Re: clutch and pedal

In alt.usage.english, Robert Bannister wrote:
>Mike Barnes wrote:
>
>
>> Your response indicates that you didn't really absorb the points I was
>> trying to make. By "control" didn't mean control over which gear is
>> selected, I meant control over the car's speed and direction generally.
>> I think that's what people generally mean when they talk of a manual
>> giving better control.
>
>I really don't understand this. You control speed with the accelerator;
>you control direction with the steering wheel. Neither of these are
>different in manual or automatics.

OK, I'll try to explain. As I said earlier, these considerations mostly
apply to performance driving.

You are correct when you say that the accelerator controls speed, but of
course it controls the *engine* speed. It controls the *wheel* speed
only through the gearbox. That's why the gearbox makes a difference.
With a manual gearbox the engine and wheels are locked together so that
a ten percent change in engine speed equates to a ten percent change in
wheel speed. In an automatic, there's a fluid coupling called a "torque
converter" that allows the wheel speed to vary with regard to the engine
speed, without any change of gear. I think I probably don't need to
provide more detail for you to see that the presence of the torque
converter gives the driver less direct control over the speed of the
car. (Some readers are sure to be thinking that at cruise speeds, the
torque converter is locked. That is true, of course, but I'm talking of
about performance driving, not cruising.)

You're also correct when you say that the steering wheel controls the
car's direction, but the engine has its part to play as well. Imagine
what happens when you floor the accelerator in the middle of a tight
turn on a slippery surface. The driven wheels start to spin, and when
that happens they don't steer as well, and the car changes direction.
Performance drivers exploit that kind of effect to make turns faster
than is possible by steering alone. For instance, when drifting around a
corner, a rally driver sets the angle and direction of the car
principally with delicate use of the accelerator pedal, not with the
steering wheel (which is often pointing the wheels in a completely
different direction). See, for example, the extreme example at
<http://wallpapers.duble.com/2/Cars/Rally%20Car/7.jpg>. Again, I hope
that's enough detail to show that having a direct relationship between
engine speed and wheel speed (or, more particularly, engine torque and
torque at the wheels), as provided by a manual gearbox, provides the
driver with better control.

Although I've been talking about competitive driving, the issues I've
been talking about are important to anyone who likes to explore the
potential of their car. They also have application to ordinary drivers,
for example in conditions brought about by extreme weather, or in an
emergency situation. Generally, the skilled driver will fare better in a
manual than an automatic.

>> My first point is that when the driver moves an automatic's
>>accelerator
>> pedal, if the torque converter is active (i.e. you're not cruising), it
>> will blunt the effect of that movement. A fluid coupling is unavoidably
>> vaguer than a solid coupling. My second point is that having only (say)
>> three gears compared with six in a manual means that the engine speed is
>> less likely to be ideal. Both of these factors mean that the driver of a
>> traditional automatic is less able to exercise close control of the
>> vehicle, though obviously he/she is easily able to exercise sufficient
>> control for everyday driving. The best modern automatics manage to
>> minimise or even eliminate these disadvantages, but they're still
>> significant in most cars for any driver wanting to exploit the car's
>> full potential.
>
>I don't know where you get this idea about 3 speed gearboxes from.

Of course 3-speed gearboxes exist, but that was just an example. My
point is that automatic gearboxes generally have fewer gears than manual
gearboxes. Do you disagree with that?

> My last car certainly had four; my current car, it is true, has only
>three, because it is a very small car, but it has overdrive on second
>and top, giving it, in effect five gears. I can control all of these
>manually if I wish and when driving on mountain roads, I do.

OK, OK, you can control gear selection manually. You don't need to keep
telling me that - I heard you the first time. I'm not talking about that
sort of "control".

>I suspect all your acquaintance with automatics refers to the dim and
>distant past - the days when people would tell you that automatic
>gearboxes couldn't possibly work on anything smaller than a large
>truck.

You couldn't be more wrong. My current car is an automatic.

--
Mike Barnes
Cheshire, England
.

Relevant Pages

  • Re: 20 mph limit for urban streets to cut road deaths.
    ... At both speeds, you've sod all chance of even being ... circumstances and so lack adequate control. ... Public roads are not 'set aside' for car use. ...
    (uk.transport)
  • Re: Centering and throwing
    ... with some wheels maximum is so fast it can mean the clay taking control rather than being controlled, especially for those who are in the early stages of learning. ... I learnt on a seated Treadle Wheel with a one to one kick/rotation ... You start out patting the clay to center at a moderate to slow speed. ... Speeds that work for one person don't work for another. ...
    (rec.crafts.pottery)
  • Re: Absolute discharge for speeding PC
    ... but you made the point about car control above. ... would have the skill to control the car well at such speeds, ... It was a copper out having ...
    (uk.rec.driving)
  • Re: Hush
    ... but you always need two hands to control the vehicle properly. ... a car needs two hands. ... Chris has an automatic. ... it's possible that he has a steering wheel knob. ...
    (uk.rec.sheds)
  • Re: Renault suspended from European GP
    ... Red Bull released Vettel in last weekend's GP, knowing his car had some ... of control and crashed. ... weighs far more than just one wheel. ...
    (rec.autos.sport.f1)