 30 rather than 4th could mean you use MORE fuel, not less. Don't use too low a gear that the engine labours though, this uses more fuel and you will have a lack of control.

Automatic cars "know" what is the best gear to be in (and in many modern cars will use the best for economy, esp when on a light throttle).

How fast you go is down to how far/long you press the throttle, not what gear you are in (manual or automatic).

Use the right gear is good advise in general, the right gear for the conditions, for control, depending on the car too (gear ratios are different in different cars etc.) and in most cars it will "feel right" when you are in the right gear for the conditions/speed etc.
 






PILTDOWN MAN

Well-known member
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Sep 15, 2004
19,642
Hurst Green
Using the gear change on an automatic changes nothing, if you select 3 the auto box still uses 1,2 and then remains in 3 at the top speed. Select 2 it uses 1 and 2 and so on.

This guy is talking out of his backside.
 


gazingdown

Well-known member
Feb 26, 2011
1,073
Using the gear change on an automatic changes nothing, if you select 3 the auto box still uses 1,2 and then remains in 3 at the top speed. Select 2 it uses 1 and 2 and so on.

In many autos, the manual shift is (as you say) really a "max" gear, however many autos are a bit more obedient than that (but will override your decision if appropriate.

For example, at 30, my car will change down to 2nd if I tell it to and also go up to 4/5/6th (well, not tried to go up to 6th manually like that as no point).
 


grubbyhands

Well-known member
Dec 8, 2011
2,299
Godalming
Better advice would be to keep an eye on the speedometer, too obvious...I find it works for me. The 3rd at 30 is b*llox as suggested by a previous poster as the gear ratios for 3rd vary enormously from car to car.Makes you wonder what qualifications someone who makes a remark like that actually has. Probably some bleeding heart non driving rambler type. ( awaits flaming from rambler types inevitably)
 


Cheshire Cat

The most curious thing..
It seems to be a general instruction on these courses as a work colleague mentioned the same thing today - from his second speed awareness course.
 


Fungus

Well-known member
NSC Patron
May 21, 2004
7,160
Truro
Automatic cars "know" what is the best gear to be in (and in many modern cars will use the best for economy, esp when on a light throttle).

This. And mine is CVT - "continuously variable transmission" - so there is no 1, 2, 3, 4, just a stretchy rubber band. (Or something like that.)
 


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