Hydroplaning

Paul Cassel said:

Sheldon says that hydroplaning in bicycles isn't an issue and I
believe him. Here is the entry:

http://www.sheldonbrown.com/gloss_ho-z.html#hydroplaning

Quoted message said:

What bothers me about this chart is that the only metrics are
inflation and speed. I'd think that loading and perhaps tire shape
are also issues. Has anyone thought along similar lines?

These figures are for a smooth tire (essentially only traces of tread
or none) and a specific width. I have a feeling that the values are
correct for the test performed but that there are more parameters for
the general case.

As it says, it doesn't happen with bicycles, especially not with >30mm
cross section ties or knobbies. Round cross section tires as are
common on road bicycles and commercial aircraft form a canoe shaped
contact patch that is ideal for displacing water mass. After that,
fine granularity on pavement aggregate transmits traction from road to
tire. It's not the chip seal that does it but the roughness on the
surface of the chips of granite.

Quoted message said:

Has anyone here hydroplaned a bicycle - say a Pugsley?

Yes, on a frozen lake going straight ahead.

Jobst Brandt

Intuitively, I would also think width and tread pattern interfacing
water would be important, but have to give the benefit of doubt to
Sheldon verifying the most important variables. There's all kinds of
variables like temperature, etc... so unless someone makes conclusive
research on their own, then to verify you can only look at the
previous work of the author which in this case is spotless. Speed is
critical from my observations with any vehicle, with near proper
adusted tires. I forgot, but about 35mph +/-5mph, lift off. But the
kicker is you don't know what is below water, so you can't get too
confident sailing through puddles. Pooling water tends to carry rocks
and objects into the middle of the current. But the good thing is you
will slide with a lower coefficient of friction as long as a curb is
not in the way.

Paul Cassel said:

Sheldon says that hydroplaning in bicycles isn't an issue and I believe
him. Here is the entry:

http://www.sheldonbrown.com/gloss_ho-z.html#hydroplaning

What bothers me about this chart is that the only metrics are inflation
and speed. I'd think that loading and perhaps tire shape are also
issues. Has anyone thought along similar lines?

Has anyone here hydroplaned a bicycle - say a Pugsley?

Quoth Paul Cassel:

Quoted message said:

Sheldonsays that hydroplaning in bicycles isn't an issue and I believe
him. Here is the entry:

http://sheldonbrown.com/gloss_ho-z.html#hydroplaning

What bothers me about this chart is that the only metrics are inflation
and speed. I'd think that loading and perhaps tire shape are also
issues. Has anyone thought along similar lines?

I suspect tire shape does enter into it, and that a flat treaded tire,
such as a drag slick or other automotive tire would be more prone to
hydroplaning.

These figures come from the aeronautic industry, and airplanes use
round profile tires, as do bicycles.

Quoted message said:

Has anyone here hydroplaned a bicycle - say a Pugsley?

I once hydroplaned a car, an unforgettable experience. It only
lasted a second or two, and it was at least 40 years ago but it's
still fresh in my mind.

Sheldon "Whoooooooosh" Brown
+-----------------------------------------------------------+
| Oh freddled gruntbuggly |
| thy micturations are to me |
| As plurdled gabbleblotchits on a lurgid bee. |
| Groop I implore thee, my foonting turlingdromes. |
| And hooptiously drangle me with crinkly bind-lewurdles, |
| Or I will rend thee in the gobberwarts with my |
| blurglecruncheon, see if I don't! |
| -- Prostetnic Vogon Jeltz |
+-----------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Quoted message said:

Quoted message said:

Has anyone here hydroplaned a bicycle - say a Pugsley?

Yes, on a frozen lake going straight ahead.

Jobst Brandt

No hydroplaning here:
http://www.velomobiling.com/gallery/MNHPVA/2007IceBike/
FatTire200m.jpg.html

Jeff

Jeff Wills said:

Quoted message said:

Quoted message said:

Has anyone here hydroplaned a bicycle - say a Pugsley?

Quoted message said:

Quoted message said:

Yes, on a frozen lake going straight ahead.

Quoted message said:

No hydroplaning here:

http://www.velomobiling.com/gallery/MNHPVA/2007IceBike/FatTire200m.jpg.html

I think if you look more closely, you will see that the slick interface is
water and with the slightest slip, the contact with solid ice vanishes.
As I pointed out, riding on ice with a road bicycle on plain rubber tires
presents problems that are surmountable.

http://tinyurl.com/jfcvq

It was there that I discovered ABS for bicycles.

Jobst Brandt

In article <[email hidden]>,

Quoted message said:

Jeff Wills said:

Quoted message said:

> Has anyone here hydroplaned a bicycle - say a Pugsley?

Quoted message said:

Quoted message said:

Yes, on a frozen lake going straight ahead.

Quoted message said:

No hydroplaning here:

http://www.velomobiling.com/gallery/MNHPVA/2007IceBike/FatTire200m.jp
g.html

I think if you look more closely, you will see that the slick
interface is water and with the slightest slip, the contact with
solid ice vanishes. As I pointed out, riding on ice with a road
bicycle on plain rubber tires presents problems that are
surmountable.

Does one actually hydroplane on ice? Seems to me we are dealing with a
different phenomenon (lubrication). I remember back in high school
chemistry when ice skating was given as an example of Le Chatelier's
principle resulting in lubricity by changing the physical state of the
ice to a microscopic boundary of water, but bike tires are not ice
skates and do not create as much pressure on the ice. As well, there
seems to be some debate as to whether ice skatiung actually involves Le
Chatelier's principle:

http://home.pacbell.net/anamga/questions.html

"1.21 I have heard that you can skate on ice because the ice melts under
the blade pressure. Is this true?

"Liquid water occupies less volume than ice (this is a peculiar but well
known property of water); so, as a consequence of Le Chatelier's
principle compressing ice into a smaller volume will cause it to melt at
a lower temperature. This is, even nowadays, often considered to be the
main reason why ice skating is possible.

"However, a simple calculation demonstrates that this CANNOT be the true
explanation: The pressure created by the weight of a typical skater on
the blades is about 500 atmospheres, which only decreases the melting
point of ice to about -3.5 degrees C. However, the optimal temperature
for figure skating is between -5 and -6 degrees C. Hockey players prefer
even colder ice (around -9 or -10 degrees) and a very enthusiastic
outdoor skater could happily slide on ice at -20 degrees. Clearly, Le
Chatelier principle cannot be the explanation.

"Friction of the blade against the ice while skating causes heat, which
can contribute to melting the ice by warming. This process has been
confirmed to be more important than the pressure melting mentioned above
at low temperatures. However, friction melting does not explain why ice
is also slippery when not moving (a point you may be familiar with if
you have ever fallen while standing still at the barrier doing nothing).

"A more convincing explanation lies in the structure of ice: because the
water molecules on the ice surface are not surrounded fully by other
molecules they tend to adopt a denser, more disorganized and liquid-like
structure than the ordered regular hexagonal packing of bulk ice. This
quasi-liquid surface layer is thick enough to allow gliding down to -35
degrees."

I think there are some problems with this explanation, but it's
interesting.

Quoted message said:

http://tinyurl.com/jfcvq

It was there that I discovered ABS for bicycles.

Your brother brought a 1958 Chevy Impala to Europe?

Tim McNamara said:

Quoted message said:

Quoted message said:

>> Has anyone here hydroplaned a bicycle - say a Pugsley?

Quoted message said:

Quoted message said:

Quoted message said:

>Yes, on a frozen lake going straight ahead.

Quoted message said:

Quoted message said:

Quoted message said:

No hydroplaning here:

http://www.velomobiling.com/gallery/MNHPVA/2007IceBike/FatTire200m.jpg.html

Quoted message said:

Quoted message said:

I think if you look more closely, you will see that the slick
interface is water and with the slightest slip, the contact with
solid ice vanishes. As I pointed out, riding on ice with a road
bicycle on plain rubber tires presents problems that are
surmountable.

Quoted message said:

Does one actually hydroplane on ice? Seems to me we are dealing
with a different phenomenon (lubrication). I remember back in high
school chemistry when ice skating was given as an example of Le
Chatelier's principle resulting in lubricity by changing the
physical state of the ice to a microscopic boundary of water, but
bike tires are not ice skates and do not create as much pressure on
the ice. As well, there seems to be some debate as to whether ice
skatiung actually involves Le Chatelier's principle:

Quoted message said:

http://home.pacbell.net/anamga/questions.html

Quoted message said:

"1.21 I have heard that you can skate on ice because the ice melts
under the blade pressure. Is this true?"

You are correct but then the definition of hydroplaning is a little
vague since it is a condition where the tire no longer contacts the
road. The depth of water between tire and hard surface is not
mentioned in any reference I could find. Having observed
hydrodaynamics in various conditions, I am certain that water depth
under a hydroplaning tire is far smaller than people visualize,
typically in Wikipedia:

http://en.wikipedia.org/wiki/Aquaplaning

Quoted message said:

"Liquid water occupies less volume than ice (this is a peculiar but
well known property of water); so, as a consequence of Le
Chatelier's principle compressing ice into a smaller volume will
cause it to melt at a lower temperature. This is, even nowadays,
often considered to be the main reason why ice skating is possible.

Quoted message said:

"However, a simple calculation demonstrates that this CANNOT be the
true explanation: The pressure created by the weight of a typical
skater on the blades is about 500 atmospheres, which only decreases
the melting point of ice to about -3.5 degrees C. However, the
optimal temperature for figure skating is between -5 and -6 degrees
C. Hockey players prefer even colder ice (around -9 or -10 degrees)
and a very enthusiastic outdoor skater could happily slide on ice at
-20 degrees. Clearly, Le Chatelier principle cannot be the
explanation.

This calculation is made by people who do not understand asperity
contacts and are not tribologists. This subject goes on and on in
various discussions.

Quoted message said:

"Friction of the blade against the ice while skating causes heat,
which can contribute to melting the ice by warming. This process
has been confirmed to be more important than the pressure melting
mentioned above at low temperatures. However, friction melting does
not explain why ice is also slippery when not moving (a point you
may be familiar with if you have ever fallen while standing still at
the barrier doing nothing).

Quoted message said:

"A more convincing explanation lies in the structure of ice: because
the water molecules on the ice surface are not surrounded fully by
other molecules they tend to adopt a denser, more disorganized and
liquid-like structure than the ordered regular hexagonal packing of
bulk ice. This quasi-liquid surface layer is thick enough to allow
gliding down to -35 degrees."

So do you have a link to a scientific paper on the matter? The above
is a mix of conjecture and not enough science and seves to keep all
contentions afloat.

Quoted message said:

I think there are some problems with this explanation, but it's
interesting.

http://tinyurl.com/jfcvq

Quoted message said:

Quoted message said:

It was there that I discovered ABS for bicycles.

Quoted message said:

Your brother brought a 1958 Chevy Impala to Europe?

The US Army moved an officer's houshold goods to wherever they were
stationed, if it wasn't a war zone.

Jobst Brandt

In article <[email hidden]>,

Quoted message said:

http://tinyurl.com/jfcvq

Quoted message said:

Quoted message said:

It was there that I discovered ABS for bicycles.

Quoted message said:

Your brother brought a 1958 Chevy Impala to Europe?

The US Army moved an officer's houshold goods to wherever they were
stationed, if it wasn't a war zone.

I was just mentally picturing a '58 Impala parked next to a 2CV...

Tim McNamara writes:

http://tinyurl.com/jfcvq

Quoted message said:

Quoted message said:

Quoted message said:

> It was there that I discovered ABS for bicycles.

Quoted message said:

Quoted message said:

Quoted message said:

Your brother brought a 1958 Chevy Impala to Europe?

Quoted message said:

Quoted message said:

The US Army moved an officer's household goods to wherever they
were stationed, if it wasn't a war zone.

Quoted message said:

I was just mentally picturing a '58 Impala parked next to a 2CV...

Not to worry, there have always been large cars in Europe, just not
ones with which we identify. Beyond that, there were many US Forces
cars all over the "western" countries since WWII.

Jobst Brandt

Quoted message said:

Tim McNamara writes:

http://tinyurl.com/jfcvq

Quoted message said:

Quoted message said:

>> It was there that I discovered ABS for bicycles.

Quoted message said:

Quoted message said:

> Your brother brought a 1958 Chevy Impala to Europe?

Quoted message said:

Quoted message said:

The US Army moved an officer's household goods to wherever they
were stationed, if it wasn't a war zone.

Quoted message said:

I was just mentally picturing a '58 Impala parked next to a 2CV...

Rich Frenchmen were more into Cadillacs!

Quoted message said:

Not to worry, there have always been large cars in Europe,

post war until the sixties, American cars were not unusual in Europe.
When the economy expanded european manufacturers could afford to enter
the luxury segment of the market. So American cars were quickly pushed
out of the market by the home grown product
---
Marten Gerritsen

INFOapestaartjeM-GINEERINGpuntNL
www.m-gineering.nl

Quoted message said:

This calculation is made by people who do not understand asperity
contacts and are not tribologists. This subject goes on and on in
various discussions.

Quoted message said:

"Friction of the blade against the ice while skating causes heat,
which can contribute to melting the ice by warming. This process
has been confirmed to be more important than the pressure melting
mentioned above at low temperatures. However, friction melting does
not explain why ice is also slippery when not moving (a point you
may be familiar with if you have ever fallen while standing still at
the barrier doing nothing).
"A more convincing explanation lies in the structure of ice: because
the water molecules on the ice surface are not surrounded fully by
other molecules they tend to adopt a denser, more disorganized and
liquid-like structure than the ordered regular hexagonal packing of
bulk ice. This quasi-liquid surface layer is thick enough to allow
gliding down to -35 degrees."

So do you have a link to a scientific paper on the matter? The above
is a mix of conjecture and not enough science and seves to keep all
contentions afloat.

Quoted message said:

I think there are some problems with this explanation, but it's
interesting.

I saw the author of the paper gave a colloquium in the physics dept.
It was a few years ago, so it would take me a while to find it, but
Tim's summary is pretty much how I remember it.

On Jan 31, 2:40 am, "[email hidden]" <[email hidden]>

Quoted message said:

Quoted message said:

This calculation is made by people who do not understand asperity
contacts and are not tribologists. This subject goes on and on in
various discussions.

Quoted message said:

Quoted message said:

"Friction of the blade against the ice while skating causes heat,
which can contribute to melting the ice by warming. This process
has been confirmed to be more important than the pressure melting
mentioned above at low temperatures. However, friction melting does
not explain why ice is also slippery when not moving (a point you
may be familiar with if you have ever fallen while standing still at
the barrier doing nothing).
"A more convincing explanation lies in the structure of ice: because
the water molecules on the ice surface are not surrounded fully by
other molecules they tend to adopt a denser, more disorganized and
liquid-like structure than the ordered regular hexagonal packing of
bulk ice. This quasi-liquid surface layer is thick enough to allow
gliding down to -35 degrees."

Quoted message said:

So do you have a link to a scientific paper on the matter? The above
is a mix of conjecture and not enough science and seves to keep all
contentions afloat.

Quoted message said:

Quoted message said:

I think there are some problems with this explanation, but it's
interesting.

I saw the author of the paper gave a colloquium in the physics dept.
It was a few years ago, so it would take me a while to find it, but
Tim's summary is pretty much how I remember it.

Okay, it took me a while to find. The speaker was Robert Rosenberg and
apparently there still isn't a concensus on te topic.

This is a NY Times article about the same subject

http://www.nytimes.com/2006/02/21/science/21ice.html?ex=1298178000&en=5dc162576f801e16&ei=5088&partner=rssnyt&emc=rss

It was also the cover story of Physics Today Dec, 2005. You cannot
read those online unless you subsribe or have academic access.

http://www.physicstoday.org/vol-58/iss-12/contents.html

If you really want the papers with the research you can follow the
references in the latter article.