tire pressure for slippery pavement

Mike Jacoubowsky said:

This morning's regular Tuesday/Thursday-morning ride was memorable due to
some unexpected, and *very* slippery pavement. The fog had burned off some
time earlier, but there was something about what it left behind in a few
places that caused noticeable slipping (a bit of an uncomfortable feeling as
you're going through a corner in a downhill spint!).

One of the guys decided, at the top of one of the climbs, to let some air
out of his tires. And he was the only person who, in a corner that didn't
look all that bad, went down (hard).

Personally, I haven't found much benefit to reducing the air in my tires
when things are wet; wider tires, on the other hand, have made a noticeable
improvement (I run 23c normally, and 25c in the winter).

But what do the traction experts say about reducing air when things are wet?
Does it actually help? And if so, how much do you reduce the pressure? Is
there a point where you have too little air and the effect is reversed (less
traction & control instead of more)?

Interesting.

I am lazy and sometimes end up with only 60 psi left in my tires, but I
ride tubulars so maybe it doesn't matter as much.

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

Quoted message said:

This morning's regular Tuesday/Thursday-morning ride was

memorable due to

Quoted message said:

some unexpected, and *very* slippery pavement. The fog had

burned off some

Quoted message said:

time earlier, but there was something about what it left behind

in a few

Quoted message said:

places that caused noticeable slipping (a bit of an

uncomfortable feeling as

Quoted message said:

you're going through a corner in a downhill spint!).

One of the guys decided, at the top of one of the climbs, to

let some air

Quoted message said:

out of his tires. And he was the only person who, in a corner

that didn't

Quoted message said:

look all that bad, went down (hard).

Personally, I haven't found much benefit to reducing the air in

my tires

Quoted message said:

when things are wet; wider tires, on the other hand, have made

a noticeable

Quoted message said:

improvement (I run 23c normally, and 25c in the winter).

But what do the traction experts say about reducing air when

things are wet?

Quoted message said:

Does it actually help? And if so, how much do you reduce the

pressure? Is

Quoted message said:

there a point where you have too little air and the effect is

reversed (less

Quoted message said:

traction & control instead of more)?

Ooooh, fog. That must be tough. I rode to work in a monsoon
with miles of standing water (flood warnings in effect) and piles
of fallen leaves. I was running 25mm Contis with about 90psi and
remained upright -- although no tire or inflation pressure would
have saved me from slipping out on a wet, leafy corner. I just
go slower, particularly when I hit the lakes. (Kudos to my
Performance neoprene booties, which were practically submurged
and still kept my feet reasonably dry.)

Anyway, as you know from your abundant experience, there is a
magical place between maximum inflation and flat where you get
better wet traction because there is a larger contact patch. I
think it is around 20lbs below maximum inflation with my Contis.
Somewhere below that, you get squirm and bad traction. You
should get a leaky tube and go do some research. I did this
involuntarily (sort of) while riding the banks at the Alpenrose
velodrome at a pretty consistent speed on a rear tire with a slow
leak. It got down to "pretty soft but rideable" before it
slipped out. IMO, wet traction has much more to do with with
width and tread compound than letting a few pounds out of the
tire. -- Jay Beattie.

In article
<[email hidden]>,

Mike Jacoubowsky said:

This morning's regular Tuesday/Thursday-morning ride was memorable due to
some unexpected, and *very* slippery pavement. The fog had burned off some
time earlier, but there was something about what it left behind in a few
places that caused noticeable slipping (a bit of an uncomfortable feeling as
you're going through a corner in a downhill spint!).

One of the guys decided, at the top of one of the climbs, to let some air
out of his tires. And he was the only person who, in a corner that didn't
look all that bad, went down (hard).

Personally, I haven't found much benefit to reducing the air in my tires
when things are wet; wider tires, on the other hand, have made a noticeable
improvement (I run 23c normally, and 25c in the winter).

But what do the traction experts say about reducing air when things are wet?
Does it actually help? And if so, how much do you reduce the pressure? Is
there a point where you have too little air and the effect is reversed (less
traction & control instead of more)?

Could be he got over-confident and cooked the turn.

I can tell if the pressure in a tire is down by the way
it corners. Even a low rear tire is squirrely in a
tight turn. I think that standard pressure for the tire
is best for precise handling.

--
Michael Press

Quoted message said:

Quoted message said:

But what do the traction experts say about reducing air when things are
wet?
Does it actually help? And if so, how much do you reduce the pressure? Is
there a point where you have too little air and the effect is reversed
(less
traction & control instead of more)?

Could be he got over-confident and cooked the turn.

Or could be that he was trying to get whatever advantage possible setting up
the Albion sprint on our Tuesday/Thursday-morning ride. Not so much
over-confident as putting a bit too much power into a corner that I'm
happier coasting through due to inverted banking, a bit of gravel and some
tar stripes (the latter probably being what did him in).

Quoted message said:

I can tell if the pressure in a tire is down by the way
it corners. Even a low rear tire is squirrely in a
tight turn. I think that standard pressure for the tire
is best for precise handling.

I'm with you on that one; I keep the same tire pressure wet or dry, choosing
instead to go to a wider tire when wet. I just don't like the way tires feel
when they're even slightly underinflated, but that's just me. I think if I
*always* rode at 100psi instead of 120, I'd get used to it and they'd feel
fine.

But there's still a curve regarding traction vs tire pressure for any given
tire. Obviously there's a too-much-pressure point where traction diminishes.
And, I *think*, there's a point where too-little pressure causes reduced
traction as well. Or is it that traction isn't reduced per se, but rather
that handling changes so much that it's no longer stable, regardless of
"traction?"

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

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

Quoted message said:

In article
<[email hidden]>,

Mike Jacoubowsky said:

This morning's regular Tuesday/Thursday-morning ride was memorable due to
some unexpected, and *very* slippery pavement. The fog had burned off
some
time earlier, but there was something about what it left behind in a few
places that caused noticeable slipping (a bit of an uncomfortable feeling
as
you're going through a corner in a downhill spint!).

One of the guys decided, at the top of one of the climbs, to let some air
out of his tires. And he was the only person who, in a corner that didn't
look all that bad, went down (hard).

Personally, I haven't found much benefit to reducing the air in my tires
when things are wet; wider tires, on the other hand, have made a
noticeable
improvement (I run 23c normally, and 25c in the winter).

But what do the traction experts say about reducing air when things are
wet?
Does it actually help? And if so, how much do you reduce the pressure? Is
there a point where you have too little air and the effect is reversed
(less
traction & control instead of more)?

Could be he got over-confident and cooked the turn.

I can tell if the pressure in a tire is down by the way
it corners. Even a low rear tire is squirrely in a
tight turn. I think that standard pressure for the tire
is best for precise handling.

--
Michael Press

Mike Jacoubowsky said:

This morning's regular Tuesday/Thursday-morning ride was memorable due to
some unexpected, and *very* slippery pavement. The fog had burned off some
time earlier, but there was something about what it left behind in a few
places that caused noticeable slipping (a bit of an uncomfortable feeling as
you're going through a corner in a downhill spint!).

One of the guys decided, at the top of one of the climbs, to let some air
out of his tires. And he was the only person who, in a corner that didn't
look all that bad, went down (hard).

Personally, I haven't found much benefit to reducing the air in my tires
when things are wet; wider tires, on the other hand, have made a noticeable
improvement (I run 23c normally, and 25c in the winter).

But what do the traction experts say about reducing air when things are wet?
Does it actually help? And if so, how much do you reduce the pressure? Is
there a point where you have too little air and the effect is reversed (less
traction & control instead of more)?

Thanks-

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Dear Mike,

One crash in one corner isn't much data.

The rider who fell may have simply screwed up, been betrayed by
different tires, hit a different spot on the road, or been riding
slightly faster because he thought lower pressures would help.

But you can google for the obvious terms:

http://www.google.com/search?q=traction+%22tire+inflation%22+cornering+lower&hl=en&lr=&as_qdr=all&start=10&sa=N

I don't think that you'll find anything except comments that
underinflation is bad for braking, acceleration, steering precision,
and cornering stability.

Cheers,

Carl Fogel

Quoted message said:

Mike Jacoubowsky said:

This morning's regular Tuesday/Thursday-morning ride was memorable due to
some unexpected, and *very* slippery pavement. The fog had burned off some
time earlier, but there was something about what it left behind in a few
places that caused noticeable slipping (a bit of an uncomfortable feeling as
you're going through a corner in a downhill spint!).

One of the guys decided, at the top of one of the climbs, to let some air
out of his tires. And he was the only person who, in a corner that didn't
look all that bad, went down (hard).

Personally, I haven't found much benefit to reducing the air in my tires
when things are wet; wider tires, on the other hand, have made a noticeable
improvement (I run 23c normally, and 25c in the winter).

But what do the traction experts say about reducing air when things are wet?
Does it actually help? And if so, how much do you reduce the pressure? Is
there a point where you have too little air and the effect is reversed (less
traction & control instead of more)?

Thanks-

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Dear Mike,

One crash in one corner isn't much data.

The rider who fell may have simply screwed up, been betrayed by
different tires, hit a different spot on the road, or been riding
slightly faster because he thought lower pressures would help.

But you can google for the obvious terms:

http://www.google.com/search?q=traction+%22tire+inflation%22+cornering+lower&hl=en&lr=&as_qdr=all&start=10&sa=N

I don't think that you'll find anything except comments that
underinflation is bad for braking, acceleration, steering precision,
and cornering stability.

Cheers,

Carl Fogel

Here's an extensive study of the effect of various tire inflation
levels on car tires for braking on wet and dry surfaces and for the
coefficient of friction:

http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS-FMVSS-No138-2005/part2.html

Briefly, cars do worse as tire pressure drops. You can find some
exceptions, but the overwhelming trend is that lower pressures aren't
helping.

CF

Quoted message said:

Here's an extensive study of the effect of various tire inflation
levels on car tires for braking on wet and dry surfaces and for the
coefficient of friction:

http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS-FMVSS-No138-2005/part2.html

Briefly, cars do worse as tire pressure drops. You can find some
exceptions, but the overwhelming trend is that lower pressures aren't
helping.

But bicycle tires are quite different from car tires, which are designed to
be "flat" on the road. I don't think reducing pressure would make a tire
more "flat" (increase surface area/contact patch) than it already is. More
likely you'll just get a bulging sidewall.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
<[email hidden]> wrote in message

news:[email hidden]...

Quoted message said:

Quoted message said:

Mike Jacoubowsky said:

This morning's regular Tuesday/Thursday-morning ride was memorable due to
some unexpected, and *very* slippery pavement. The fog had burned off
some
time earlier, but there was something about what it left behind in a few
places that caused noticeable slipping (a bit of an uncomfortable feeling
as
you're going through a corner in a downhill spint!).

One of the guys decided, at the top of one of the climbs, to let some air
out of his tires. And he was the only person who, in a corner that didn't
look all that bad, went down (hard).

Personally, I haven't found much benefit to reducing the air in my tires
when things are wet; wider tires, on the other hand, have made a
noticeable
improvement (I run 23c normally, and 25c in the winter).

But what do the traction experts say about reducing air when things are
wet?
Does it actually help? And if so, how much do you reduce the pressure? Is
there a point where you have too little air and the effect is reversed
(less
traction & control instead of more)?

Thanks-

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Dear Mike,

One crash in one corner isn't much data.

The rider who fell may have simply screwed up, been betrayed by
different tires, hit a different spot on the road, or been riding
slightly faster because he thought lower pressures would help.

But you can google for the obvious terms:

http://www.google.com/search?q=traction+%22tire+inflation%22+cornering+lower&hl=en&lr=&as_qdr=all&start=10&sa=N

I don't think that you'll find anything except comments that
underinflation is bad for braking, acceleration, steering precision,
and cornering stability.

Cheers,

Carl Fogel

Here's an extensive study of the effect of various tire inflation
levels on car tires for braking on wet and dry surfaces and for the
coefficient of friction:

http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS-FMVSS-No138-2005/part2.html

Briefly, cars do worse as tire pressure drops. You can find some
exceptions, but the overwhelming trend is that lower pressures aren't
helping.

CF

Mike Jacoubowsky said:

Quoted message said:

Here's an extensive study of the effect of various tire inflation
levels on car tires for braking on wet and dry surfaces and for the
coefficient of friction:

http://www.nhtsa.dot.gov/cars/rules/rulings/TPMS-FMVSS-No138-2005/part2.html

Briefly, cars do worse as tire pressure drops. You can find some
exceptions, but the overwhelming trend is that lower pressures aren't
helping.

But bicycle tires are quite different from car tires, which are designed to
be "flat" on the road. I don't think reducing pressure would make a tire
more "flat" (increase surface area/contact patch) than it already is. More
likely you'll just get a bulging sidewall.

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Dear Mike,

Bicycle tires are indeed different from car tires.

But both kinds of tires press flat against the flat road surface.

The tube-shaped bicycle tire expands its contact patch both sideways
and lengthwise.

[censored] becomes XXXXXX, longer and wider

The car tire doesn't put more tread on the ground to either side, but
it does expand lengthwise.

XX becomes [censored], longer but not wider

In both cases, lower pressures increase the contact patch area.

Cheers,

Carl Fogel

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

Quoted message said:

This morning's regular Tuesday/Thursday-morning ride was memorable due

to

Quoted message said:

some unexpected, and *very* slippery pavement. The fog had burned off

some

Quoted message said:

time earlier, but there was something about what it left behind in a

few

Quoted message said:

places that caused noticeable slipping (a bit of an uncomfortable

feeling as

Quoted message said:

you're going through a corner in a downhill spint!).

One of the guys decided, at the top of one of the climbs, to let some

air

Quoted message said:

out of his tires. And he was the only person who, in a corner that

didn't

Quoted message said:

look all that bad, went down (hard).

Personally, I haven't found much benefit to reducing the air in my

tires

Quoted message said:

when things are wet; wider tires, on the other hand, have made a

noticeable

Quoted message said:

improvement (I run 23c normally, and 25c in the winter).

But what do the traction experts say about reducing air when things

are wet?

Quoted message said:

Does it actually help? And if so, how much do you reduce the pressure?

Is

Quoted message said:

there a point where you have too little air and the effect is reversed

(less

Quoted message said:

traction & control instead of more)?

Thanks-

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA

Tire tread pattern can make a big difference in corning especially wet
versus dry conditions. A lot the currently available tires have a hard
narrow center rib and not much pattern on either side for gripping in
corners.

Chas.

* * Chas said:

...
Tire tread pattern can make a big difference in corning especially wet
versus dry conditions. A lot the currently available tires have a hard
narrow center rib and not much pattern on either side for gripping in
corners.

Since the rubber in a tire tread is much softer than the pavement
surface, it will conform to minor irregularities. Patterned tread will
only decrease the contact area between the tire and pavement.

Bicycle tires are narrow enough and have high enough inflation
pressures that hydroplaning will not occur under real world conditions,
so channels in the tread to remove water from between the tire and
pavement are not needed.

--
Tom Sherman - Post Free or Die!

Johnny Sunset said:

* * Chas said:

...
Tire tread pattern can make a big difference in corning especially wet
versus dry conditions. A lot the currently available tires have a hard
narrow center rib and not much pattern on either side for gripping in
corners.

Since the rubber in a tire tread is much softer than the pavement
surface, it will conform to minor irregularities. Patterned tread will
only decrease the contact area between the tire and pavement.

Bicycle tires are narrow enough and have high enough inflation
pressures that hydroplaning will not occur under real world conditions,
so channels in the tread to remove water from between the tire and
pavement are not needed.

it's not inflation pressure that prevents hydroplaning, it's the load on
the tire per its contact area. bike tires are up near 100psi contact
pressure, enough to disperse water in the contact patch. that pressure
cannot however disperse mud and debris that washes onto roads, in which
case the cogging action of a tread pattern may be of advantage.

* * Chas said:

A lot the currently available tires have a hard
narrow center rib and not much pattern on
either side for gripping in
corners.

What road tires have a center rib? I use mainly racing tires
(Vittoria, Schwalbe, Michelin, Continental) and haven't see that for
years.
--
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************

jim beam said:

Johnny Sunset said:

* * Chas said:

...
Tire tread pattern can make a big difference in corning especially wet
versus dry conditions. A lot the currently available tires have a hard
narrow center rib and not much pattern on either side for gripping in
corners.

Since the rubber in a tire tread is much softer than the pavement
surface, it will conform to minor irregularities. Patterned tread will
only decrease the contact area between the tire and pavement.

Bicycle tires are narrow enough and have high enough inflation
pressures that hydroplaning will not occur under real world conditions,
so channels in the tread to remove water from between the tire and
pavement are not needed.

it's not inflation pressure that prevents hydroplaning, it's the load on
the tire per its contact area.

Which is merely another way of saying what I wrote above, since with
flexible bicycle tire casings, contact pressure will depend on
inflation pressure.

Quoted message said:

bike tires are up near 100psi contact
pressure, enough to disperse water in the contact patch. that pressure
cannot however disperse mud and debris that washes onto roads, in which
case the cogging action of a tread pattern may be of advantage.

Does the "herringbone" tread pattern found on many road tires really do
anything in this situation?

--
Tom Sherman - Post Free or Die!

Mike Jacoubowsky said:

This morning's regular Tuesday/Thursday-morning ride was memorable due to
some unexpected, and *very* slippery pavement. The fog had burned off some
time earlier, but there was something about what it left behind in a few
places that caused noticeable slipping (a bit of an uncomfortable feeling as
you're going through a corner in a downhill spint!).

No idea about the original request. Just a word of caution. If you'll ever
ride in France under wet conditions (rain, fog) avoid all road markings,
zebra crossing included. They get as slippery as if they were covered in
soap. The worse are the zebra crossing at the entry/exit from roundabouts,
where leaning is unavoidable. One moment you are up and the next moment
you ask yourself who knocked you over.

Ciao,
--
Roberto Divia` Love at first sight is one of the greatest
Dep:PH Bat:53 Mailbox:C02110 labour-saving devices the world has ever seen
Route de Meyrin 385 ---------------------------------------------
Case Postale Phone: +41-22-767-4994
CH-1211 Geneve 23 CERN Fax: +41-22-767-9585
Switzerland E-Mail: [email hidden]

Johnny Sunset said:

jim beam said:

Johnny Sunset said:

* * Chas wrote:
> ...
> Tire tread pattern can make a big difference in corning especially wet
> versus dry conditions. A lot the currently available tires have a hard
> narrow center rib and not much pattern on either side for gripping in
> corners.
Since the rubber in a tire tread is much softer than the pavement
surface, it will conform to minor irregularities. Patterned tread will
only decrease the contact area between the tire and pavement.

Bicycle tires are narrow enough and have high enough inflation
pressures that hydroplaning will not occur under real world conditions,
so channels in the tread to remove water from between the tire and
pavement are not needed.

it's not inflation pressure that prevents hydroplaning, it's the load on
the tire per its contact area.

Which is merely another way of saying what I wrote above, since with
flexible bicycle tire casings, contact pressure will depend on
inflation pressure.

so if the contact area was 3 square inches not 1 and the inflation
pressure was still 100lbs, what would the contact pressure be then?

Quoted message said:

Quoted message said:

bike tires are up near 100psi contact
pressure, enough to disperse water in the contact patch. that pressure
cannot however disperse mud and debris that washes onto roads, in which
case the cogging action of a tread pattern may be of advantage.

Does the "herringbone" tread pattern found on many road tires really do
anything in this situation?

do you bother to do your own homework or do you just repeat what others
tell you?

Roberto Divia said:

No idea about the original request. Just a word of caution. If you'll ever
ride in France under wet conditions (rain, fog) avoid all road markings,
zebra crossing included. They get as slippery as if they were covered in
soap. The worse are the zebra crossing at the entry/exit from roundabouts,
where leaning is unavoidable. One moment you are up and the next moment
you ask yourself who knocked you over.

We have some of the same sort of hazardous stripes here in the USA too.
Very scary!

Chas who? said:

Quoted message said:

This morning's regular Tuesday/Thursday-morning ride was memorable
due to some unexpected, and *very* slippery pavement. The fog had
burned off some time earlier, but there was something about what it
left behind in a few places that caused noticeable slipping (a bit
of an uncomfortable feeling as you're going through a corner in a
downhill sprint!).

Quoted message said:

Quoted message said:

One of the guys decided, at the top of one of the climbs, to let
some air out of his tires. And he was the only person who, in a
corner that didn't look all that bad, went down (hard).

Quoted message said:

Quoted message said:

Personally, I haven't found much benefit to reducing the air in my
tires when things are wet; wider tires, on the other hand, have
made a noticeable improvement (I run 23c normally, and 25c in the
winter).

Quoted message said:

Quoted message said:

But what do the traction experts say about reducing air when things
are wet? Does it actually help? And if so, how much do you reduce
the pressure? Is there a point where you have too little air and
the effect is reversed (less traction & control instead of more)?

Quoted message said:

Tire tread pattern can make a big difference in corning especially
wet versus dry conditions. A lot the currently available tires have
a hard narrow center rib and not much pattern on either side for
gripping in corners.

Would you care to explain what "tread pattern" does for wet traction
on pavement? While you're at it, consider that motorcycle and
aircraft tires are slick and travel as much as ten times as fast in
downpours as a cornering bicycle.

http://draco.acs.uci.edu/rbfaq/FAQ/8b.13.html

Jobst Brandt

Roberto Divia said:

Quoted message said:

This morning's regular Tuesday/Thursday-morning ride was memorable
due to some unexpected, and *very* slippery pavement. The fog had
burned off some time earlier, but there was something about what it
left behind in a few places that caused noticeable slipping (a bit
of an uncomfortable feeling as you're going through a corner in a
downhill sprint!).

Quoted message said:

No idea about the original request. Just a word of caution. If
you'll ever ride in France under wet conditions (rain, fog) avoid
all road markings, zebra crossing included. They get as slippery as
if they were covered in soap. The worse are the zebra crossing at
the entry/exit from roundabouts, where leaning is unavoidable. One
moment you are up and the next moment you ask yourself who knocked
you over.

Painted and epoxy applique striping on most roads are slick when wet.
Traction arises from the fine grain structure of the grains of sand of
which it is made and paint does not have that. Most basalt paving
stones are super slick when wet because they are homogeneous and
polish to nearly optically smooth surfaces. Fortunately we don't see
many of these anymore. ("Kopfstein Pflaster" as they were known in
German speaking areas).

Shiny black tar fillers of pavement cracks are also slick when wet
unless they given a sand dusting when made. I have seen bicyclists
fall on tar stripes when climbing.

Jobst Brandt

Mike Jacoubowsky said:

This morning's regular Tuesday/Thursday-morning ride was memorable due to
some unexpected, and *very* slippery pavement. The fog had burned off some
time earlier, but there was something about what it left behind in a few
places that caused noticeable slipping (a bit of an uncomfortable feeling as
you're going through a corner in a downhill spint!).

Road slime. Oil residue mixed with dust and moisture; it's like
gritty grease. That's the deadly combination that makes driving
particularly hazardous for a few minutes when a thunderstorm hits a
stretch of road that hasn't been washed clean in several weeks. It
can get as slick as ice. The common miswisdom is often that "people
forget how to drive on wet roads", but really the problem is that the
freshly dampened road surface is just extra treacherous. In your
case, a lack of traffic had left just enough of the condensed moisture
on the road to do the trick.

Quoted message said:

One of the guys decided, at the top of one of the climbs, to let some air
out of his tires.

Bad move.

Quoted message said:

And he was the only person who, in a corner that didn't
look all that bad, went down (hard).

An unfortunate way to get an education.

Quoted message said:

Personally, I haven't found much benefit to reducing the air in my tires
when things are wet;

There's a different between wet and lubricated.

Quoted message said:

wider tires, on the other hand, have made a noticeable
improvement (I run 23c normally, and 25c in the winter).

Much may depend on the compound as well.

Quoted message said:

But what do the traction experts say about reducing air when things are wet?

In merely *wet* conditions, you won't get a bike tire past the speed
at which aquaplaning is a hazard, so a larger contact patch could give
a better grip. However, this is reversed in the conditions you
encountered because it's not just wet but lubricated with agents
beyond mere water. Less air pressure = more contact patch = lower
force pushing tire against pavement. If the problem is a lubricated
surface, you want the highest contact pressure you can get.

Reducing tire pressure is generally not a wet-surface tactic anyway,
it's a soft-surface technique, but its utility on a roadie (or even on
an mb, for that matter) is probably minimal. If the surface is soft
enough that a larger contact patch is needed, you're not going to make
enough difference by lowering the pressure in a bike tire; there's not
enough gain possible. This is a useful gambit on large tires, though,
such as on powered equipment that must traverse soft sand.

OTOH, if the surface is hard and relatively smooth but slippery due to
oily crud, the larger contact patch is *worse* than the smaller one.

Quoted message said:

Does it actually help?

Quite the opposite in the conditions you described.

Quoted message said:

And if so, how much do you reduce the pressure?

Negatively, if possible, in this case.

Quoted message said:

Is
there a point where you have too little air and the effect is reversed (less
traction & control instead of more)?

In the described conditions, any pressure reduction has the potential
to reduce the traction to the spill point. Don't do it.

In the wet, I doubt that it will make enough difference to be worth
the added risk of pinch flats. I wouldn't do it there, either. Your
employment of a slightly larger tire in wet weather is the better
choice IMO.

--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.