Avocet Touring Tires

[Benjamin Lewis]

[email protected] wrote:

> As I indicated before, there are many cases where hydroplaning is a
> serious problem, but road bicycles aren't among them. The formula given
> was: V(mph) >= 10 * sq.rt.[tire pressure(psi)], corresponding to the
> usual aviation formula which uses a multiplier of 9 since the velocity is
> given in knots rather than mph.% For bicycle road tires the pressures are
> usually at least 100 psi, so the speed needs to get up to about 100 mph
> before hydroplaning would be likely. But car tires are usually run at
> about 30 psi and then hydroplaning can occur at any speed above about 55
> mph. In that case it's a good idea to design the tire with grooves in
> the tread that minimize the chance of hydroplaning. One effect of the
> grooves is to increase the effective pressure of the line of tread
> between the grooves.

But a narrow tire doesn't achieve the same effect? Why do grooves
minimize the chances of hydroplaning, but tires that are the width of the
material between those grooves do not?

--
Benjamin Lewis

A small, but vocal, contingent even argues that tin is superior, but they
are held by most to be the lunatic fringe of Foil Deflector Beanie science.

 

[Peter]

Benjamin Lewis wrote:

> [email protected] wrote:
>
>
>>As I indicated before, there are many cases where hydroplaning is a
>>serious problem, but road bicycles aren't among them. The formula given
>>was: V(mph) >= 10 * sq.rt.[tire pressure(psi)], corresponding to the
>>usual aviation formula which uses a multiplier of 9 since the velocity is
>>given in knots rather than mph.% For bicycle road tires the pressures are
>>usually at least 100 psi, so the speed needs to get up to about 100 mph
>>before hydroplaning would be likely. But car tires are usually run at
>>about 30 psi and then hydroplaning can occur at any speed above about 55
>>mph. In that case it's a good idea to design the tire with grooves in
>>the tread that minimize the chance of hydroplaning. One effect of the
>>grooves is to increase the effective pressure of the line of tread
>>between the grooves.
>
>
> But a narrow tire doesn't achieve the same effect? Why do grooves
> minimize the chances of hydroplaning, but tires that are the width of the
> material between those grooves do not?

A narrow, high-pressure bicycle tire does achieve the same effect; i.e.
it isn't subject to hydroplaning at normal speeds. But there's no need
for any grooves or other tread pattern on the bike tires since they have
sufficient pressure already to avoid the problem.

 

[Tim McNamara]

John Forrest Tomlinson <[email protected]> writes:

> On 30 Jul 2004 17:49:47 +0100 (BST), David Damerell
> <[email protected]> wrote:
>
>> A total loss of wheel traction on a single-track vehicle will
>>result in an immediate sideways fall.
>
> I've skidded both wheels momentarily without falling. Isn't that a
> total loss of traction?

No, it's a partial loss. Try riding your bike on wet ice for a good
sense of total loss of traction. As soon as you lean at all away from
the vertical, you fall. Hmmm, be well padded! :-O

 

[John Forrest Tomlinson]

On Fri, 30 Jul 2004 23:04:03 -0400, Sheldon Brown
<[email protected]> wrote:

>David Damerell
>>
>>>A total loss of wheel traction on a single-track vehicle
>>>will result in an immediate sideways fall.
>>
>John Forrest Tomlinson wrote:
>>
>> I've skidded both wheels momentarily without falling. Isn't that a
>> total loss of traction?
>
>No. A normal skid is a _reduction_ of traction.
>
>A hydroplaning tire is slipperier than a tire on ice, there's basically
>zero traction.
>
>If you had ever experienced hydroplaning, you would know it.

Guess I haven't. I have ridden over black ice which was scary.

JT

 

[DRS]

"foldedpath" <[email protected]> wrote in message
news:[email protected]

[...]

> I'm wondering if modern (car) tire treads and lowered speed limits
> (compared to when I was a kid, driving my first car)... mean that
> fewer people these days actually know what true hydroplaning feels
> like?

Modern car tyres tend to be considerably wider than those of yore and
therefore on the face of it more susceptible to aquaplaning than the older,
narrower types, not less. The extra width and steel belting increase the
size of the contact patch considerably.

--

A: Top-posters.
Q: What is the most annoying thing on Usenet?

 

[Chris B.]

On Thu, 29 Jul 2004 18:46:54 -0400, Sheldon Brown
<[email protected]> wrote:

>I pontificated:
>
>>>hydroplaning is impossible for bicycles
>>
>Størker Moe asked:
>>
>> I don't disbelieve you, but why then do almost all tires for flat-bar
>> bikes have tread? I've hardly seen any 26" tire (or 28" non-racer bike
>> tire) with a smooth surface...
>
>In a word: marketing.
>
>It is very counterintuitive to ride on smooth tires. Most people, when
>they see slick tires, the first thing that goes through their head is
>the thought that they must be very slippery in wet conditions.

People who comment on the slick tires I use usually seem to think that
the tires are worn to the point of total baldness.

 

[Chris B.]

On Thu, 29 Jul 2004 20:46:27 +0100, "Trevor Jeffrey"
<[email protected]> wrote:

>
>Sheldon Brown wrote in message <[email protected]>...
>>
>>Hydroplaning is an issue for cars and motorcycles (though a rare one: in
>>my 44 years of driving, I've only experienced hydroplaning once.)
>>
>>However, hydroplaning is impossible for bicycles, so this is a non-issue.
>>
>
>Aquaplaning is the term, and certainly has happened to me riding a bicycle.
>Speed of about 40mph downhill, sheet of water over the road, bucketing it
>down. Apply brakes to slow to negotiate parked car, bike drifts towards
>gutter maintaining speed, look down, front wheel locked so release brakes.
>Balance was retained with slow response to steering efforts. Rare but
>possible.

Was the hub hanging from the top spokes at the time?

 

[Benjamin Lewis]

[email protected] wrote:

> Benjamin Lewis wrote:
>
>> [email protected] wrote:
>>
>>> As I indicated before, there are many cases where hydroplaning is a
>>> serious problem, but road bicycles aren't among them. The formula
>>> given was: V(mph) >= 10 * sq.rt.[tire pressure(psi)], corresponding to
>>> the usual aviation formula which uses a multiplier of 9 since the
>>> velocity is given in knots rather than mph.% For bicycle road tires the
>>> pressures are usually at least 100 psi, so the speed needs to get up to
>>> about 100 mph before hydroplaning would be likely. But car tires are
>>> usually run at about 30 psi and then hydroplaning can occur at any
>>> speed above about 55 mph. In that case it's a good idea to design the
>>> tire with grooves in the tread that minimize the chance of
>>> hydroplaning. One effect of the grooves is to increase the effective
>>> pressure of the line of tread between the grooves.
>> But a narrow tire doesn't achieve the same effect? Why do grooves
>> minimize the chances of hydroplaning, but tires that are the width of
>> the material between those grooves do not?
>
> A narrow, high-pressure bicycle tire does achieve the same effect;
> i.e. it isn't subject to hydroplaning at normal speeds. But there's no
> need for any grooves or other tread pattern on the bike tires since they
> have sufficient pressure already to avoid the problem.

I'm not disputing that bicycles may be able to hydroplane at extremely high
speeds. I just don't believe you can determine what that speed is by this
formula for airplane tires. I imagine this formula has been simplified,
and that it includes a bit of a "safety factor" to cope with this. Can you
provide a citation for the derivation of this formula?

--
Benjamin Lewis

A small, but vocal, contingent even argues that tin is superior, but they
are held by most to be the lunatic fringe of Foil Deflector Beanie science.

 

[Benjamin Lewis]

Chris B. wrote:

> On Thu, 29 Jul 2004 18:46:54 -0400, Sheldon Brown
> <[email protected]> wrote:
>
>> I pontificated:
>>
>>>> hydroplaning is impossible for bicycles
>>>
>> Størker Moe asked:
>>>
>>> I don't disbelieve you, but why then do almost all tires for flat-bar
>>> bikes have tread? I've hardly seen any 26" tire (or 28" non-racer bike
>>> tire) with a smooth surface...
>>
>> In a word: marketing.
>>
>> It is very counterintuitive to ride on smooth tires. Most people, when
>> they see slick tires, the first thing that goes through their head is
>> the thought that they must be very slippery in wet conditions.
>
> People who comment on the slick tires I use usually seem to think that
> the tires are worn to the point of total baldness.

I have a pair of completely slick "Specialized Fatboys" on one of my
bikes. The day after I bought them, someone remarked "wow, you must have
ridden a long way on those!" If he'd looked closer, he would have seen the
seam from the mold down the centre of the tire still visible.

--
Benjamin Lewis

A small, but vocal, contingent even argues that tin is superior, but they
are held by most to be the lunatic fringe of Foil Deflector Beanie science.

 

[Peter]

Benjamin Lewis wrote:

> [email protected] wrote:
>
>
>>Benjamin Lewis wrote:
>>
>>
>>>[email protected] wrote:
>>>
>>>
>>>>As I indicated before, there are many cases where hydroplaning is a
>>>>serious problem, but road bicycles aren't among them. The formula
>>>>given was: V(mph) >= 10 * sq.rt.[tire pressure(psi)], corresponding to
>>>>the usual aviation formula which uses a multiplier of 9 since the
>>>>velocity is given in knots rather than mph.% For bicycle road tires the
>>>>pressures are usually at least 100 psi, so the speed needs to get up to
>>>>about 100 mph before hydroplaning would be likely. But car tires are
>>>>usually run at about 30 psi and then hydroplaning can occur at any
>>>>speed above about 55 mph. In that case it's a good idea to design the
>>>>tire with grooves in the tread that minimize the chance of
>>>>hydroplaning. One effect of the grooves is to increase the effective
>>>>pressure of the line of tread between the grooves.
>>>
>>>But a narrow tire doesn't achieve the same effect? Why do grooves
>>>minimize the chances of hydroplaning, but tires that are the width of
>>>the material between those grooves do not?
>>
>>A narrow, high-pressure bicycle tire does achieve the same effect;
>>i.e. it isn't subject to hydroplaning at normal speeds. But there's no
>>need for any grooves or other tread pattern on the bike tires since they
>>have sufficient pressure already to avoid the problem.
>
>
> I'm not disputing that bicycles may be able to hydroplane at extremely high
> speeds. I just don't believe you can determine what that speed is by this
> formula for airplane tires.

If you have an alternative way of determining what speeds would be safe
from hydroplaning let's hear it.

> I imagine this formula has been simplified,
> and that it includes a bit of a "safety factor" to cope with this.

Even if true I fail to see what difference it makes. The formula as
given already indicates that bicycles won't hydroplane at speeds of less
than about 100 mph. It really doesn't matter to me if there's a safety
factor and I could really go up to say 150 mph - I have no intention of
ever reaching either speed on my bicycle.

> Can you
> provide a citation for the derivation of this formula?

Not really interested in working out a derivation. If you are I'd
suggest starting by considering the force required to move the water out
of the way and what's available from the pressure of the tire.

 

[Benjamin Lewis]

[email protected] wrote:

> Benjamin Lewis wrote:
>>
>> I'm not disputing that bicycles may be able to hydroplane at extremely
>> high speeds. I just don't believe you can determine what that speed is
>> by this formula for airplane tires.
>
> If you have an alternative way of determining what speeds would be safe
> from hydroplaning let's hear it.
>
>> I imagine this formula has been simplified,
>> and that it includes a bit of a "safety factor" to cope with this.
>
> Even if true I fail to see what difference it makes. The formula as
> given already indicates that bicycles won't hydroplane at speeds of less
> than about 100 mph. It really doesn't matter to me if there's a safety
> factor and I could really go up to say 150 mph - I have no intention of
> ever reaching either speed on my bicycle.

I do not know of another way to determine hydroplaning speeds barring more
experimentation. I agree with you that hydroplaning is not a problem on
bicycles; I think it's even *less* of a problem than is indicated by this
formula. I believe determining hydroplaning speeds would be a purely
academic exercise.

>> Can you provide a citation for the derivation of this formula?
>
> Not really interested in working out a derivation. If you are I'd
> suggest starting by considering the force required to move the water out
> of the way and what's available from the pressure of the tire.

I was asking for a citation, not a theoretical derivation. Where did you
get this formula from? Did they publish the data with which they derived
it?

--
Benjamin Lewis

A small, but vocal, contingent even argues that tin is superior, but they
are held by most to be the lunatic fringe of Foil Deflector Beanie science.

 

[Tom Sherman]

Sheldon Brown wrote:

> ...
> Hydroplaning is an issue for cars and motorcycles (though a rare one: in
> my 44 years of driving, I've only experienced hydroplaning once.)....

This proves that Mr. Brown is not sufficiently crazy with the use of the
"loud pedal".

--
Tom Sherman – Quad City Area

 

[Robin Hubert]

Mike DeMicco <[email protected]> wrote in message news:<[email protected]>...
> In article <[email protected]>,
> Sheldon Brown <[email protected]> wrote:
>
> > I pontificated:
> >
> > >>hydroplaning is impossible for bicycles
> > >
> Størker Moe asked:
> > >
> > > I don't disbelieve you, but why then do almost all tires for flat-bar
> > > bikes have tread? I've hardly seen any 26" tire (or 28" non-racer bike
> > > tire) with a smooth surface...
> >
> > In a word: marketing.
> >
>
> No, it's because flat bar bikes are mountain bikes or hybrids, meant to
> be ridden on dirt. Slicks work poorly on dirt but great on pavement.

This is not quite true either. Smooth tread (please, let's not
further the misconceptions by calling them "slicks") works fine on
dirt. "In" dirt is another thing. I ride on a variety of dirt
conditions with my smooth treaded road bike. The only place it is a
deficit is on wet dirt. Then, tread patterns help only if they can
dig in a bit.

Robin Hubert

 

[Tom Sherman]

Trevor Jeffrey wrote:

> ...In order for a bald tyre to function in the wet, extreme inflation
> pressure is required to attempt to match the penetrative qualities of a
> treaded tyre with its associated regions of high pressure. The extreme
> inflation pressure shortens the tyre contact patch to a length where
> insufficient lateral stability of the tyre is available resulting in
> skittish behaviour in the dry and sideslip in the wet though corners. The
> above is assuming a nominal wheel diameter of 27", riders of 48" wheels and
> above may find adequacy in bald, hard and narrow tyres....

I find the wet pavement traction of 44-406 Avocet Fasgrip Freestyle
"slick" tires to be quite adequate - much better than that of the 37-406
Primo Comets (with "herringbone" tread) that they replaced. Both types
of tires were inflated to about 90 psi.

--
Tom Sherman – Quad City Area

 

[Tom Sherman]

Chris B. wrote:

> On Thu, 29 Jul 2004 20:46:27 +0100, "Trevor Jeffrey"
> <[email protected]> wrote:
>
>
>>Sheldon Brown wrote in message <[email protected]>...
>>
>>>Hydroplaning is an issue for cars and motorcycles (though a rare one: in
>>>my 44 years of driving, I've only experienced hydroplaning once.)
>>>
>>>However, hydroplaning is impossible for bicycles, so this is a non-issue.
>>>
>>
>>Aquaplaning is the term, and certainly has happened to me riding a bicycle.
>>Speed of about 40mph downhill, sheet of water over the road, bucketing it
>>down. Apply brakes to slow to negotiate parked car, bike drifts towards
>>gutter maintaining speed, look down, front wheel locked so release brakes.
>>Balance was retained with slow response to steering efforts. Rare but
>>possible.
>
>
> Was the hub hanging from the top spokes at the time?

Hydroplaning can be prevented by riding a frame that is stiff, yet
compliant.

--
Tom Sherman – Quad City Area

 

[Sheldon Brown]

I wrote:

>>Hydroplaning is an issue for cars and motorcycles (though a rare one: in
>>my 44 years of driving, I've only experienced hydroplaning once.)
>>
>>However, hydroplaning is impossible for bicycles, so this is a non-issue.
>>
Trevor Jeffrey wrote:
>
> Aquaplaning is the term,

Aquaplaning is the term in British usage, but I'm an American, so I
commonly use the American term "hydroplaning."

I'll grant that "aquaplaning" is more linguistically pure, since it is
compounded of two Latin roots, rather than Latin mixed with Greek as
with "hydroplaning" but "hydroplaning" is the more standardd usage in
American English.

I'm getting tyred of this sort of condescending carping from the other
side of the Pond.

Since the automobile/motorcar was invented after American independence,
practically every technical term relating to motor vehicles is different
depending on which side of the Atlantic you live on. This doesn't mean
that one usage is "right" and that the other is "wrong." Deal with it.

Sheldon "Bilingual In English" Brown
+---------------------------------------------------+
| Two countries, divided by a common language. |
| -- George Bernard Shaw |
+---------------------------------------------------+
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

 

[Robert]

Tom Sherman wrote:
> Chris B. wrote:
>
>> On Thu, 29 Jul 2004 20:46:27 +0100, "Trevor Jeffrey"
>> <[email protected]> wrote:
>>
>>
>>> Sheldon Brown wrote in message <[email protected]>...
>>>
>>>> Hydroplaning is an issue for cars and motorcycles (though a rare
>>>> one: in
>>>> my 44 years of driving, I've only experienced hydroplaning once.)
>>>>
>>>> However, hydroplaning is impossible for bicycles, so this is a
>>>> non-issue.
>>>>
>>>
>>> Aquaplaning is the term, and certainly has happened to me riding a
>>> bicycle.
>>> Speed of about 40mph downhill, sheet of water over the road,
>>> bucketing it
>>> down. Apply brakes to slow to negotiate parked car, bike drifts
>>> towards
>>> gutter maintaining speed, look down, front wheel locked so release
>>> brakes.
>>> Balance was retained with slow response to steering efforts. Rare but
>>> possible.
>>
>>
>>
>> Was the hub hanging from the top spokes at the time?
>
>
> Hydroplaning can be prevented by riding a frame that is stiff, yet
> compliant.
>

I've been following this intriguing thread the past day or so. Amazing
stuff, what you people get up to.

Not even the pro riders can make their bikes aquaplane. And I thought
*they* were fast.

Loss of grip when cornering or braking is one thing. Increase of slip
angle is what happens in the wet, when cornering. But you people must be
a completely different class of riders to be able to go so quickly that
you can cause genuine aquaplaning, and then live to tell the story.

For my own part, I have no problem keeping an acceptable level of grip
on my normal road bike doing 60 km/h downhill in the rain, with
treadless tyres. A bit of common sense is needed to keep skull intact,
is all.

Maybe the solution is for you guys just to slow down a bit when the grip
is bad?

/Robert

 

[Trevor Jeffrey]

Chris B. wrote in message ...
>Was the hub hanging from the top spokes at the time?
No it was attempting a tango with the headset whilst striking up a tune with
the spokes.
TJ

 

[Trevor Jeffrey]

Tom Sherman wrote in message <[email protected]>...
>Sheldon Brown wrote:
>
>> ...
>> Hydroplaning is an issue for cars and motorcycles (though a rare one: in
>> my 44 years of driving, I've only experienced hydroplaning once.)....
>
>This proves that Mr. Brown is not sufficiently crazy with the use of the
>"loud pedal".
>
>--
>Tom Sherman – Quad City Area
>
In 20 years of driving I have never experienced hydroplaning. Aquaplaning
many times. I enjoyed overtaking Porches especially and would push that bit
harder until loss of steering became apparent, lovely smooth ride. Previous
employment required approx.. 70,000 miles per year driving quickly, mostly
on minor roads. With such intensive amount of high speed driving I learnt
very quickly how far I could push different vehicles. Learnt and used
handling characteristics to drive underpowered vehicles sometimes overloaded
at maximum safe speed.
Sufficiently crazy, I'd say so.
TJ

 

[Benjamin Lewis]

Trevor Jeffrey wrote:

>
> Tom Sherman wrote in message <[email protected]>...
>> Sheldon Brown wrote:
>>
>>> ... Hydroplaning is an issue for cars and motorcycles (though a rare
>>> one: in my 44 years of driving, I've only experienced hydroplaning
>>> once.)....
>>
>> This proves that Mr. Brown is not sufficiently crazy with the use of the
>> "loud pedal".
>>
> In 20 years of driving I have never experienced hydroplaning.
> Aquaplaning many times.

That's funny, considering these are both accepted words for describing the
same phenomenon. You're not one of those peddants, are you?

--
Benjamin Lewis

Seeing is deceiving. It's eating that's believing.
-- James Thurber