Paul Sherwen: 70-80 psi!

Tubular tyres will work at much lower pressure than wired on tyres of
similar section.
The lower pressure maximises the length of contact patch with the road
ensuring directional stability in the wet. Specially important if using
bald tyres. Tubs can still be ridden as they are deflating(which is slower
than HP) and also when flat(presuming a good job has been made on gluing
them to the rim). It would help to know what tyre Sherwen thought he was
referring to.. I expect he was reminiscing. I have heard his commentaries
before.
TJ

Arthur Harris wrote in message ...

Quoted message said:

Since tire pressure seems to be a hot topic here on rbt lately, this should
be of interest.

Today's New York City Championship race is being covered by one of the

local

Quoted message said:

TV stations. Paul Sherwen is doing the announcing. In his commentary, he
explained that since the roads are wet, riders "who normally pump their
tires up to 110 psi will drop that down to 70 or 80 psi."

While I agree in principle with what he's saying, I can't believe that
riders would drop their pressure that much, especially on the roads of

lower

Quoted message said:

Manhattan.

Art Harris

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

Quoted message said:

Today's New York City Championship race is being covered by one of the local
TV stations. Paul Sherwen is doing the announcing. In his commentary, he
explained that since the roads are wet, riders "who normally pump their
tires up to 110 psi will drop that down to 70 or 80 psi."

Quoted message said:

While I agree in principle with what he's saying, I can't believe that
riders would drop their pressure that much, especially on the roads of lower
Manhattan.

Then there are those who do the opposite, pump their tires up to a higher
pressure when it rains. The idea being that the smaller contact patch
pushes water out of the way better.

Personally I tried both and neither seemed to make me feel faster or safer
in the rain.

Perhaps Mr. Brandt will chime in here.
--
Bruce Jackson - Sr. Systems Programmer - DMSP, a M/A/R/C Group company

Bruce Jackson said:

Then there are those who do the opposite, pump their tires up to a higher
pressure when it rains. The idea being that the smaller contact patch
pushes water out of the way better.

Those people are confused. Bike tires have no problem pushing water
out of the way, at any pressure. A wider tires makes sense on wet
pavement, though. Armstrong said they used the widest tires they had
on the team time trial, because of the wet pavement.

Quoted message said:

Perhaps Mr. Brandt will chime in here.

I'm pretty sure he's still pedaling around Europe.
--
terry morse Palo Alto, CA http://bike.terrymorse.com/

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

Quoted message said:

Those people are confused. Bike tires have no problem pushing water
out of the way, at any pressure. A wider tires makes sense on wet
pavement, though. Armstrong said they used the widest tires they had
on the team time trial, because of the wet pavement.

In the interview yesterday, I thought Lance said they (Team USPS) used heavy
wider tires in reguards to flats, during the TTT, unlike Team CSC who used
19mm tires and got many flats.
-tom

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

Quoted message said:

Bruce Jackson said:

Then there are those who do the opposite, pump their tires up to a higher
pressure when it rains. The idea being that the smaller contact patch
pushes water out of the way better.

Those people are confused. Bike tires have no problem pushing water
out of the way, at any pressure. A wider tires makes sense on wet
pavement, though. Armstrong said they used the widest tires they had
on the team time trial, because of the wet pavement.

Quoted message said:

Perhaps Mr. Brandt will chime in here.

I'm pretty sure he's still pedaling around Europe.

Actually, he said they ran big tires because of flats, not the rain
itself. Exactly how rain causes flats, I'm not sure, and he didn't
elaborate. ;->

[email hidden] (Scott Hendricks) wrote:
<< Actually, he said they ran big tires because of flats, not the rain
itself. Exactly how rain causes flats, I'm not sure, and he didn't
elaborate. ;-> >>

Sherwen often suggests that tires are more prone to punctures in the rain. The
assumption is that rain loosens cinders and other sharp debris that is normally
more imbedded in the road surface, making it more likely to be picked up in the
tire tread. How fatter tires would help avoid this, I do not know.

Scott Hendricks said:

Actually, he said they ran big tires because of flats, not the rain
itself. Exactly how rain causes flats, I'm not sure, and he didn't
elaborate. ;->

Rain makes flats more likely for two reasons: bits of glass and other
sharp things are more likely to be picked up by a wet tire, giving it
several revolutions to find its way in, and the cutting edge is lubricated
by the water, making it easier to cut.

Worst part of this, for us mere mortals who don't have a team car
following, is that finding the bit of glass that caused the flat, or (wore
yet) patching a tube, is much harder in the rain. Best idea is to carry a
spare tire, not just a couple of tubes, for wet flat repair.

--

David L. Johnson

__o | Do not worry about your difficulties in mathematics, I can
_`\(,_ | assure you that mine are all greater. -- A. Einstein
(_)/ (_) |

Tom Nakashima said:

Terry Morse said:

Those people are confused. Bike tires have no problem pushing water
out of the way, at any pressure. A wider tires makes sense on wet
pavement, though. Armstrong said they used the widest tires they had
on the team time trial, because of the wet pavement.

In the interview yesterday, I thought Lance said they (Team USPS) used heavy
wider tires in reguards to flats, during the TTT, unlike Team CSC who used
19mm tires and got many flats.

I seem to recall him mentioning flats as an afterthought, but I
didn't infer that he meant the wider tires were meant to prevent
flats. That doesn't make sense. Wider tires reduce the chance of
sliding out in the wet, but I can't see how wide tires would reduce
the chance of flats.
--
terry morse Palo Alto, CA http://bike.terrymorse.com/

Scott Hendricks said:

Exactly how rain causes flats, I'm not sure, and he didn't
elaborate. ;->

Lance probably doesn't know why.

Water acts as a lubricant, making it much easier to cut through the
rubber. It seems to me that rain also moves around lots of crud on
the road that was peacefully just sitting there before, not causing
anyone any trouble. Some of that crud is sharp enough to cause a
puncture. I tend to get flats in the rain from the tiniest pieces of
glass, so small they're often hard to find in the tire.
--
terry morse Palo Alto, CA http://bike.terrymorse.com/

On 2 Aug 2004 11:07:30 -0700, [email hidden]

(Scott Hendricks) said:

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

Quoted message said:

Bruce Jackson said:

Then there are those who do the opposite, pump their tires up to a higher
pressure when it rains. The idea being that the smaller contact patch
pushes water out of the way better.

Those people are confused. Bike tires have no problem pushing water
out of the way, at any pressure. A wider tires makes sense on wet
pavement, though. Armstrong said they used the widest tires they had
on the team time trial, because of the wet pavement.

Quoted message said:

Perhaps Mr. Brandt will chime in here.

I'm pretty sure he's still pedaling around Europe.

Actually, he said they ran big tires because of flats, not the rain
itself. Exactly how rain causes flats, I'm not sure, and he didn't
elaborate. ;->

Dear Scott,

As others have mentioned, water lubricates the blade, so to
speak, allowing it to penetrate the tire more easily.

Water also provides more blades to skewer tires.

Most sharp debris (think of a nail) lies flat on the road,
so both tires can roll over it unharmed.

However, the debris may bounce up when the front tire rolls
briskly over it and then be in just the right position to
impale the rear tire. This is why rear flats are more
common.

Wet tires increase the likelihood of this mishap because
they throw up far more debris that would otherwise lie
undisturbed.

Carl Fogel

Terry Morse said:

Tom Nakashima wrote:

Quoted message said:

Quoted message said:

In the interview yesterday, I thought Lance said they (Team USPS) used heavy
wider tires in reguards to flats, during the TTT, unlike Team CSC who used
19mm tires and got many flats.

Quoted message said:

I seem to recall him mentioning flats as an afterthought, but I
didn't infer that he meant the wider tires were meant to prevent
flats. That doesn't make sense. Wider tires reduce the chance of
sliding out in the wet, but I can't see how wide tires would reduce
the chance of flats.

He said "fattest heaviest tires" or something like that. As opposed
to Phonak (not CSC) who used 19mm wide track or TT tubulars.

Maybe tire width doesn't have a theoretical relation to flat
frequency, but practically speaking, among the tires that are
actually available, fatter tires are heavier and have thicker
rubber, hence more flat resistance. Especially when compared
to 19mm TT tires. So practically speaking, Armstrong was correct.

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Scott Hendricks said:

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

Quoted message said:

Bruce Jackson said:

Then there are those who do the opposite, pump their tires up to a higher
pressure when it rains. The idea being that the smaller contact patch
pushes water out of the way better.

Those people are confused. Bike tires have no problem pushing water
out of the way, at any pressure. A wider tires makes sense on wet
pavement, though. Armstrong said they used the widest tires they had
on the team time trial, because of the wet pavement.

Quoted message said:

Perhaps Mr. Brandt will chime in here.

I'm pretty sure he's still pedaling around Europe.

Actually, he said they ran big tires because of flats, not the rain
itself. Exactly how rain causes flats, I'm not sure, and he didn't
elaborate. ;->

I notice the commuting I often get more flats in the rain when running
smaller than 700x28 tires. Mainly, I figure, as I am paying more
attention to the water streaming down my legs into my socks and into my
eyes than I am avoiding those small bits and pieces that typically cause
flats. I attribute the reliability of the larger tires more to the
thicker rubber on those tires than to any inherent advantage of the
width- though that may be a factor in some way.

On 2 Aug 2004 11:07:30 -0700, [email hidden] (Scott

Hendricks) said:

Actually, he said they ran big tires because of flats, not the rain
itself. Exactly how rain causes flats, I'm not sure, and he didn't
elaborate. ;->

Water acts as a lubricant, allowing little bits of glass and other
things to slide more easily through the tread and casing.

JT

Mike Krueger wrote in message
<[email hidden]>...

Quoted message said:

Sherwen often suggests that tires are more prone to punctures in the rain.

The

Quoted message said:

assumption is that rain loosens cinders and other sharp debris that is

normally

Quoted message said:

more imbedded in the road surface, making it more likely to be picked up in

the

Quoted message said:

tire tread. How fatter tires would help avoid this, I do not know.

Lower usable tyre pressure means less force is available for impaler to do
its dirty work.
TJ

Justin Seiferth <[email hidden]> wrote:

: [...] Mainly, I figure, as I am paying more
: attention to the water streaming down my legs into my socks and into my
: eyes [...]

You riding some kind of weird recumbent?

- mark

Mark Vieselmeyer said:

Justin Seiferth <[email hidden]> wrote:

: [...] Mainly, I figure, as I am paying more
: attention to the water streaming down my legs into my socks and into my
: eyes [...]

You riding some kind of weird recumbent?

I thought that the weird bicycles were those that imitate a horseback
riding position.

--
Tom Sherman – Quad City Area