Re: Tire Thread Count - What difference does it make?

RE/

Quoted message said:

I assume the weight goes into the casing. Right now
I own some IRC triathlon with kevlar belts with 120 tpi, and some
victoria action tires with 66 tpi. They weigh close to 300 grams. I
can't tell any difference.

Maybe its different for skinny high pressure tires.

I run 55/55 tires at about 35 psi. The ones I like best are 130 tpi WTB Mutano
Raptors. I've got another set that are 60 tpi (Heng Shin SemiSlicks).

The 130 tpi tires seem to roll a *lot* easier than the 60's - even on a paved
surface - and the 130's have a lot more tread on them.

OTOH, I'm one of those people who will swear that their car runs better after
being washed...so maybe my comparison isn't very scientific either...
--
PeteCresswell

Pete Cresswell said:

Quoted message said:

I assume the weight goes into the casing. Right now I own some IRC
triathlon with Kevlar belts with 120 TPI, and some Vittoria action
tires with 66 TPI. They weigh close to 300 grams. I can't tell any
difference.

Quoted message said:

Maybe its different for skinny high pressure tires.

Quoted message said:

I run 55/55 tires at about 35 psi. The ones I like best are 130 TPI
WTB Mutano Raptors. I've got another set that are 60 TPI (Heng Shin
SemiSlicks).

Kevlar is notorious for bad RR in tire casings and I'm not aware that
anyone is making a Kevlar tire , only Kevlar inlays as a belt under
the tread. Even these produce measurably poorer RR and that is why
they are so uselessly thin. They won't stop thorns either just as a
sewing needle will easily go through a bullet proof vest.

Quoted message said:

The 130 TPI tires seem to roll a *lot* easier than the 60's - even
on a paved surface - and the 130's have a lot more tread on them.

Quoted message said:

OTOH, I'm one of those people who will swear that their car runs
better after being washed...so maybe my comparison isn't very
scientific either...

That's a good survey not to be ignored. Just ask the guy in his
freshly washed and waxed car if it doesn't feel a lot better.

Jobst Brandt
[email hidden]

[email hidden] (andres muro) wrote in message news:<[email hidden]>...

Quoted message said:

I own tires with 120 count and with 66 thread count. I really can't
tell the difference. Also, I usually get about the same amount of
flats with both. When I buy a tire, I try to go for weight and price.
I hate to pay anything more than 12.00 bucks, so I look for sales.

I'm with you. Seems like there's a well-regarded tire on sale for
a great price often enough at either nasbar or performance that if
I buy four of them, I'm good until the next good deal comes along.

Right now I'm riding Panaracer Stradius Elites, which I think feel
stickier but also heavier and not quite as free-rolling than the
last sale tire I tried which was Michelin Hi-Lite Prestige. Gonna
order some of the $13 Conti 3000s on sale at performance right now.

I think Mike J said recently that people usually stick with whatever
came on their bike. Definately true of me. All I rode for the first
five years was Conti 2000s. I am now enjoying trying out different
tires -- but although it's fun and interesting, I have not yet found
any reason not to go back to the 2000s, which are nice and light and
always 20 bucks. Except possibly:
- Either it's my imagination or they slice on glass even more than
other tires (maybe just due to thin tread/light weight)
- I never see them on sale. (Can't imagine why :-)

-dkl

Douglas Landau said:

Quoted message said:

I own tires with 120 count and with 66 thread count. I really can't
tell the difference. Also, I usually get about the same amount of
flats with both. When I buy a tire, I try to go for weight and
price. I hate to pay anything more than 12.00 bucks, so I look for
sales.

Quoted message said:

I'm with you. Seems like there's a well-regarded tire on sale for a
great price often enough at either Nashbar or performance that if I
buy four of them, I'm good until the next good deal comes along.

Oh but there is another side to this. A low TPI tire run at high
pressure will sustain broken cords when rolling over angular obstacles
(1/2" piece of rock) and show only a distortion in the tread. The
casing being bias ply and only the inner layer fails in such bending,
a zig-zag in the tread pattern (if there is one) is the only subtle
indicator. In ant case, the blowout may come later. This was also
true in tubular days when some riders bought "kite string"
Clement-50's instead of 120TPI silks. The 50 was called a good
training tire... which it wasn't. What a slug, too.

Quoted message said:

Right now I'm riding Panaracer Stradius Elites, which I think feel
stickier but also heavier and not quite as free-rolling than the
last sale tire I tried which was Michelin Hi-Lite Prestige. Gonna
order some of the $13 Conti 3000s on sale at performance right now.

I guess that depends on what you do with them. Just cruising on
smooth pavement shouldn't cause any problems.

Jobst Brandt
[email hidden]

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

Quoted message said:

Douglas Landau said:

Quoted message said:

I own tires with 120 count and with 66 thread count. I really can't
tell the difference. Also, I usually get about the same amount of
flats with both. When I buy a tire, I try to go for weight and
price. I hate to pay anything more than 12.00 bucks, so I look for
sales.

Quoted message said:

I'm with you. Seems like there's a well-regarded tire on sale for a
great price often enough at either Nashbar or performance that if I
buy four of them, I'm good until the next good deal comes along.

Oh but there is another side to this. A low TPI tire run at high
pressure will sustain broken cords when rolling over angular obstacles
(1/2" piece of rock) and show only a distortion in the tread. The
casing being bias ply and only the inner layer fails in such bending,
a zig-zag in the tread pattern (if there is one) is the only subtle
indicator. In ant case, the blowout may come later. This was also
true in tubular days when some riders bought "kite string"
Clement-50's instead of 120TPI silks. The 50 was called a good
training tire... which it wasn't. What a slug, too.

Interesting.

I was unclear in the way I quoted Andreas. I did not intend to comment
on thread count. I was agreeing with how much he likes to spend and
his strategy of looking for sales.

Quoted message said:

Quoted message said:

Right now I'm riding Panaracer Stradius Elites, which I think feel
stickier but also heavier and not quite as free-rolling than the
last sale tire I tried which was Michelin Hi-Lite Prestige. Gonna
order some of the $13 Conti 3000s on sale at performance right now.

I guess that depends on what you do with them. Just cruising on
smooth pavement shouldn't cause any problems.

The Stradius elites are 126 TPI. My only experience with TPI is having
bought some 33 TPI Michelins. I hated them. They were hard as a rock
and slugs. I would not buy a tire with anything less than 120 after that.

dkl

I have been using some remarkable tires called a Specialized
Armadillo. They are virtually impossible to flat because they are so
thick, but going downhill they roll much slower than regular old
tires. I tried swapping wheels on a training ride with a friend and
whoever had the Armadillos would end up loosing a bike length every 50
or so meters.

I use these tires because they are so tough, but always assumed the
very rigid casing is what caused them to roll so slowly--am I correct
in this assumption?

John Roden said:

I have been using some remarkable tires called a Specialized Armadillo.
They are virtually impossible to flat because they are so thick, but
going downhill they roll much slower than regular old tires. I tried
swapping wheels on a training ride with a friend and whoever had the
Armadillos would end up loosing a bike length every 50 or so meters.
I use these tires because they are so tough, but always assumed the very
rigid casing is what caused them to roll so slowly--am I correct in this
assumption?

Dear John,

Actually, an incredibly rigid and resilient casing (like steel) would
reduce rolling resistance. Little beyond magnetic levitation beats
steel railroad car wheels on steel rails for low rolling resistance.
(This is why no one worries about the rolling resistance of the
bicycle's hub bearings--the metal rolling resistance is infinitesimal
compared to the clumsy tires.)

Given plenty of air pressure (a marvelous spring), the same material
(rubber isn't as good as latex), and the same smooth tread (any pattern
increases rolling resistance by allowing extra squirm), what matters is
how thick the tread is and how high the loss is in the casing--the
thinner, the better.

Basically, the less material that you flex into an endless bulge as the
tire meets the road, the less energy you waste distorting it. This is
the real advantage of light tires and light tubes, the latter becoming
part of the tire under normal pressures.

Some materials absorb more energy as they flex (rubber versus latex, for
example), but the big problem with your tires is likely just that
there's so much of them. Big soggy chunks of rubber, kevlar, and cotton
with block treads squirming uselessly to the sides don't roll as well as
thin, smooth wafers of highly pressurized latex and silk.

With luck, more learned types will expound on the details and correct
any misconceptions.

Carl Fogel

--

RE/

Quoted message said:

Basically, the less material that you flex into an endless bulge as the
tire meets the road, the less energy you waste distorting it. This is
the real advantage of light tires and light tubes, the latter becoming
part of the tire under normal pressures.

As long as the road is smooth....
--
PeteCresswell

carlfogel said:

Basically, the less material that you flex into an endless bulge as the
tire meets the road, the less energy you waste distorting it. This is
the real advantage of light tires and light tubes, the latter becoming
part of the tire under normal pressures.
Some materials absorb more energy as they flex (rubber versus latex, for
example), but the big problem with your tires is likely just that
there's so much of them. Big soggy chunks of rubber, kevlar, and cotton
with block treads squirming uselessly to the sides don't roll as well as
thin, smooth wafers of highly pressurized latex and silk.
Carl Fogel

I like this line of reasoning. However, if you are saying that stiffer
tires = less rolling resistance due to less footprint where the tire
rubber meets the road, then why would lighter thinner casing tires such
as those with higher TPI count = less rolling resistance? Wouldn't you
get more rolling resistance due to the thinner tire deforming more under
the rider's weight and hence a bigger footprint where the tire rubber
meets the road?

--

Quoted message said:

Oh, I've forgot, I used from latex to
heavy duty tubes, tubes with slime, and tubes surrounded by a second
tube. I can't tell the difference either. Right now, I stick to the
chepest butyl tube that I can find. I usually use tires until there is
nothing left. If a tire gets a big tear, I cut a plastic cup and use
the plastic to boot it. I get rid of tires when I have two or three
boots.

On that note, my commuter bikes have next to always been old 27"
ten-speeds. I use those thick, thorn-resistant tubes because, when
they do flat, they allow me to keep riding to my destination before I
do something about it. Run-flat, if you will.

some alcoholic said:

I like this line of reasoning. However, if you are saying that stiffer
tires = less rolling resistance due to less footprint where the tire
rubber meets the road, then why would lighter thinner casing tires such
as those with higher TPI count = less rolling resistance? Wouldn't you
get more rolling resistance due to the thinner tire deforming more under
the rider's weight and hence a bigger footprint where the tire rubber
meets the road?

You miss two of Carl’s points. The first has to do with the nature of
the materials. In the railway wheel analogy the steel is behaving
elastically at the contact patch – it is being loaded and unloaded along
the same (linear) path in the load versus elongation plot. As work is
force times the distance the force moves, no net work is being done.

In the case of the bicycle tyre, you are dealing with an anelastic
material. Because its force vs elongation characteristic exhibits
hysteresis, work must be done on it during loading and unloading. The
rate of doing work is power and this power comes from the rider’s legs.

The area of the contact patch of a tyre is almost solely a function of
force on the tyre (the weight) and its pressure. This just comes from
the definition of pressure (force/area). The force supported by the
sidewalls is negligible for a feasible bicycle tyre. Try pressing a
fully deflated tyre with your thumb. So the thick walled tyre will have
essentially the same contact patch area as its thin walled counterpart
and will absorb more of the rider’s power in hysteresis loss as its
walls deform as it rolls along. Just like Carl said.

John Retchford

--

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

Quoted message said:

.... However, if you are saying that stiffer
tires = less rolling resistance due to less footprint where the tire
rubber meets the road, then why would lighter thinner casing tires such
as those with higher TPI count = less rolling resistance? Wouldn't you
get more rolling resistance due to the thinner tire deforming more under
the rider's weight and hence a bigger footprint where the tire rubber
meets the road?

How much footprint there is depends upon the PSI to which the tire is
inflated, not how stiff it is. If the tires are inflated to 20PSI,
and the bike+rider weigh 200 lbs, then the tires are going to lay
down ten square inches of rubber, no matter what.

dl

Quoted message said:

The area of the contact patch of a tyre is almost solely a function of
force on the tyre (the weight) and its pressure. This just comes from
the definition of pressure (force/area). The force supported by the
sidewalls is negligible for a feasible bicycle tyre. Try pressing a
fully deflated tyre with your thumb. So the thick walled tyre will have
essentially the same contact patch area as its thin walled counterpart
and will absorb more of the rider's power in hysteresis loss as its
walls deform as it rolls along. Just like Carl said.

Wow, this is cool - I know what you're talking about, hysteresis and such.
(I'm a college student studying mechanical engineering) What I don't get is
whether the thick-sidewall tire has more or less rolling resistance compared
to the thin-walled tire.

--
Phil, Squid-in-Training

Douglas Landau said:

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

Quoted message said:

.... However, if you are saying that stiffer tires = less rolling
resistance due to less footprint where the tire rubber meets the
road, then why would lighter thinner casing tires such as those with
higher TPI count = less rolling resistance? Wouldn't you get more
rolling resistance due to the thinner tire deforming more under the
rider's weight and hence a bigger footprint where the tire rubber
meets the road?

How much footprint there is depends upon the PSI to which the tire is
inflated, not how stiff it is. If the tires are inflated to 20PSI, and
the bike+rider weigh 200 lbs, then the tires are going to lay down ten
square inches of rubber, no matter what.
dl

Yes, but a thinner tire leads to greater deformation under load and thus
a larger contact area with the road. Greater contact area with road =
greater rolling resistance.

--

Zeeexsixare said:

Quoted message said:

The area of the contact patch of a tyre is almost solely a function of
force on the tyre (the weight) and its pressure. This just comes from
the definition of pressure (force/area). The force supported by the
sidewalls is negligible for a feasible bicycle tyre. Try pressing a
fully deflated tyre with your thumb. So the thick walled tyre will
have essentially the same contact patch area as its thin walled
counterpart and will absorb more of the rider's power in hysteresis
loss as its walls deform as it rolls along. Just like Carl said.

Wow, this is cool - I know what you're talking about, hysteresis and
such. (I'm a college student studying mechanical engineering) What I
don't get is whether the thick- sidewall tire has more or less rolling
resistance compared to the thin-walled tire.

The thick walled tyre will have more rolling resistance than the thin
walled one, other things being equal. The rider must do more work on the
walls in the region of the rolling contact patch to deform them.

John Retchford

--

John Retchford said:

Quoted message said:

I like this line of reasoning. However, if you are saying that
stiffer tires = less rolling resistance due to less footprint where
the tire rubber meets the road, then why would lighter thinner
casing tires such as those with higher TPI count = less rolling
resistance? Wouldn't you get more rolling resistance due to the
thinner tire deforming more under the rider's weight and hence a
bigger footprint where the tire rubber meets the road?

Quoted message said:

You miss two of Carl's points. The first has to do with the nature
of the materials. In the railway wheel analogy the steel is
behaving elastically at the contact patch? it is being loaded and
unloaded along the same (linear) path in the load versus elongation
plot. As work is force times the distance the force moves, no net
work is being done.

Steel isn't entirely without losses and that is why, for instance, a
loaded rail car cannot be pushed by hand on a level track with
trivial. Part of that is cause by sag in the rail, placing the car's
wheels in depressions and the rest is hysteretic losses in steel.
There are losses in steel just as there are looses in tires.

Quoted message said:

In the case of the bicycle tyre, you are dealing with an elastic
material. Because its force vs elongation characteristic exhibits
hysteresis, work must be done on it during loading and unloading.
The rate of doing work is power and this power comes from the
rider's legs.

Let's not get the rider involved in RR of bicycle tires. That only
clouds the matter. It might be worth mentioning that hysteresis is
the characteristic by which some of the force that deformed the
material is not returned as force on rebound but generates heat. High
temper steels have little hysteresis compared to mild steel while
rubber has far greater losses. Typically a toy monkey hanging on a
steel spring and a rubber band, the one on the rubber band will stop
bouncing long before the one on steel comes to rest.

Quoted message said:

The area of the contact patch of a tyre is almost solely a function
of force on the tyre (the weight) and its pressure. This just comes
from the definition of pressure (force/area). The force supported
by the sidewalls is negligible for a feasible bicycle tyre. Try
pressing a fully deflated tyre with your thumb. So the thick walled
tyre will have essentially the same contact patch area as its thin
walled counterpart and will absorb more of the rider's power in
hysteresis loss as its walls deform as it rolls along. Just like
Carl said.

Well, "AS Carl said" but the reasons for low TPI tires having greater
losses than high TPI tires has been discussed here at great length,
recently. Maybe a GOOGLE search would help. In any case, there is an
FAQ abut this at:

http://draco.acs.uci.edu/rbfaq/FAQ/8b.14.html

Jobst Brandt
[email hidden]

John Retchford said:

Quoted message said:

I like this line of reasoning. However, if you are saying that
stiffer tires = less rolling resistance due to less footprint where
the tire rubber meets the road, then why would lighter thinner
casing tires such as those with higher TPI count = less rolling
resistance? Wouldn't you get more rolling resistance due to the
thinner tire deforming more under the rider's weight and hence a
bigger footprint where the tire rubber meets the road?

Quoted message said:

You miss two of Carl's points. The first has to do with the nature
of the materials. In the railway wheel analogy the steel is
behaving elastically at the contact patch? it is being loaded and
unloaded along the same (linear) path in the load versus elongation
plot. As work is force times the distance the force moves, no net
work is being done.

Steel isn't entirely without losses and that is why, for instance, a
loaded rail car cannot be pushed by hand on a level track. Part of
that is cause by sag in the rail, placing the car's wheels in
depressions while the rest is hysteretic losses in steel. There are
losses in steel just as there are looses in tires.

Quoted message said:

In the case of the bicycle tyre, you are dealing with an elastic
material. Because its force vs elongation characteristic exhibits
hysteresis, work must be done on it during loading and unloading.
The rate of doing work is power and this power comes from the
rider's legs.

Let's not get the rider involved in RR of bicycle tires. That only
clouds the matter. It might be worth mentioning that hysteresis is
the characteristic by which some of the force that deformed the
material is not returned as force on rebound but generates heat. High
temper steels have little hysteresis compared to mild steel while
rubber has far greater losses. Typically a toy monkey hanging on a
steel spring and a rubber band, the one on the rubber band will stop
bouncing long before the one on steel comes to rest.

Quoted message said:

The area of the contact patch of a tyre is almost solely a function
of force on the tyre (the weight) and its pressure. This just comes
from the definition of pressure (force/area). The force supported
by the sidewalls is negligible for a feasible bicycle tyre. Try
pressing a fully deflated tyre with your thumb. So the thick walled
tyre will have essentially the same contact patch area as its thin
walled counterpart and will absorb more of the rider's power in
hysteresis loss as its walls deform as it rolls along. Just like
Carl said.

Well, "AS Carl said" but the reasons for low TPI tires having greater
losses than high TPI tires has been discussed here at great length,
recently. Maybe a GOOGLE search would help. In any case, there is an
FAQ abut this at:

http://draco.acs.uci.edu/rbfaq/FAQ/8b.14.html

Jobst Brandt
[email hidden]

BaCardi said:

Douglas Landau said:

How much footprint there is depends upon the PSI to which the tire is
inflated, not how stiff it is. If the tires are inflated to 20PSI, and
the bike+rider weigh 200 lbs, then the tires are going to lay down ten
square inches of rubber, no matter what.

Quoted message said:

Yes, but a thinner tire leads to greater deformation under load and thus
a larger contact area with the road. Greater contact area with road =greater
rolling resistance.

You might want to go back and read what Doug is patiently trying to
explain to you.

The area of the contact patch is determined by the pressure in the tire
and the weight carried.

--
Ted Bennett
Portland OR

Ted Bennett said:

BaCardi said:

Douglas Landau said:

How much footprint there is depends upon the PSI to which the tire
is inflated, not how stiff it is. If the tires are inflated to
20PSI, and the bike+rider weigh 200 lbs, then the tires are going
to lay down ten square inches of rubber, no matter what.

Yes, but a thinner tire leads to greater deformation under load and
thus a larger contact area with the road. Greater contact area with
road =greater rolling resistance.

You might want to go back and read what Doug is patiently trying to
explain to you.
The area of the contact patch is determined by the pressure in the tire
and the weight carried.
--
Ted Bennett Portland OR

OK, and your premise is based on the area of contact patch IS determined
by the pressure in the tire and weight. Right? So, so basically what you
and Doug are saying is not the same as what Jobst patiently explained. I
think you ought to go back and read what Jobst is saying.

--