Just curious ... tire question

The stresses in the contact patch differ due to the lubricating effects of the water. When a tire deforms to make the contact patch, the contact area contracts as it is now flat and not curved. On dry ground, this manifests itself as compressive stress in the rubber. Water lowers the coefficient of friction and lowers the compressive stress in the rubber, making it easier for a sharp stone, glass or other debris cut the tire. The water also lubricates the friction of the cutting edge, allowing it to penetrate deeper.

Wider tires require less pressure and have shorter contact patches. These add to puncture resistance, all other things considered equal.

psycholist wrote in message ...

Quoted message said:

Watching The Lance Interview while spinning on the rollers the other
evening, he commented on the poor judgement of teams like Phonak to ride
19mm tires during the TTT when Postal used "the fatest, ugliest tires we
could find." He said, "everyone knows that, in wet and rainy conditions,
you're more prone to flats and that's exactly what happened (to Phonak)."
(That's an approximate quote ... not an exact one.)

So the question is, why is this true? (And I know it is from personal
experience.) Why should a tire be more prone to a flat when the road is

wet

Quoted message said:

than if it's dry? I can't come up with any logical reason that should be
true. I'd intuitively opt for larger tires in those conditions for a

larger

Quoted message said:

contact patch and, hopefully, better handling in technical sections. But
what's up with flats in the wet?

In the dry rubber is resistant to cutting due to its high coefficient of
friction. Water acts as a lubricant and allows the thorn or glass shard to
penetrate with less force. The larger tyre allows a lower tyre pressure,
thereby reducing the force available to penetrate the tyre.

Trevor

On Wed, 18 Aug 2004 15:33:33 -0400, "psycholist" <[email hidden]>

Quoted message said:

Why should a tire be more prone
to a flat when the road is wet
than if it's dry?

The water lubricates objects on the road, so they can more easily
slice into the tire. Sometimes rain also washes more grit out onto
the road.

JT

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psycholist said:

Watching The Lance Interview while spinning on the rollers the other
evening, he commented on the poor judgement of teams like Phonak to ride
19mm tires during the TTT when Postal used "the fatest, ugliest tires we
could find." He said, "everyone knows that, in wet and rainy conditions,
you're more prone to flats and that's exactly what happened (to Phonak)."
(That's an approximate quote ... not an exact one.)

So the question is, why is this true? (And I know it is from personal
experience.) Why should a tire be more prone to a flat when the road is wet
than if it's dry? I can't come up with any logical reason that should be
true. I'd intuitively opt for larger tires in those conditions for a larger
contact patch and, hopefully, better handling in technical sections. But
what's up with flats in the wet?

Bob C.

Dear Bob,

In addition to the lubrication mentioned by other posters, a
wet front tire simply flips up far more sharp debris that
was lying harmlessly flat on the road and thus increases the
chances that the rear tire will be impaled.

Carl Fogel

In addition to those, I think the real reason is wet conditions allow small
pieces of debris to cling to the tire for a few more revolutions, thereby
having a better chance for a puncture. When it's wet, it's just stickier all
around.

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

psycholist said:

Watching The Lance Interview while spinning on the rollers the other
evening, he commented on the poor judgement of teams like Phonak to ride
19mm tires during the TTT when Postal used "the fatest, ugliest tires we
could find." He said, "everyone knows that, in wet and rainy conditions,
you're more prone to flats and that's exactly what happened (to Phonak)."
(That's an approximate quote ... not an exact one.)

So the question is, why is this true? (And I know it is from personal
experience.) Why should a tire be more prone to a flat when the road is

wet

Quoted message said:

Quoted message said:

than if it's dry? I can't come up with any logical reason that should be
true. I'd intuitively opt for larger tires in those conditions for a

larger

Quoted message said:

Quoted message said:

contact patch and, hopefully, better handling in technical sections. But
what's up with flats in the wet?

Bob C.

Dear Bob,

In addition to the lubrication mentioned by other posters, a
wet front tire simply flips up far more sharp debris that
was lying harmlessly flat on the road and thus increases the
chances that the rear tire will be impaled.

Carl Fogel

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Roger Moore said:

In addition to those, I think the real reason is wet conditions allow small
pieces of debris to cling to the tire for a few more revolutions, thereby
having a better chance for a puncture. When it's wet, it's just stickier all
around.

This falls in the "wiping tires" category of bicycle lore. I think
other respondents covered the reasons adequately. On the other hand,
skinny tires do about everything worse that a larger tire does within
reasonable sizes except weight, which has no bearing on a flat TT.

Jobst Brandt
[email hidden]

jobst brandt said:

Roger Moore said:

In addition to those, I think the real reason is wet conditions allow
small pieces of debris to cling to the tire for a few more revolutions,
thereby having a better chance for a puncture. When it's wet, it's just
stickier all around.

This falls in the "wiping tires" category of bicycle lore. I think
other respondents covered the reasons adequately. On the other hand,
skinny tires do about everything worse that a larger tire does within
reasonable sizes except weight, which has no bearing on a flat TT.

Just out of curiosity, where would you place the limit on "reasonable
sizes"?

--
Benjamin Lewis

TO ARMS! TO ARMS! Hooray! That's great
Two legs ain't bad unless there's a crate
They ship the parts to mama in. -- FZ

"Roger Moore" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

In addition to those, I think the real reason is wet conditions allow small
pieces of debris to cling to the tire for a few more revolutions, thereby
having a better chance for a puncture. When it's wet, it's just stickier all
around.

Don't let Jobst hear you say that. I agree with the FAQ, in that
water acts as a lubricant in cutting rubber. Try it for yourself with
a razor blade and an old tire.

Robin Hubert

Quoted message said:

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

psycholist said:

Watching The Lance Interview while spinning on the rollers the other
evening, he commented on the poor judgement of teams like Phonak to ride
19mm tires during the TTT when Postal used "the fatest, ugliest tires we
could find." He said, "everyone knows that, in wet and rainy conditions,
you're more prone to flats and that's exactly what happened (to Phonak)."
(That's an approximate quote ... not an exact one.)

So the question is, why is this true? (And I know it is from personal
experience.) Why should a tire be more prone to a flat when the road is

wet

Quoted message said:

Quoted message said:

than if it's dry? I can't come up with any logical reason that should be
true. I'd intuitively opt for larger tires in those conditions for a

larger

Quoted message said:

Quoted message said:

contact patch and, hopefully, better handling in technical sections. But
what's up with flats in the wet?

Bob C.

Dear Bob,

In addition to the lubrication mentioned by other posters, a
wet front tire simply flips up far more sharp debris that
was lying harmlessly flat on the road and thus increases the
chances that the rear tire will be impaled.

Carl Fogel

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Benjamin Lewis said:

Quoted message said:

Quoted message said:

In addition to those, I think the real reason is wet conditions
allow small pieces of debris to cling to the tire for a few more
revolutions, thereby having a better chance for a puncture. When
it's wet, it's just stickier all around.

Quoted message said:

Quoted message said:

This falls in the "wiping tires" category of bicycle lore. I think
other respondents covered the reasons adequately. On the other
hand, skinny tires do about everything worse that a larger tire
does within reasonable sizes except weight, which has no bearing on
a flat TT.

Quoted message said:

Just out of curiosity, where would you place the limit on
"reasonable sizes"?

In the days of yore when fashion had little affect on such things,
tubular tire manufacturers made mainly two sizes of tires for racing,
a 25mm for road and a 23mm for criteriums. I think the 25mm tire was
the culmination of much thought of the opposing demands. Before that,
on rough dirt roads 26 and 27mm tubulars existed but they went away as
pavement took over. Tire cross section is governed mainly by the
cushion required to keep the rim from hitting the road under
reasonable inflation (about 100psi).

Super slender tires (19mm) are being offered because there is a demand
for "something else" although they don't offer any advantages. It
took a long time for smooth tread to become standard (again) from the
days of tubulars of the pre WW2 era. Fashion and pseudo science, more
than ever, is running rampant in the bicycle business today.

See the resurgence of slots in saddles (from the 19th century) paired
spoke wheels (from the 19th century), sloping top tubes and curved
stays, all old hat but once again popular.

Jobst Brandt
[email hidden]

On Thu, 19 Aug 2004 20:35:51 GMT, [email hidden]

Quoted message said:

<SNIP>
In the days of yore when fashion had little affect on such things,
tubular tire manufacturers made mainly two sizes of tires for racing,
a 25mm for road and a 23mm for criteriums.
<SNIP>

Jobst Brandt
[email hidden]

If you'll pardon my ignorance, why the narrower tires for crits?

Matt.

jobst brandt said:

In the days of yore when fashion had little affect on such things,
tubular tire manufacturers made mainly two sizes of tires for racing,
a 25mm for road and a 23mm for criteriums. I think the 25mm tire was
the culmination of much thought of the opposing demands. Before that,
on rough dirt roads 26 and 27mm tubulars existed but they went away as
pavement took over. Tire cross section is governed mainly by the
cushion required to keep the rim from hitting the road under
reasonable inflation (about 100psi).

Super slender tires (19mm) are being offered because there is a demand
for "something else" although they don't offer any advantages. It
took a long time for smooth tread to become standard (again) from the
days of tubulars of the pre WW2 era. Fashion and pseudo science, more
than ever, is running rampant in the bicycle business today.

See the resurgence of slots in saddles (from the 19th century) paired
spoke wheels (from the 19th century), sloping top tubes and curved
stays, all old hat but once again popular.

Do you think there are any disadvantages to, say, 32mm tires, besides
possible clearance issues? I have a pair of completely slick tires of this
size on one of my bikes, and I like them a lot, albeit mainly for
unquantifiable reasons. In fact, my lowest ever 200 km ride time was on a
mountain bike frame with straight bars, and these tires (the amount of
drafting I did on that ride was the main reason for the time, however).

--
Benjamin Lewis

TO ARMS! TO ARMS! Hooray! That's great
Two legs ain't bad unless there's a crate
They ship the parts to mama in. -- FZ

Matthew C Roberts said:

Quoted message said:

In the days of yore when fashion had little affect on such things,
tubular tire manufacturers made mainly two sizes of tires for
racing, a 25mm for road and a 23mm for criteriums.

Quoted message said:

If you'll pardon my ignorance, why the narrower tires for crits?

Because they are held on smooth city streets. If the route does not
fit that description, road tires are in order. Of course this is not
considered by some riders and they get snake bite flats. On a road
race, you can encounter most anything.

Clement even had a road tire with the same casing as their Campionato
del Mundo road tire but with a narrower and thinner tread for a one
day classic called Paris-Roubaix.

Jobst Brandt
[email hidden]

Benjamin Lewis said:

Do you think there are any disadvantages to, say, 32mm tires,
besides possible clearance issues? I have a pair of completely
slick tires of this size on one of my bikes, and I like them a lot,
albeit mainly for unquantifiable reasons.

For me they have diminishing returns except when I ride on rough roads
where my speed is limited mainly by the size of rock I encounter who
how or soft the soil is. I have on occasion wished I could snap my
fingers and have my tires become 32's. If I were to ride a tandem,
that would be my choice.

Quoted message said:

In fact, my lowest ever 200 km ride time was on a mountain bike
frame with straight bars, and these tires (the amount of drafting I
did on that ride was the main reason for the time, however).

I don't think that is attributable to the fat tires but rather your
position on your bicycles and your energy level on that day.

Jobst Brandt
[email hidden]

jobst brandt said:

Benjamin Lewis said:

In fact, my lowest ever 200 km ride time was on a mountain bike
frame with straight bars, and these tires (the amount of drafting I
did on that ride was the main reason for the time, however).

I don't think that is attributable to the fat tires but rather your
position on your bicycles and your energy level on that day.

Certainly; I was merely indicating that they didn't prevent me from getting
a decent time, so any disadvantages they may have are not easily
observable by me. As I said, I attribute the time mainly to drafting (and
to the fact that I was hanging on for dear life to the wheel of someone who
promised me a lift home if I could keep up, and I didn't relish the idea of
50 km through mostly traffic after 200 km of lovely countryside)!

--
Benjamin Lewis

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

RE/

Quoted message said:

Clement even had a road tire with the same casing as...

How about another historical question?

Some old Brooks saddle catalogs refer to this or that saddle as a "Path" saddle.
Any idea what they're referring to?

e.g.
http://www.brooksarchives.info/brooks%20/catalogs/1914%20brooks/page8.html
--
Pete (Why Me?) Cresswell

Better e.g.
http://www.brooksarchives.info/brooks%20/catalogs/1914%20brooks/page10.html
--
Pete (Why Me?) Cresswell

On Thu, 19 Aug 2004 23:31:47 GMT, "(Pete Cresswell)" <[email hidden]>

Quoted message said:

RE/

Quoted message said:

Clement even had a road tire with the same casing as...

How about another historical question?

Some old Brooks saddle catalogs refer to this or that saddle as a "Path" saddle.
Any idea what they're referring to?

e.g.
http://www.brooksarchives.info/brooks%20/catalogs/1914%20brooks/page8.html

Dear Pete,

I see that the other models are called "road" models, so the
springier "path" saddle may have been for the adventurous
gentlemen who ventured off the main roads in that era and
rode on the more rugged footpaths.

I'm thinking mountain bikers wearing top hats.

Carl Fogel

[email hidden] wrote in message >

Quoted message said:

In addition to the lubrication mentioned by other posters, a
wet front tire simply flips up far more sharp debris that
was lying harmlessly flat on the road and thus increases the
chances that the rear tire will be impaled.

I'd have thought that would make a clear path for the rear tyre by throwing
it to the side, do you have any photographic evidence to support this? Are
you just repeating what others have said and will say?

Trevor

Benjamin Lewis wrote in message ...

Quoted message said:

jobst brandt said:

This falls in the "wiping tires" category of bicycle lore. I think
other respondents covered the reasons adequately. On the other hand,
skinny tires do about everything worse that a larger tire does within
reasonable sizes except weight, which has no bearing on a flat TT.

Just out of curiosity, where would you place the limit on "reasonable
sizes"?

That which is insignificantly more than something insignificantly less or
something insignificant like that or thereabouts. :-) Hate doing that.

Glass slivers do stick to the tyre and puncture miles later. In the dry the
slivers make shallow cuts and are usually flicked out effected by the
elastic properties of the rubber.

Trevor