Cycling Equipment · Public discussion

Marketing parlance ?

Jim · 2003-04-02T18:00:07+00:00

From the zipp website... We have known for years that tire pressures over 120 psi can actually increase rolling resistance as the tire treads are pushed past their elastic limit and high local input stresses can lead to higher than allowable strains which begin to actually fail the rubber in shear. High tire pressures only feels fast, as an increase in pressure will increase the frequency at which the tire vibrates, and in turn transfers more vibration into the hub and rider. This results not only in increased rolling resistance as the rubber begins to build heat, but also to increased tire degradation and wear, not to mention wear and tear on the rider Really ?

Started by Jim · 2 April 2003 · Last activity 6 April 2003 · 15 posts · 657 views

← Back to Cycling Equipment

Thread navigation

Jump through the discussion

Go to the original post, the replies on this page, or the latest preserved contribution.

01 / Original postMarketing parlance ?Jim · 2 Apr 2003 02 / This pagePosts 1–15Page 1 of 1 · chronological order 03 / Latest replyPost #15Phil Holman · 6 Apr 2003

Thread details

What we know about this thread

Original section: Cycling Equipment
Published: 2 April 2003
Last activity: 6 April 2003
Original author: Jim
Posts: 15
Discussion status: Public discussion
Total views: 657
Views / 30 days: 0
Topics: Tyre pressure Inner tubes Punctures and flats

The navigation and discussion metadata provide context. Posts remain in their original chronological order.

Original post
Jim
Archived post

2 April 2003, 18:00 UTC #1

From the zipp website...
We have known for years that tire pressures over 120 psi can actually increase rolling resistance as
the tire treads are pushed past their elastic limit and high local input stresses can lead to higher
than allowable strains which begin to actually fail the rubber in shear. High tire pressures only
feels fast, as an increase in pressure will increase the frequency at which the tire vibrates, and
in turn transfers more vibration into the hub and rider. This results not only in increased rolling
resistance as the rubber begins to build heat, but also to increased tire degradation and wear, not
to mention wear and tear on the rider
Really ?

Report
Ken
Archived post

2 April 2003, 18:30 UTC #2

"Jim" <[email hidden]> wrote in :"]news:[email hidden]:
Quoted message said:
We have known for years that tire pressures over 120 psi can actually increase rolling resistance
I don't know about that rolling resistance claim, but here are a couple of other articles that
recommend more moderate road tire pressures (like 100psi):
roadbikerider.comua4.htm 20Better
sheldonbrown.comtires.html
Their arguments make sense to me.

Report
Tc Rider
Archived post

2 April 2003, 20:00 UTC #3

Jim <[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
From the zipp website...
We have known for years that tire pressures over 120 psi can actually increase rolling resistance
as the tire treads are pushed past their

elastic
Quoted message said:
limit and high local input stresses can lead to higher than allowable strains which begin to
actually fail the rubber in shear. High tire pressures only feels fast, as an increase in
pressure will increase the frequency at which the tire vibrates, and in turn transfers more
vibration into the hub and rider. This results not only in increased rolling resistance as the
rubber begins to build heat, but also to increased tire degradation and wear, not to mention wear
and tear on the rider
Really ?
Marketing?! What would Zipp have to gain by telling people how to make tires last longer? I'd say
it's probably on the level, though I have to wonder at the magnitude of some of the effects...

Report
Bfd
Archived post

2 April 2003, 23:00 UTC #4

Ken <[email hidden]> wrote in message news:<[email hidden]>...
Quoted message said:
"Jim" <[email hidden]> wrote in :"]news:[email hidden]:
Quoted message said:
We have known for years that tire pressures over 120 psi can actually increase rolling
resistance
I don't know about that rolling resistance claim, but here are a couple of other articles that
recommend more moderate road tire pressures (like 100psi):
roadbikerider.comua4.htm 20Better
sheldonbrown.comtires.html
Their arguments make sense to me.

You may also want to add this to your reading... discussion
terrymorse.comrrdiscuss.html graphs terrymorse.comrolres.html

Report
Jobst Brandt
Archived post

3 April 2003, 01:30 UTC #5

Jim who? quotes:
Quoted message said:
"We have known for years that tire pressures over 120 psi can actually increase rolling resistance
as the tire treads are pushed past their elastic limit and high local input stresses can lead to
higher than allowable strains which begin to actually fail the rubber in shear. High tire
pressures only feels fast, as an increase in pressure will increase the frequency at which the
tire vibrates, and in turn transfers more vibration into the hub and rider. This results not only
in increased rolling resistance as the rubber begins to build heat, but also to increased tire
degradation and wear, not to mention wear and tear on the rider."
Quoted message said:
Really ?
No! Not the part about an increase in RR. That is pure fiction as the curves at:
terrymorse.comrolres.html
show. That is because, as often, manufacturers don't understand their products, the engineering
skills for that having sought more rewarding positions. Rolling resistance is not caused by road
scrubbing as myth and lore tells us, but rather through losses in elastic materials used in tires.
Old-timers may recall when the first durable clincher was offered by Specialized, it had a 1/4"
raised center ridge that was claimed to reduce RR by minimizing scrub (road contact). In fact the
tire had its highest RR when new and after the ridge was flush with the rest of the surface, was
lower. Elastomer losses include the inter-cord matrix that holds the casing together, and the tread.
The tube also becomes an integral part of the tire when inflated. The higher the pressure the less
the tire flexes, and therefore, the lower the RR. That's pretty simple but beyond the scope of the
folks in charge of the product who are, no doubt, in charge of the hype in the PR texts.
As to wear, they should show some wear curves to support their claim. That is to say, where is the
optimum. We don't want to ride flat tires and too high a pressure endangers the rider with tire
blow-off and greater wear.
Jobst Brandt [email hidden] Palo Alto CA

Report
W K
Archived post

4 April 2003, 14:00 UTC #6

<[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
Jim who? quotes:
Quoted message said:
"We have known for years that tire pressures over 120 psi can actually increase rolling
resistance as the tire treads are pushed past their elastic limit and high local input stresses
can lead to higher than allowable strains which begin to actually fail the rubber in shear. High
tire pressures only feels fast, as an increase in pressure will increase the frequency at which
the tire vibrates, and in turn transfers more vibration into the hub and rider. This results not
only in increased rolling resistance as the rubber begins to build heat, but also to increased
tire degradation and wear, not to mention wear and tear on the rider."
Quoted message said:
Really ?
No! Not the part about an increase in RR. That is pure fiction as the curves at:
terrymorse.comrolres.html
show.
Those tests were done on a smooth drum of course. How important are the energy losses associated
with going over a rough surface with less suspension (from higher pressure in the tires)?
Its not a personal pet theory of mine or anything, but I have seen theories based on something like
the above, in that when dealing with a slightly rough road surface the ability of a tire to act as
suspension may be more of an advantage than that given by the lower "smooth surface RR".

Report
Jobst Brandt
Archived post

4 April 2003, 20:00 UTC #7

W K snipes anonymously:
Quoted message said:
Quoted message said:
Quoted message said:
"We have known for years that tire pressures over 120 psi can actually increase rolling
resistance as the tire treads are pushed past their elastic limit and high local input stresses
can lead to higher than allowable strains which begin to actually fail the rubber in shear. High
tire pressures only feels fast, as an increase in pressure will increase the frequency at which
the tire vibrates, and in turn transfers more vibration into the hub and rider. This results not
only in increased rolling resistance as the rubber begins to build heat, but also to increased
tire degradation and wear, not to mention wear and tear on the rider."
Quoted message said:
Quoted message said:
Quoted message said:
Really ?
Quoted message said:
Quoted message said:
No! Not the part about an increase in RR. That is pure fiction as the curves at:
Quoted message said:
Quoted message said:
terrymorse.comrolres.html
Quoted message said:
Quoted message said:
show.
Quoted message said:
Those tests were done on a smooth drum of course. How important are the energy losses associated
with going over a rough surface with less suspension (from higher pressure in the tires)?
Maybe you can describe a model of what you believe happens on a paved road of typical asphalt
roughness that would change rolling resistance response of a tire. Do not omit an energy equation
that shows where these losses are converted to heat, the result of all energy losses. Note that tire
deflection from a rider sitting on the bicycle is greater than pavement roughness, that is if this
enters into the model you visualize.
Quoted message said:
Its not a personal pet theory of mine or anything, but I have seen theories based on something
like the above, in that when dealing with a slightly rough road surface the ability of a tire to
act as suspension may be more of an advantage than that given by the lower "smooth surface RR".
Before repeating these pseudo-science tales, you might look into their validity. Myth and lore
survives on repetition, not fact.
You might also consider:
draco.acs.uci.edu8b.25.html
Jobst Brandt [email hidden] Palo Alto CA

Report
Doug Milliken
Archived post

4 April 2003, 20:30 UTC #8

On Thu, 3 Apr 2003 [email hidden] wrote:
<snipped comments on rolling resistance>
Quoted message said:
As to wear, they should show some wear curves to support their claim. That is to say, where is the
optimum. We don't want to ride flat tires and too high a pressure endangers the rider with tire
blow-off and greater wear.
Jobst Brandt [email hidden] Palo Alto CA
Does anyone know of a good test procedure for bicycle tire wear tests?
I know that for truck tires (trucking fleets spend a lot of money on replacement tires) there has
been a lot of work done to characterize wear and none is really conclusive. The problem seems to be
that wear is very nonlinear with small changes in operating conditions. For example, different
drivers on the same delivery route may get 2:1 or even more difference in tread life.
-- Doug Milliken www.millikenresearch.com

Report
Phil Holman
Archived post

5 April 2003, 05:00 UTC #9

<[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
W K snipes anonymously:
Quoted message said:
Quoted message said:
> "We have known for years that tire pressures over 120 psi can
> actually increase rolling resistance as the tire treads are

pushed
Quoted message said:
Quoted message said:
Quoted message said:
> past their elastic limit and high local input stresses can lead

to
Quoted message said:
Quoted message said:
Quoted message said:
> higher than allowable strains which begin to actually fail the rubber in shear. High tire
> pressures only feels fast, as an increase in pressure will increase the frequency at which
> the

tire
Quoted message said:
Quoted message said:
Quoted message said:
> vibrates, and in turn transfers more vibration into the hub and rider. This results not only
> in increased rolling resistance as the rubber begins to build heat, but also to increased
> tire degradation and wear, not to mention wear and tear on the rider."
Quoted message said:
Quoted message said:
> Really ?
Quoted message said:
Quoted message said:
No! Not the part about an increase in RR. That is pure fiction as the curves at:
Quoted message said:
Quoted message said:
terrymorse.comrolres.html
Quoted message said:
Quoted message said:
show.
Quoted message said:
Those tests were done on a smooth drum of course. How important are the energy losses associated
with going over a rough surface with less suspension (from higher pressure in the tires)?
Maybe you can describe a model of what you believe happens on a paved road of typical asphalt
roughness that would change rolling resistance response of a tire. Do not omit an energy equation
that shows where these losses are converted to heat, the result of all energy losses. Note that
tire deflection from a rider sitting on the bicycle is greater than pavement roughness, that is if
this enters into the model you visualize.
Quoted message said:
Its not a personal pet theory of mine or anything, but I have seen theories based on something
like the above, in that when dealing with a slightly rough road surface the ability of a tire to
act as suspension may be more of an advantage than that given by the lower "smooth surface RR".
Before repeating these pseudo-science tales, you might look into their validity. Myth and lore
survives on repetition, not fact.
What is the essence of the contention here? Do riders use more energy rolling over chip seal at 140
psi than at 100psi? I know which is more comfortable and there is no doubt that riding over chip
seal is slower than on smooth pavement.
Phil Holman

Report
Jobst Brandt
Archived post

5 April 2003, 05:00 UTC #10

Phil Holman said:
What is the essence of the contention here? Do riders use more energy rolling over chip seal at
140 psi than at 100psi?
That is the contention as I understand it and it has been proposed many times before. Repetition
does not make it so. There is no evidence that comfort has any parallel in rolling losses in
tires unless it is inverse. Just the nature of tire rolling resistance, which arises from viscous
losses in tire elastomers, points to lower losses with increasing pressure within the limits of
actual tires.
Jobst Brandt [email hidden] Palo Alto CA

Report
W K
Archived post

5 April 2003, 11:30 UTC #11

<[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
W K snipes anonymously:
My name is William Kemp BTW.
Quoted message said:
Quoted message said:
Those tests were done on a smooth drum of course. How important are the energy losses associated
with going over a rough surface with less suspension (from higher pressure in the tires)?
Maybe you can describe a model of what you believe happens on a paved road of typical asphalt
roughness that would change rolling resistance response of a tire. Do not omit an energy equation
that shows where these losses are converted to heat, the result of all energy losses. Note that
tire deflection from a rider sitting on the bicycle is greater than pavement roughness, that is if
this enters into the model you visualize.
Ah, I see, If I cannot give you a realistic scenario based on science I am not allowed to even ask
whether there is an effect caused by rough roads.
Science needs simple questions before you arrive at a complex answer. Are there figures for how
rolling resistance varies with tyre pressure on a rough surface?
Quoted message said:
Quoted message said:
Its not a personal pet theory of mine or anything, but I have seen theories based on something
like the above, in that when dealing with a slightly rough road surface the ability of a tire to
act as suspension may be more of an advantage than that given by the lower "smooth surface RR".
Before repeating these pseudo-science tales, you might look into their validity. Myth and lore
survives on repetition, not fact.
Simple questions:
Do people riding on rougher roads experience more rolling resistance?
Sorry, I cannot explain if this is true in terms of energy loss.

Report
Jobst Brandt
Archived post

5 April 2003, 19:00 UTC #12

William Kemp said:
Quoted message said:
Quoted message said:
Those tests were done on a smooth drum of course. How important are the energy losses associated
with going over a rough surface with less suspension (from higher pressure in the tires)?
Quoted message said:
Quoted message said:
Maybe you can describe a model of what you believe happens on a paved road of typical asphalt
roughness that would change rolling resistance response of a tire. Do not omit an energy equation
that shows where these losses are converted to heat, the result of all energy losses. Note that
tire deflection from a rider sitting on the bicycle is greater than pavement roughness, that is
if this enters into the model you visualize.
Quoted message said:
Ah, I see, If I cannot give you a realistic scenario based on science I am not allowed to even ask
whether there is an effect caused by rough roads.
Certainly there is an effect of rough roads but it is not one that will change the nature of
reducing rolling resistance as pressure is increased. The amount of tire distortion increases with
roughness as does rolling resistance. You can test that if you have a suitable road by riding on or
off the chip seal and noting the speed. I had the opportunity of doing that on the north slope of
Monitor Pass on US 395. There was a repeatably lower speed on the rougher surface.
Quoted message said:
Science needs simple questions before you arrive at a complex answer. Are there figures for how
rolling resistance varies with tyre pressure on a rough surface?
Not that I know of. Of course, from knowing that tread squirm, typical of patterned treads where
tread rubber bulges into tread voids, impressing angular pavement features into a smooth tread will
also cause tread squirm. Tread squirm is the principal loss in knobby tires rolling on smooth
pavement. This has been measured.
Quoted message said:
Quoted message said:
Quoted message said:
Its not a personal pet theory of mine or anything, but I have seen theories based on something
like the above, in that when dealing with a slightly rough road surface the ability of a tire to
act as suspension may be more of an advantage than that given by the lower "smooth surface RR".
Quoted message said:
Quoted message said:
Before repeating these pseudo-science tales, you might look into their validity. Myth and lore
survives on repetition, not fact.
Quoted message said:
Simple questions:
Quoted message said:
Do people riding on rougher roads experience more rolling resistance?
Yes.
Quoted message said:
Sorry, I cannot explain if this is true in terms of energy loss.
Tire losses are almost entirely due to tread, casing, and inner tube flexing while the least losses
are caused by tread scrubbing on the road. If this were not the case tires would wear out much
faster than they do.
Jobst Brandt [email hidden] Palo Alto CA

Report
Phil Holman
Archived post

5 April 2003, 21:30 UTC #13

<[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
William Kemp said:
Quoted message said:
> Those tests were done on a smooth drum of course. How important are the energy losses
> associated with going over a rough surface with less suspension (from higher pressure in the
> tires)?
Quoted message said:
Quoted message said:
Maybe you can describe a model of what you believe happens on a paved road of typical asphalt
roughness that would change rolling resistance response of a tire. Do not omit an energy
equation that shows where these losses are converted to heat, the result of all energy losses.
Note that tire deflection from a rider sitting on the bicycle is greater than pavement
roughness, that is if this enters into the model you visualize.
Quoted message said:
Ah, I see, If I cannot give you a realistic scenario based on science I am not allowed to even
ask whether there is an effect caused by rough roads.
Certainly there is an effect of rough roads but it is not one that will change the nature of
reducing rolling resistance as pressure is increased. The amount of tire distortion increases with
roughness as does rolling resistance. You can test that if you have a suitable road by riding on
or off the chip seal and noting the speed. I had the opportunity of doing that on the north slope
of Monitor Pass on US 395. There was a repeatably lower speed on the rougher surface.
Quoted message said:
Science needs simple questions before you arrive at a complex answer. Are there figures for how
rolling resistance varies with tyre pressure on a rough surface?
Not that I know of. Of course, from knowing that tread squirm,

typical
Quoted message said:
of patterned treads where tread rubber bulges into tread voids, impressing angular pavement
features into a smooth tread will also cause tread squirm. Tread squirm is the principal loss in
knobby tires rolling on smooth pavement. This has been measured.
Quoted message said:
Quoted message said:
> Its not a personal pet theory of mine or anything, but I have seen theories based on something
> like the above, in that when dealing with a slightly rough road surface the ability of a tire
> to act as suspension may be more of an advantage than that given by the lower "smooth surface
> RR".
Quoted message said:
Quoted message said:
Before repeating these pseudo-science tales, you might look into their validity. Myth and lore
survives on repetition, not fact.
Quoted message said:
Simple questions:
Quoted message said:
Do people riding on rougher roads experience more rolling

resistance?
Quoted message said:

Yes.
Quoted message said:
Sorry, I cannot explain if this is true in terms of energy loss.
Tire losses are almost entirely due to tread, casing, and inner tube flexing while the least
losses are caused by tread scrubbing on the road. If this were not the case tires would wear out
much faster than they do.
On a rough surface, if the tires are inflated so high as to cause an upward velocity component of
the bicycle and rider, then surely the losses are not just limited to the flexing of the tires.
Phil Holman

Report
Jobst Brandt
Archived post

6 April 2003, 02:00 UTC #14

Phil Holman said:
Quoted message said:
Quoted message said:
Sorry, I cannot explain if this is true in terms of energy loss.
Quoted message said:
Quoted message said:
Tire losses are almost entirely due to tread, casing, and inner tube flexing while the least
losses are caused by tread scrubbing on the road. If this were not the case tires would wear out
much faster than they do.
Quoted message said:
On a rough surface, if the tires are inflated so high as to cause an upward velocity component of
the bicycle and rider, then surely the losses are not just limited to the flexing of the tires.
There is always a vertical component when not on glassy surfaces. You can feel even smooth concrete
decks of bridges in the handlebars. In that case, you should be able to explain where you see energy
being converted to heat. Rolling resistance refers to the losses in tires, not someone's flabby body
parts vibrating. In any case, that scenario may interest someone somewhere but comfort becomes more
of an issue in that domain. We're talking rolling resistance here and what you bring up is
classically where these discussions end, somewhere in someone's fat ass.
Think tires!
Jobst Brandt [email hidden] Palo Alto CA

Report
Phil Holman
Archived post

6 April 2003, 03:30 UTC #15

<[email hidden]> wrote in message "]news:[email hidden]...
Quoted message said:
Phil Holman said:
Quoted message said:
> Sorry, I cannot explain if this is true in terms of energy loss.
Quoted message said:
Quoted message said:
Tire losses are almost entirely due to tread, casing, and inner tube flexing while the least
losses are caused by tread scrubbing on the road. If this were not the case tires would wear
out much faster than they do.
Quoted message said:
On a rough surface, if the tires are inflated so high as to cause an upward velocity component
of the bicycle and rider, then surely the losses are not just limited to the flexing of the
tires.
There is always a vertical component when not on glassy surfaces. You can feel even smooth
concrete decks of bridges in the handlebars. In that case, you should be able to explain where you
see energy being converted to heat. Rolling resistance refers to the losses in tires, not
someone's flabby body parts vibrating. In any case, that scenario may interest someone somewhere
but comfort becomes more of an issue in that domain. We're talking rolling resistance here and
what you bring up is classically where these discussions end, somewhere in someone's fat ass.
Think tires!
You are absolutely correct in your definition of rolling resistance. Unlike the original post, I do
not include the effects of too high a tire pressure and rough roads in that definition. Phil Holman

Report

Active in the last 60 minutes

Active in this thread

0 users · 0 guests ·0 bots ·0 total

No signed-in users are active right now.

No known search crawlers active right now.

Jump through the discussion

What we know about this thread

Continue through CyclingForums

Active in this thread