First drive in snow probs: Tires, I hope...ABS brakes frightening
#1
Guest
Posts: n/a
First drive in snow probs: Tires, I hope...ABS brakes frightening
I recently drove my 99.5 A4 Quattro in the first northeast snow of the
season, and must say that I was disappointed.
The "forward traction" is excellent--I would not expect otherwise from
Quattro drive, but lateral traction is the pits! I almost took out a
few mailboxes while taking relatively gentle curves at fairly
reasonable speeds. The rear ends tendency to break seems excessive.
I was stunned. Heck--the whole heavy box wants to break and slide,
Please tell me that this problem is do the usage of Potenza RE950 all
weather high performance tires. My old 89 Saab 900S had only average
all weather Michelins and didn't have nearly the tendency to break
free and slide in turns. That FWD Saab handled snow like a manic. I'm
assuming someones going to suggest real snow tires will fix this
problem. The RE950s don't get stellar snow performance ratings at
tirerack.com. They are fab in all other conditions.
And oh yes---those stinking ABS brakes. This is my first experience
with them and they psychedelic. I can't tell if the system is actually
improving braking performance or not--in a juicy slushy situation,
you're virtually out of the loop, only providing primary break
pressure like a drone, waiting to see what magical horrors are up
ABS's sleeve.
What a bizarre sensation as that thing takes over and induces a
sense of no control whatsoever. That gritty unpredictable pumping
sensation. Can ABS be disabled? Bleech.
Dave
season, and must say that I was disappointed.
The "forward traction" is excellent--I would not expect otherwise from
Quattro drive, but lateral traction is the pits! I almost took out a
few mailboxes while taking relatively gentle curves at fairly
reasonable speeds. The rear ends tendency to break seems excessive.
I was stunned. Heck--the whole heavy box wants to break and slide,
Please tell me that this problem is do the usage of Potenza RE950 all
weather high performance tires. My old 89 Saab 900S had only average
all weather Michelins and didn't have nearly the tendency to break
free and slide in turns. That FWD Saab handled snow like a manic. I'm
assuming someones going to suggest real snow tires will fix this
problem. The RE950s don't get stellar snow performance ratings at
tirerack.com. They are fab in all other conditions.
And oh yes---those stinking ABS brakes. This is my first experience
with them and they psychedelic. I can't tell if the system is actually
improving braking performance or not--in a juicy slushy situation,
you're virtually out of the loop, only providing primary break
pressure like a drone, waiting to see what magical horrors are up
ABS's sleeve.
What a bizarre sensation as that thing takes over and induces a
sense of no control whatsoever. That gritty unpredictable pumping
sensation. Can ABS be disabled? Bleech.
Dave
#2
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakes frightening
"Interious" <ddhartwick@DELETESPAMBLOCKearthlink.net> wrote in message
news:bh8btv4qfv1ouvevbsk12mo7g8v2h7amd5@4ax.com...
> I recently drove my 99.5 A4 Quattro in the first northeast snow of the
> season, and must say that I was disappointed.
>
> The "forward traction" is excellent--I would not expect otherwise from
> Quattro drive, but lateral traction is the pits! I almost took out a
> few mailboxes while taking relatively gentle curves at fairly
> reasonable speeds. The rear ends tendency to break seems excessive.
> I was stunned. Heck--the whole heavy box wants to break and slide,
>
> Please tell me that this problem is do the usage of Potenza RE950 all
> weather high performance tires. My old 89 Saab 900S had only average
> all weather Michelins and didn't have nearly the tendency to break
> free and slide in turns. That FWD Saab handled snow like a manic. I'm
> assuming someones going to suggest real snow tires will fix this
> problem. The RE950s don't get stellar snow performance ratings at
> tirerack.com. They are fab in all other conditions.
>
> And oh yes---those stinking ABS brakes. This is my first experience
> with them and they psychedelic. I can't tell if the system is actually
> improving braking performance or not--in a juicy slushy situation,
> you're virtually out of the loop, only providing primary break
> pressure like a drone, waiting to see what magical horrors are up
> ABS's sleeve.
> What a bizarre sensation as that thing takes over and induces a
> sense of no control whatsoever. That gritty unpredictable pumping
> sensation. Can ABS be disabled? Bleech.
>
> Dave
>
First of all, ABS is better and faster than you'll ever be able to dose
yourself. ABS also keeps the car in curves while breaking.
Secondly, Audi awd doesn't overrule the natural forces. If you want to
really play with it I suggest you attend one of these Audi workshops in snow
conditions, they're really good!
Last but not least, real winter tires are much better than all others in the
cold, not a bit, a lot!
Ronald
#3
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakes frightening
On Tue, 09 Dec 2003 05:54:10 -0500, Interious
<ddhartwick@DELETESPAMBLOCKearthlink.net> wrote:
>problem. The RE950s don't get stellar snow performance ratings at
>tirerack.com. They are fab in all other conditions.
Get snow tires, really.
>And oh yes---those stinking ABS brakes. This is my first experience
>with them and they psychedelic. I can't tell if the system is actually
>improving braking performance or not--in a juicy slushy situation,
>you're virtually out of the loop, only providing primary break
>pressure like a drone, waiting to see what magical horrors are up
>ABS's sleeve.
One thing: Despite the ABS, if you want to brake well, slam the brakes
as hard as you can even with the ABS on. The force on the brake is
still determined by the pressure of your foot and not by a
brake-by-wire-automatic-full-braking-servo.
The ABS only makes your car steerable while on the brakes and it
remains under control. It is not a solution for poor driving skills
(not implying YOU have poor driving skills here).
Regards
Wolfgang
--
* Audi A6 Avant TDI *
* reply to wolfgang dot pawlinetz at chello dot at *
<ddhartwick@DELETESPAMBLOCKearthlink.net> wrote:
>problem. The RE950s don't get stellar snow performance ratings at
>tirerack.com. They are fab in all other conditions.
Get snow tires, really.
>And oh yes---those stinking ABS brakes. This is my first experience
>with them and they psychedelic. I can't tell if the system is actually
>improving braking performance or not--in a juicy slushy situation,
>you're virtually out of the loop, only providing primary break
>pressure like a drone, waiting to see what magical horrors are up
>ABS's sleeve.
One thing: Despite the ABS, if you want to brake well, slam the brakes
as hard as you can even with the ABS on. The force on the brake is
still determined by the pressure of your foot and not by a
brake-by-wire-automatic-full-braking-servo.
The ABS only makes your car steerable while on the brakes and it
remains under control. It is not a solution for poor driving skills
(not implying YOU have poor driving skills here).
Regards
Wolfgang
--
* Audi A6 Avant TDI *
* reply to wolfgang dot pawlinetz at chello dot at *
#4
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakes frightening
Hi,
I've got a 98 A6Q, 130K miles. Also got a UK racing licence, although
not sure that qualifies me to offer advice
Firstly, tyres ARE the most important item on your car. We have very
little snow in the UK. I use Goodyear F1's for the dry, wet and ice,
they are without doubt the best tyres I have ever tested. They are,
however, USELESS in the snow, so I have a friendly tyre dealer who
will put different tyres on when it snows.... And they really help.
Quattro can be both good and bad in snow and ice. The problem is, the
Audi system puts 25% of the power to each wheel unless one or more are
losing traction, meaning that if you are not accelerating, all four
wheels are locking up together when there is no traction. Also, all
modern cars are designd to understeer, and this can make the quattro a
real pig to drive in snow/ice/wet unless you know what to do.
ABS is the absolute worst ever invention for snow driving. The
problem is that snow has no grip, so the ABS doesn't actually do
ANYTHING. In the old days, when you locked your wheels in the snow, a
pile of snow built up in front of the wheels, and you were able to
also push the snow out of the way and maybe get down to the road, but
no longer. In the snow, best not to get into trouble in the first
place, but if you do, try to drive out of trouble, using the handbrake
(as long as you know what you are doing) can be your best ally.
Finally, if anyone has worked out how to disable the Audi ABS, please
let me know. I know someone said you'd never stop as quick without
them, but quite frankly, they are wrong. For someone that has just
the slightest driving talent, you can pull-up quicker without them.
The key issue is never panic-brake.
Ashley
On Tue, 09 Dec 2003 05:54:10 -0500, Interious
<ddhartwick@DELETESPAMBLOCKearthlink.net> wrote:
>I recently drove my 99.5 A4 Quattro in the first northeast snow of the
>season, and must say that I was disappointed.
>
>The "forward traction" is excellent--I would not expect otherwise from
>Quattro drive, but lateral traction is the pits! I almost took out a
>few mailboxes while taking relatively gentle curves at fairly
>reasonable speeds. The rear ends tendency to break seems excessive.
>I was stunned. Heck--the whole heavy box wants to break and slide,
>
>Please tell me that this problem is do the usage of Potenza RE950 all
>weather high performance tires. My old 89 Saab 900S had only average
>all weather Michelins and didn't have nearly the tendency to break
>free and slide in turns. That FWD Saab handled snow like a manic. I'm
>assuming someones going to suggest real snow tires will fix this
>problem. The RE950s don't get stellar snow performance ratings at
>tirerack.com. They are fab in all other conditions.
>
>And oh yes---those stinking ABS brakes. This is my first experience
>with them and they psychedelic. I can't tell if the system is actually
>improving braking performance or not--in a juicy slushy situation,
>you're virtually out of the loop, only providing primary break
>pressure like a drone, waiting to see what magical horrors are up
>ABS's sleeve.
>What a bizarre sensation as that thing takes over and induces a
>sense of no control whatsoever. That gritty unpredictable pumping
>sensation. Can ABS be disabled? Bleech.
>
>Dave
>
>
>
>************************************************* ****
>Ashley Shepherd
>email to ashley.shepherd_minusthespam_@virgin.net
>************************************************* ****
I've got a 98 A6Q, 130K miles. Also got a UK racing licence, although
not sure that qualifies me to offer advice
Firstly, tyres ARE the most important item on your car. We have very
little snow in the UK. I use Goodyear F1's for the dry, wet and ice,
they are without doubt the best tyres I have ever tested. They are,
however, USELESS in the snow, so I have a friendly tyre dealer who
will put different tyres on when it snows.... And they really help.
Quattro can be both good and bad in snow and ice. The problem is, the
Audi system puts 25% of the power to each wheel unless one or more are
losing traction, meaning that if you are not accelerating, all four
wheels are locking up together when there is no traction. Also, all
modern cars are designd to understeer, and this can make the quattro a
real pig to drive in snow/ice/wet unless you know what to do.
ABS is the absolute worst ever invention for snow driving. The
problem is that snow has no grip, so the ABS doesn't actually do
ANYTHING. In the old days, when you locked your wheels in the snow, a
pile of snow built up in front of the wheels, and you were able to
also push the snow out of the way and maybe get down to the road, but
no longer. In the snow, best not to get into trouble in the first
place, but if you do, try to drive out of trouble, using the handbrake
(as long as you know what you are doing) can be your best ally.
Finally, if anyone has worked out how to disable the Audi ABS, please
let me know. I know someone said you'd never stop as quick without
them, but quite frankly, they are wrong. For someone that has just
the slightest driving talent, you can pull-up quicker without them.
The key issue is never panic-brake.
Ashley
On Tue, 09 Dec 2003 05:54:10 -0500, Interious
<ddhartwick@DELETESPAMBLOCKearthlink.net> wrote:
>I recently drove my 99.5 A4 Quattro in the first northeast snow of the
>season, and must say that I was disappointed.
>
>The "forward traction" is excellent--I would not expect otherwise from
>Quattro drive, but lateral traction is the pits! I almost took out a
>few mailboxes while taking relatively gentle curves at fairly
>reasonable speeds. The rear ends tendency to break seems excessive.
>I was stunned. Heck--the whole heavy box wants to break and slide,
>
>Please tell me that this problem is do the usage of Potenza RE950 all
>weather high performance tires. My old 89 Saab 900S had only average
>all weather Michelins and didn't have nearly the tendency to break
>free and slide in turns. That FWD Saab handled snow like a manic. I'm
>assuming someones going to suggest real snow tires will fix this
>problem. The RE950s don't get stellar snow performance ratings at
>tirerack.com. They are fab in all other conditions.
>
>And oh yes---those stinking ABS brakes. This is my first experience
>with them and they psychedelic. I can't tell if the system is actually
>improving braking performance or not--in a juicy slushy situation,
>you're virtually out of the loop, only providing primary break
>pressure like a drone, waiting to see what magical horrors are up
>ABS's sleeve.
>What a bizarre sensation as that thing takes over and induces a
>sense of no control whatsoever. That gritty unpredictable pumping
>sensation. Can ABS be disabled? Bleech.
>
>Dave
>
>
>
>************************************************* ****
>Ashley Shepherd
>email to ashley.shepherd_minusthespam_@virgin.net
>************************************************* ****
#5
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakes frightening
On Tue, 09 Dec 2003 13:14:05 +0000, Ashley Shepherd
<ashley.shepherd_minusthespam_@virgin.net> wrote:
>Hi,
>
>I've got a 98 A6Q, 130K miles. Also got a UK racing licence, although
>not sure that qualifies me to offer advice
>
>Firstly, tyres ARE the most important item on your car.
ACK.
>ABS is the absolute worst ever invention for snow driving. The
>problem is that snow has no grip, so the ABS doesn't actually do
>ANYTHING.
That's a little harsh. In fact, the most common error is that drivers
are now not pressing the brake pedal as hard as they would without
ABS. You gotta practice that.
>In the old days, when you locked your wheels in the snow, a
>pile of snow built up in front of the wheels, and you were able to
>also push the snow out of the way and maybe get down to the road, but
>no longer.
The pile of snow itself would also slow you down.
>In the snow, best not to get into trouble in the first
>place, but if you do, try to drive out of trouble, using the handbrake
>(as long as you know what you are doing) can be your best ally.
Err.. I would agree if you do have a racing licence However, for
most folks on the road (using ABS) I would just say, carefully keep on
steering.
>Finally, if anyone has worked out how to disable the Audi ABS, please
>let me know. I know someone said you'd never stop as quick without
>them, but quite frankly, they are wrong.
Yes, they are wrong. ABS is not there for quicker braking (although on
dry roads it takes an experienced, well aware driver to outperform
it). The major advantage is that the average Joe (or Jane for that
matter ) can just slam down on the brakes without caring about
braking at the borderline of friction _and_ the car remains under
control, i.e. you can steer around obstacles.
>For someone that has just
>the slightest driving talent, you can pull-up quicker without them.
>The key issue is never panic-brake.
I agree, but IMO 8 out of 10 drivers _will_ panic brake and have never
trained braking, releasing the brake to steer clear and reapply the
brakes properly. ABS helps a lot there.
>Ashley
Oh, and I think just pulling the ABS fuse should do the trick.
Regards
Wolfgang
--
* Audi A6 Avant TDI *
* reply to wolfgang dot pawlinetz at chello dot at *
<ashley.shepherd_minusthespam_@virgin.net> wrote:
>Hi,
>
>I've got a 98 A6Q, 130K miles. Also got a UK racing licence, although
>not sure that qualifies me to offer advice
>
>Firstly, tyres ARE the most important item on your car.
ACK.
>ABS is the absolute worst ever invention for snow driving. The
>problem is that snow has no grip, so the ABS doesn't actually do
>ANYTHING.
That's a little harsh. In fact, the most common error is that drivers
are now not pressing the brake pedal as hard as they would without
ABS. You gotta practice that.
>In the old days, when you locked your wheels in the snow, a
>pile of snow built up in front of the wheels, and you were able to
>also push the snow out of the way and maybe get down to the road, but
>no longer.
The pile of snow itself would also slow you down.
>In the snow, best not to get into trouble in the first
>place, but if you do, try to drive out of trouble, using the handbrake
>(as long as you know what you are doing) can be your best ally.
Err.. I would agree if you do have a racing licence However, for
most folks on the road (using ABS) I would just say, carefully keep on
steering.
>Finally, if anyone has worked out how to disable the Audi ABS, please
>let me know. I know someone said you'd never stop as quick without
>them, but quite frankly, they are wrong.
Yes, they are wrong. ABS is not there for quicker braking (although on
dry roads it takes an experienced, well aware driver to outperform
it). The major advantage is that the average Joe (or Jane for that
matter ) can just slam down on the brakes without caring about
braking at the borderline of friction _and_ the car remains under
control, i.e. you can steer around obstacles.
>For someone that has just
>the slightest driving talent, you can pull-up quicker without them.
>The key issue is never panic-brake.
I agree, but IMO 8 out of 10 drivers _will_ panic brake and have never
trained braking, releasing the brake to steer clear and reapply the
brakes properly. ABS helps a lot there.
>Ashley
Oh, and I think just pulling the ABS fuse should do the trick.
Regards
Wolfgang
--
* Audi A6 Avant TDI *
* reply to wolfgang dot pawlinetz at chello dot at *
#6
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakes frightening
ddhartwick writes:
>I recently drove my 99.5 A4 Quattro in the first northeast snow of the
>season, and must say that I was disappointed
There is no such thing as an all season tire unless you live in Florida,
Southern Cal, etc. Buy a good set of snows for your A4 and you will have no
problems. You may have the "I-have-all-wheel-drive" syndrome which makes you
over confident. Check out the cars that are in the ditch or median on an
interstate during a snow storm. Many (most?) are 4x4 or all wheel drive
vehicles. Quattro doesn't compensate for poor driving habits. However, it is
very "forgiving" and in the hands of a good driver will out-perform just about
any other passenger car in adverse conditions.
ABS? Best thing since ! ABS does not mean you can stop quicker. In fact,
in deep snow or gravel roads, you get your best braking without abs. I had an
opportunity to test a car with/without ABS. With ABS, it stopped at 100 feet
from 50 mph. Without abs, I (and several other drivers) stopped the car in
less than 100 feet using threshold braking. We then took the car to a dirt
road and performed the same test. With the abs OFF, we stopped in 120 feet.
With abs ON, it took an amazing 180 feet to stop. It was a very eye-opening
experiment.
Audi used to have an on/off switch with their abs, but I can see where such an
arrangement would bring forth a plethora of law suits. ABS allows you to
*maintain* maximum braking while still being able to steer. In the "old days"
folks would jump on their brakes, lock up the fronts, and become an unsteerable
object. ABS does away with lock-up. However, poor driving habits still abound
with drivers jumping on their brakes, NOT steering, and still hitting the car
in front or whatever.
So, bottom line? Buy four steel wheels ($50/wheel), and mount some good snows
(Blizzacks?). I have been to Audi, Corvette, and BMW factory driving schools
(i.e. Audi Hands On) and cannot recomment too highly the knowledge/skill
attained from these courses. Next best thing would be a Sandy Stevens school
(northeast)
http://www.mv.com/ipusers/sadt/ or a Bud Stanley school (Florida)
http://www.autocontrolgsd.com/
These schools are inexpensive and concentrate on ABS braking and vehicle
handling. And if you mention my name, you may get a discount - I used to teach
in both schools, but health (and old age) has caused me to retire.
Dave
'03 RS-6 Avus and Ebony
http://hometown.aol.com/davplac/myhomepage/index.html
>I recently drove my 99.5 A4 Quattro in the first northeast snow of the
>season, and must say that I was disappointed
There is no such thing as an all season tire unless you live in Florida,
Southern Cal, etc. Buy a good set of snows for your A4 and you will have no
problems. You may have the "I-have-all-wheel-drive" syndrome which makes you
over confident. Check out the cars that are in the ditch or median on an
interstate during a snow storm. Many (most?) are 4x4 or all wheel drive
vehicles. Quattro doesn't compensate for poor driving habits. However, it is
very "forgiving" and in the hands of a good driver will out-perform just about
any other passenger car in adverse conditions.
ABS? Best thing since ! ABS does not mean you can stop quicker. In fact,
in deep snow or gravel roads, you get your best braking without abs. I had an
opportunity to test a car with/without ABS. With ABS, it stopped at 100 feet
from 50 mph. Without abs, I (and several other drivers) stopped the car in
less than 100 feet using threshold braking. We then took the car to a dirt
road and performed the same test. With the abs OFF, we stopped in 120 feet.
With abs ON, it took an amazing 180 feet to stop. It was a very eye-opening
experiment.
Audi used to have an on/off switch with their abs, but I can see where such an
arrangement would bring forth a plethora of law suits. ABS allows you to
*maintain* maximum braking while still being able to steer. In the "old days"
folks would jump on their brakes, lock up the fronts, and become an unsteerable
object. ABS does away with lock-up. However, poor driving habits still abound
with drivers jumping on their brakes, NOT steering, and still hitting the car
in front or whatever.
So, bottom line? Buy four steel wheels ($50/wheel), and mount some good snows
(Blizzacks?). I have been to Audi, Corvette, and BMW factory driving schools
(i.e. Audi Hands On) and cannot recomment too highly the knowledge/skill
attained from these courses. Next best thing would be a Sandy Stevens school
(northeast)
http://www.mv.com/ipusers/sadt/ or a Bud Stanley school (Florida)
http://www.autocontrolgsd.com/
These schools are inexpensive and concentrate on ABS braking and vehicle
handling. And if you mention my name, you may get a discount - I used to teach
in both schools, but health (and old age) has caused me to retire.
Dave
'03 RS-6 Avus and Ebony
http://hometown.aol.com/davplac/myhomepage/index.html
#7
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakesfrightening
> (not implying YOU have poor driving skills here).
I am, but in a nice way.
AWD is good for applying power to all four wheels. It does not, now follow
me here, improve coefficients of friction - in other words, traction.
Anti lock brakes categorically improve both braking performance and steering
while braking. There is absolutely no doubt about that. Multi million
dollar airliners - with which I am very familiar - take a huge penalty in
stopping distance on snow covered runways if their antilock systems are not
working properly. This fact is undeniable by anyone who has any information
on the subject. ABS works better than we do. It just feels funny.
Your experience goes to your learning. Congratulations. You are now a
better driver than a few weeks ago.
Snow tires create traction in snow. Some better than others.
Good luck, and slow down.
Grover
I am, but in a nice way.
AWD is good for applying power to all four wheels. It does not, now follow
me here, improve coefficients of friction - in other words, traction.
Anti lock brakes categorically improve both braking performance and steering
while braking. There is absolutely no doubt about that. Multi million
dollar airliners - with which I am very familiar - take a huge penalty in
stopping distance on snow covered runways if their antilock systems are not
working properly. This fact is undeniable by anyone who has any information
on the subject. ABS works better than we do. It just feels funny.
Your experience goes to your learning. Congratulations. You are now a
better driver than a few weeks ago.
Snow tires create traction in snow. Some better than others.
Good luck, and slow down.
Grover
#8
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakes
Grover writes:
>Anti lock brakes categorically improve both braking performance and steering
>while braking. There is absolutely no doubt about that.
Ahhh, but there is ":doubt about that." A trained driver can outperform ABS
*in a straight line* most of the time, using threshold braking. I've done it.
What abs allows is better steering performance (as you have stated). Problem
is, most folks will panic in an emergency and jump on their abs equipped brakes
and not steer, still hitting the vehicle in front of them (or whatever). On a
dirt/gravel road or in deep snow, the vehicle *without* abs will stop in a
shorter distance.
A problem first arose with abs when drivers would engage the abs and hear/feel
it working. They would do the worst thing possible - take their foot off of
the brake. Systems have improved since those first used in the 80s on
automobiles, but when abs first came out, there were a lot of problems with
drivers not used to the noise/feed back from the system.
Dave
'03 RS-6 Avus and Ebony
http://hometown.aol.com/davplac/myhomepage/index.html
>Anti lock brakes categorically improve both braking performance and steering
>while braking. There is absolutely no doubt about that.
Ahhh, but there is ":doubt about that." A trained driver can outperform ABS
*in a straight line* most of the time, using threshold braking. I've done it.
What abs allows is better steering performance (as you have stated). Problem
is, most folks will panic in an emergency and jump on their abs equipped brakes
and not steer, still hitting the vehicle in front of them (or whatever). On a
dirt/gravel road or in deep snow, the vehicle *without* abs will stop in a
shorter distance.
A problem first arose with abs when drivers would engage the abs and hear/feel
it working. They would do the worst thing possible - take their foot off of
the brake. Systems have improved since those first used in the 80s on
automobiles, but when abs first came out, there were a lot of problems with
drivers not used to the noise/feed back from the system.
Dave
'03 RS-6 Avus and Ebony
http://hometown.aol.com/davplac/myhomepage/index.html
#9
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakes frightening
X-no-archive: yes
"Ashley Shepherd" <ashley.shepherd_minusthespam_@virgin.net> wrote in
message news:kvhbtvg0cp0vifu236evbkd2b0od36hpce@4ax.com...
> Hi,
>
> I've got a 98 A6Q, 130K miles. Also got a UK racing licence, although
> not sure that qualifies me to offer advice
>
> Firstly, tyres ARE the most important item on your car. We have very
> little snow in the UK.
Clearly you dont live in Scotland!!
They get their fair share of snow up there, more the further north you go.
Its unusual for a year to go by without a reasonable amount of snow to fall.
Not enough to block you in but enough to make driving a real nuisance.
>I use Goodyear F1's for the dry, wet and ice,
> they are without doubt the best tyres I have ever tested. They are,
> however, USELESS in the snow, so I have a friendly tyre dealer who
> will put different tyres on when it snows.... And they really help.
Type?
> Finally, if anyone has worked out how to disable the Audi ABS, please
> let me know.
Doesn't the ABS system have its own fuse? Guess you could always remove
that one.
"Ashley Shepherd" <ashley.shepherd_minusthespam_@virgin.net> wrote in
message news:kvhbtvg0cp0vifu236evbkd2b0od36hpce@4ax.com...
> Hi,
>
> I've got a 98 A6Q, 130K miles. Also got a UK racing licence, although
> not sure that qualifies me to offer advice
>
> Firstly, tyres ARE the most important item on your car. We have very
> little snow in the UK.
Clearly you dont live in Scotland!!
They get their fair share of snow up there, more the further north you go.
Its unusual for a year to go by without a reasonable amount of snow to fall.
Not enough to block you in but enough to make driving a real nuisance.
>I use Goodyear F1's for the dry, wet and ice,
> they are without doubt the best tyres I have ever tested. They are,
> however, USELESS in the snow, so I have a friendly tyre dealer who
> will put different tyres on when it snows.... And they really help.
Type?
> Finally, if anyone has worked out how to disable the Audi ABS, please
> let me know.
Doesn't the ABS system have its own fuse? Guess you could always remove
that one.
#10
Guest
Posts: n/a
Re: First drive in snow probs: Tires, I hope...ABS brakesfrightening
"Grover" <ccleaveland@earthlink.nospam.net> wrote in message
news:BBFB2839.4B9F%ccleaveland@earthlink.nospam.ne t...
> > (not implying YOU have poor driving skills here).
>
> I am, but in a nice way.
>
> AWD is good for applying power to all four wheels. It does not, now
follow
> me here, improve coefficients of friction - in other words, traction.
>
> Anti lock brakes categorically improve both braking performance and
steering
> while braking. There is absolutely no doubt about that. Multi million
> dollar airliners - with which I am very familiar - take a huge penalty in
> stopping distance on snow covered runways if their antilock systems are
not
> working properly. This fact is undeniable by anyone who has any
information
> on the subject. ABS works better than we do. It just feels funny.
Right, that's sorted out airliners. Now back to cars..
A quick recap on Newtonian friction (it would be helpful to have a graph at
this point - if anyone can supply a link, then please do so!)
You apply a retarding force to something moving (e.g. applying the brakes)
and you get a roughly proportional force applied by the tyres themselves to
the road. Up to the static limit, that is (if memory serves - this may be
the wrong term in this context).
At this point, the tyre slips, the brakes grab, and you've locked your
wheel(s).
You can sort of duplicate this by tilting a flat surface with something
resting on it (e.g. your wallet on a book); when you tilt the book far
enough, the static limit is exceeded by gravity, and the wallet slides.
Back to cars, this has two effects. Firstly, you have reached the total
traction limit of the tyre, so applying a sideways motion ("arrrggh! Tree!
Tree! Steer left!") does absolutely nothing. <Crunch>.
Secondly, in real life, the coefficient of friction on a tyre will often
/drop/ when it locks, meaning that you're not decelerating as hard as you
might.
The technique of threshold (or cadence) braking is to try and get right up
to that breakaway point - where the tyre is working at its hardest - and
stay there.
A bump in the road, or a bit too much pressure, steering motion, or a gas
pocket in the pads can all cause you to exceed that limit and lock the
brakes. So you release the brakes (just enough to unlock the wheels) and try
again. "Cadence" - geddit?
ABS simply attempts to mimic that mechanically. But it doesn't have braking
"feel" - it simply pummels the brakes on each side of the static limit.
Theoretically, then, a human is capable of stopping in a shorter distance
than the type of ABS systems fitted to current cars. He can also steer,
assuming that he's not panic-braking. A Google should probally throw-up a
few tests - I've read a few in magazines where this has been demonstrated.
You don't need to have a racing license to do this - just practise (and
preferably off the public highways!).
An airliner, though? I dunno. And would this still hold true if the pilot
had sufficient brake feel and skill? Well, since someone like Boeing is
unlikely ever to expend the energy finding out, I'd say the point is a
little moot... personally, I'd hope that he'd concentrate on improving his
flying skills ;o)
> Your experience goes to your learning. Congratulations. You are now a
> better driver than a few weeks ago.
>
> Snow tires create traction in snow. Some better than others.
>
> Good luck, and slow down.
Good advice!
Particularly since ABS disperses that wedge of snow that would otherwise
slow you down. Mk.I ABS was even worse - it used to release the brakes
entirely if all four wheels locked, hence the off-switch on older Audis.
--
Hairy One Kenobi
Disclaimer: the opinions expressed in this opinion do not necessarily
reflect the opinions of the highly-opinionated person expressing the opinion
in the first place. So there!
news:BBFB2839.4B9F%ccleaveland@earthlink.nospam.ne t...
> > (not implying YOU have poor driving skills here).
>
> I am, but in a nice way.
>
> AWD is good for applying power to all four wheels. It does not, now
follow
> me here, improve coefficients of friction - in other words, traction.
>
> Anti lock brakes categorically improve both braking performance and
steering
> while braking. There is absolutely no doubt about that. Multi million
> dollar airliners - with which I am very familiar - take a huge penalty in
> stopping distance on snow covered runways if their antilock systems are
not
> working properly. This fact is undeniable by anyone who has any
information
> on the subject. ABS works better than we do. It just feels funny.
Right, that's sorted out airliners. Now back to cars..
A quick recap on Newtonian friction (it would be helpful to have a graph at
this point - if anyone can supply a link, then please do so!)
You apply a retarding force to something moving (e.g. applying the brakes)
and you get a roughly proportional force applied by the tyres themselves to
the road. Up to the static limit, that is (if memory serves - this may be
the wrong term in this context).
At this point, the tyre slips, the brakes grab, and you've locked your
wheel(s).
You can sort of duplicate this by tilting a flat surface with something
resting on it (e.g. your wallet on a book); when you tilt the book far
enough, the static limit is exceeded by gravity, and the wallet slides.
Back to cars, this has two effects. Firstly, you have reached the total
traction limit of the tyre, so applying a sideways motion ("arrrggh! Tree!
Tree! Steer left!") does absolutely nothing. <Crunch>.
Secondly, in real life, the coefficient of friction on a tyre will often
/drop/ when it locks, meaning that you're not decelerating as hard as you
might.
The technique of threshold (or cadence) braking is to try and get right up
to that breakaway point - where the tyre is working at its hardest - and
stay there.
A bump in the road, or a bit too much pressure, steering motion, or a gas
pocket in the pads can all cause you to exceed that limit and lock the
brakes. So you release the brakes (just enough to unlock the wheels) and try
again. "Cadence" - geddit?
ABS simply attempts to mimic that mechanically. But it doesn't have braking
"feel" - it simply pummels the brakes on each side of the static limit.
Theoretically, then, a human is capable of stopping in a shorter distance
than the type of ABS systems fitted to current cars. He can also steer,
assuming that he's not panic-braking. A Google should probally throw-up a
few tests - I've read a few in magazines where this has been demonstrated.
You don't need to have a racing license to do this - just practise (and
preferably off the public highways!).
An airliner, though? I dunno. And would this still hold true if the pilot
had sufficient brake feel and skill? Well, since someone like Boeing is
unlikely ever to expend the energy finding out, I'd say the point is a
little moot... personally, I'd hope that he'd concentrate on improving his
flying skills ;o)
> Your experience goes to your learning. Congratulations. You are now a
> better driver than a few weeks ago.
>
> Snow tires create traction in snow. Some better than others.
>
> Good luck, and slow down.
Good advice!
Particularly since ABS disperses that wedge of snow that would otherwise
slow you down. Mk.I ABS was even worse - it used to release the brakes
entirely if all four wheels locked, hence the off-switch on older Audis.
--
Hairy One Kenobi
Disclaimer: the opinions expressed in this opinion do not necessarily
reflect the opinions of the highly-opinionated person expressing the opinion
in the first place. So there!