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Jim Henderson wrote:
>
> Well, brakes tend to be "on or off", if you don't have ABS, pumping the
New car's brakes usually feel like that, but after a while one can found
a analog curve of braking power in even them.
> What I do on ice if accelerating is take my foot off the gas and drop the
> car to 3rd gear (I drive an automatic, but this works in a manual
> transmission car as well). Don't touch the brakes, because in general it
> won't do anything but cause you to lose control.
You don't have to slam the brakes, you know? The curve for braking power
is analog one (ie. non-digital), so you can amount any power between
minimum and maximum to the brakes (like you do at summer, just be more
careful). Naturally the feeling is different in different cars, but it's
still there, it just need a bit of practice.
> I also will occasionally tap the brakes to see if the car will slow
> down. It's important to do this while the wheels are pointing forward,
> though; if you do this and have the wheels turned, you could spin out of
> control if the circumstances are right.
Another way is to give some gas and check if the wheels start spinning.
On FWD car this won't make any kind of spinning of the car itself.
Naturally you'll need to know your tires to know how well you can brake
by this test.
> The best option is to find a different route if you encounter an icy hill
> - up or down.
If you'll need to get up an icy hill outside of public roads and have an
FWD car, go reverse - you'll gain more traction on the front wheels that
way.
> The important thing when driving on ice is to not make any sudden changes
> - sudden turns, slamming on the brakes, fast acceleration - all of these
> can cause a loss of control.
True. It's also a good habit to find a large field oslt to test out
these things. The better you'll feel the road and know the car, the
better your instincts will perform before you can think what's even
happening - therefore the better are your chances to survive ;).
> Jim
-Aero
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On Mon, 09 Feb 2009 19:06:29 +0200, Eero Ahonen wrote:
> Jim Henderson wrote:
>>
>> Well, brakes tend to be "on or off", if you don't have ABS, pumping the
>
> New car's brakes usually feel like that, but after a while one can found
> a analog curve of braking power in even them.
True.
>> What I do on ice if accelerating is take my foot off the gas and drop
>> the car to 3rd gear (I drive an automatic, but this works in a manual
>> transmission car as well). Don't touch the brakes, because in general
>> it won't do anything but cause you to lose control.
>
> You don't have to slam the brakes, you know? The curve for braking power
> is analog one (ie. non-digital), so you can amount any power between
> minimum and maximum to the brakes (like you do at summer, just be more
> careful). Naturally the feeling is different in different cars, but it's
> still there, it just need a bit of practice.
Well, I've only got something like 20 years of experience driving during
winters in Minnesota and Utah to call on. It's been my experience that
it is generally more effective to downshift and let the engine do the
work. Unless you know with relative precision how slippery it is,
tapping the breaks can be a bad prospect.
I've managed to put two cars in the ditch in 20 years. One from
overcorrecting a spin, and one for not slowing down enough because some
jackass was tailgating me. I've never managed to put my car in the ditch
by stepping on the brakes, because I was taught not to do that and I
don't. <shrug> I can't argue with what works for me.
>> I also will occasionally tap the brakes to see if the car will slow
>> down. It's important to do this while the wheels are pointing forward,
>> though; if you do this and have the wheels turned, you could spin out
>> of control if the circumstances are right.
>
> Another way is to give some gas and check if the wheels start spinning.
> On FWD car this won't make any kind of spinning of the car itself.
> Naturally you'll need to know your tires to know how well you can brake
> by this test.
Yes, that will also work, but yes, it is dependent on knowing the
condition of your tires. I think we both can agree that there is a high
degree of situational awareness called for.
>> The best option is to find a different route if you encounter an icy
>> hill - up or down.
>
> If you'll need to get up an icy hill outside of public roads and have an
> FWD car, go reverse - you'll gain more traction on the front wheels that
> way.
Yes, absolutely. In fact, I did get to do this a couple years ago -
started down a hill that was covered in ice, and after watching a car
come over and slam into a parked car and then the stop sign on the
opposite corner, I opted to back up and find another way down. Reverse
worked very well for that.
>> The important thing when driving on ice is to not make any sudden
>> changes - sudden turns, slamming on the brakes, fast acceleration - all
>> of these can cause a loss of control.
>
> True. It's also a good habit to find a large field oslt to test out
> these things. The better you'll feel the road and know the car, the
> better your instincts will perform before you can think what's even
> happening - therefore the better are your chances to survive ;).
Yes, agreed - the more you can practice in a safe environment, the better
prepared you'll be. :-)
Jim
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On Mon, 09 Feb 2009 12:00:33 +0100, scott wrote:
>> Well, brakes tend to be "on or off", if you don't have ABS, pumping the
>> brake pedal generally works well, but also if you can drop to a lower
>> gear, do that.
>
> Watch out though when changing down (in a manual), you might lock the
> driven wheels if you let up the clutch too quickly, in a rear wheel
> drive car this can give you a good wake up call :-)
Oh, yes, absolutely. I have an automatic now, but I learned on a
stick....and that does change the tactics.
>
>> I also will occasionally tap the brakes to see if the car will slow
>> down.
>
> Yep this is good advice, when it's safe to do so then *try out* how much
> grip you actually have, this will avoid a big surprise later up the road
> when you really do need to stop or turn quickly.
Yup.
Jim
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On Mon, 09 Feb 2009 18:55:20 +0200, Eero Ahonen wrote:
> scott wrote:
>>
>> Any wild movements are never good, even on wet or dry roads :-)
>>
>>
> But still they can be so fun! Oh, I really need a new RWD-wintertoy
> after I sold my old Volvo...
>
> -Aero
LOL, ain't that the truth...They can be fun in controlled circumstances,
hell, even after I spun my Ford Escort out (my first time off-road in a
car not designed for it), after making sure I was OK and the car wasn't
damaged, I thought that it seemed kinda fun.
Jim
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>> Any wild movements are never good, even on wet or dry roads :-)
>>
>
> But still they can be so fun!
Well of course if you are deliberately aiming for such things, I can never
resist blipping the accelerator on an empty snowy corner to get a bit of
sideways action :-D
If only I had the skill to do this with my car without crashing! (but not
the stupidity to do it while there's other traffic arround).
http://www.youtube.com/watch?v=buZ5407L718
> Oh, I really need a new RWD-wintertoy
> after I sold my old Volvo...
Hehe I love mine, but first I always have to hold down some button for 5
seconds to really turn off all the driving aids (just pressing it only turns
them half off). Actually 99% of the time I have all the driving aids turned
on (that's the default), they really are quite impressive at keeping the car
going the direction you are pointing.
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scott wrote:
>
> Well of course if you are deliberately aiming for such things, I can
> never resist blipping the accelerator on an empty snowy corner to get a
> bit of sideways action :-D
Doesn't help me, while I'm driving FWD as daily ride.
> If only I had the skill to do this with my car without crashing! (but
> not the stupidity to do it while there's other traffic arround).
>
> http://www.youtube.com/watch?v=buZ5407L718
Nnnnnice, proper 4WD sliding is always fun to watch, but as you say, it
doesn't belong there where this was shooted.
> Hehe I love mine, but first I always have to hold down some button for 5
> seconds to really turn off all the driving aids (just pressing it only
> turns them half off). Actually 99% of the time I have all the driving
> aids turned on (that's the default), they really are quite impressive at
> keeping the car going the direction you are pointing.
Same for me with ESP, even though most slides (practically all I've
faced) would piece of cake to take control or even get back controlled
by the natural movement of the car - Audi B8 is actually pretty easy and
nice to handle in such manners.
-Aero
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Jim Henderson wrote:
>
> Well, I've only got something like 20 years of experience driving during
> winters in Minnesota and Utah to call on.
I only have 10 in Finland :-). Honestly, I have no idea what kind of
winters there is at Utah or Minnesota, but I assume that means there's
snow and ice available enough.
> It's been my experience that
> it is generally more effective to downshift and let the engine do the
> work.
How could it be? In both styles the negative acceleration is applied to
the ground via tires and tire/ground -layer being the weakest part -
with downshifting most cars do it practically via 1 wheel, almost no car
makes it via 4 wheel (which would mean 4WD with completely locked
differentials), while brakes are applied via all 4 wheels. Breaking with
the engine is of course more economical
> Unless you know with relative precision how slippery it is,
> tapping the breaks can be a bad prospect.
There might be a language wall here - I'd consider tapping as a slight
touch and hitting the brakes as a 'do-not-do' -movement on ice.
> I've managed to put two cars in the ditch in 20 years. One from
> overcorrecting a spin, and one for not slowing down enough because some
> jackass was tailgating me. I've never managed to put my car in the ditch
> by stepping on the brakes, because I was taught not to do that and I
> don't. <shrug> I can't argue with what works for me.
We have the same ratio, I've put one in 10 years :). That was due to
lifting the gas pedal while coming back to my lane after overtaking
another car. And well, that was actually no ditch AFAIK, while the same
car is still mine and registered (just now out of the traffic, though -
it's my summer toy).
And I'm not saying that braking with the engine doesn't work - I'm
saying that braking with the brakes works too, it just needs to be done
carefully.
> Yes, that will also work, but yes, it is dependent on knowing the
> condition of your tires. I think we both can agree that there is a high
> degree of situational awareness called for.
*Everything* while driving on ice is dependent on knowing the condition
of tires, more or less. As pointed out, RWD can give you a spin (or try
it) with downshifting, if the road is too slippery. It's always
necessary to know what kind of tires you're driving on and what's their
condition. What I ment is that to test the possibilities to brake with
accelerating you'll need to know the ratio of acceleration traction and
braking traction of your tires. Eg. I once had tires (Kleber Kapnor 4
185/65/15) which were catastrophic when accelerating, but pretty good
when turning and braking.
> Yes, agreed - the more you can practice in a safe environment, the better
> prepared you'll be. :-)
And the more fun you'll have (while practicing, of course), so it's a
win-win situation :-).
> Jim
-Aero
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scott wrote:
> If only I had the skill to do this with my car without crashing!
I'm not sure it's his car. He has a price written on the window. :-)
I suspect he may be taking a used car for a test drive. ;-)
--
Darren New, San Diego CA, USA (PST)
"Ouch ouch ouch!"
"What's wrong? Noodles too hot?"
"No, I have Chopstick Tunnel Syndrome."
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On Tue, 10 Feb 2009 17:57:00 +0200, Eero Ahonen wrote:
> Jim Henderson wrote:
>>
>> Well, I've only got something like 20 years of experience driving
>> during winters in Minnesota and Utah to call on.
>
> I only have 10 in Finland :-). Honestly, I have no idea what kind of
> winters there is at Utah or Minnesota, but I assume that means there's
> snow and ice available enough.
Yes, and plenty of it in both places. Drove into work on ice and snow
today, in fact - and slid turning into the parking lot at work. :-)
>> It's been my experience that
>> it is generally more effective to downshift and let the engine do the
>> work.
>
> How could it be? In both styles the negative acceleration is applied to
> the ground via tires and tire/ground -layer being the weakest part -
> with downshifting most cars do it practically via 1 wheel, almost no car
> makes it via 4 wheel (which would mean 4WD with completely locked
> differentials), while brakes are applied via all 4 wheels. Breaking with
> the engine is of course more economical
By downshifting, what happens is the wheels aren't stopped, but the
torque applied through the drivetrain slows them down as the engine revs
come down. This has been my experience in 4 cars, including the first
car I drove (a manual) - but of course you have to be more careful in a
manual when downshifting - usually I'd start by just putting the clutch
in and letting the car coast. I did actually get to the point with that
car, though, that I could shift if I needed to without using the clutch,
just listen to the engine and when it got to the right speed, shifting
without the clutch wasn't a problem. I don't know if it's that easy to
do in newer manual transmission cars, though - that old car was a '74
Duster, manual *everything*, power *nothing*. ;-)
>> Unless you know with relative precision how slippery it is, tapping the
>> breaks can be a bad prospect.
>
> There might be a language wall here - I'd consider tapping as a slight
> touch and hitting the brakes as a 'do-not-do' -movement on ice.
It depends on the road conditions. For example, this morning as I turned
left into the parking lot at the office, the car's momentum overcame the
friction of the tires on the ice, and I ended up not turning as per usual
but sliding instead. In that case, pumping the breaks was an effective
way to slow the car down. Similar effect to a car with ABS (which I
really miss in my current car, my last one had ABS but the new one
doesn't), but the pulsing isn't rapid.
If a car has ABS, you can get away with hitting the breaks, because the
ABS system will prevent the wheels from locking up.
>> I've managed to put two cars in the ditch in 20 years. One from
>> overcorrecting a spin, and one for not slowing down enough because some
>> jackass was tailgating me. I've never managed to put my car in the
>> ditch by stepping on the brakes, because I was taught not to do that
>> and I don't. <shrug> I can't argue with what works for me.
>
> We have the same ratio, I've put one in 10 years :). That was due to
> lifting the gas pedal while coming back to my lane after overtaking
> another car. And well, that was actually no ditch AFAIK, while the same
> car is still mine and registered (just now out of the traffic, though -
> it's my summer toy).
:-)
> And I'm not saying that braking with the engine doesn't work - I'm
> saying that braking with the brakes works too, it just needs to be done
> carefully.
Yes, and I can agree with that. The problem is that most people don't do
it carefully enough, and end up like the SUV I saw on the way into work
today - wrecked.
>> Yes, that will also work, but yes, it is dependent on knowing the
>> condition of your tires. I think we both can agree that there is a
>> high degree of situational awareness called for.
>
> *Everything* while driving on ice is dependent on knowing the condition
> of tires, more or less. As pointed out, RWD can give you a spin (or try
> it) with downshifting, if the road is too slippery. It's always
> necessary to know what kind of tires you're driving on and what's their
> condition. What I ment is that to test the possibilities to brake with
> accelerating you'll need to know the ratio of acceleration traction and
> braking traction of your tires. Eg. I once had tires (Kleber Kapnor 4
> 185/65/15) which were catastrophic when accelerating, but pretty good
> when turning and braking.
We are in violent agreement. ;-)
>> Yes, agreed - the more you can practice in a safe environment, the
>> better prepared you'll be. :-)
>
> And the more fun you'll have (while practicing, of course), so it's a
> win-win situation :-).
:-)
Jim
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>> It's been my experience that
>> it is generally more effective to downshift and let the engine do the
>> work.
>
> How could it be? In both styles the negative acceleration is applied to
> the ground via tires and tire/ground -layer being the weakest part -
> with downshifting most cars do it practically via 1 wheel, almost no car
> makes it via 4 wheel (which would mean 4WD with completely locked
> differentials), while brakes are applied via all 4 wheels.
Maybe in some cars with sensitive brake pedals it's easier to control the
small amount of negative acceleration through the clutch/gears/accelerator
than through the brake pedal?
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