Re: Rim brake heat and clincher blowoff, was Re: Potential good news for Mt. Washington access.

[[email protected]]

Andrew Muzi writes:

>> These insulating rim tapes were available at the time when we were
>> all riding tubulars and when we switched to clinchers, no one
>> recalled these insulators, or for that matter, recognized that they
>> were insulators. These rim strips are loose bias weave cotton
>> 'hoses' about 10mm in diameter, filled with kapok having a short
>> flat piece of rubberized cloth with at the stem hole. They do not
>> interfere with the tire mounting because they can be compressed
>> laterally and then conform to the bed of the rim between the beads
>> of the tire on inflation.

>> I recall that they, as the Clement hard glue for tubulars, were a
>> mystery to riders of that era.

> We called them 'rim ropes' and only experienced tandem tourists
> bought them. Only 2 sources I ever knew- Mike Sinyard before he was
> rich and Sal Corso.

> You're right most riders had no idea. An older tourist explained it
> to me as I was about to throw his away. . .

Long live the rim rope. I hope to see it return.

Jobst Brandt
[email protected]

 

[Mike DeMicco]

In article <[email protected]>,
[email protected] wrote:


> > Plastic rim tape melts and that forces the tube into the nipple socket
> > or puts the tube more directly in contact with the hot rim.
>
> Oh BS! I've been riding Kool-Stop plastic rim strips for many years
> and have not had any problems, hot as my rims have gotten. I now have
> one Rolf plastic/mesh rim strip that also works fine. Pleas explain
> on what you base this finding.

I had this happen to me with red plastic rim strips made by Specialized
some years ago (extruded into a spoke hole). Perhaps the Kool-Stops are
made of plastic with a higher melting point.

--
Mike DeMicco <[email protected]>
(Remove the REMOVE_THIS from my email address to reply.)

 

[Alfred Ryder]

Jobst Brandt wrote
>
> >> These insulating rim tapes were available at the time when we were
> >> all riding tubulars and when we switched to clinchers, no one
> >> recalled these insulators, or for that matter, recognized that they
> >> were insulators. These rim strips are loose bias weave cotton
> >> 'hoses' about 10mm in diameter, filled with kapok having a short
> >> flat piece of rubberized cloth with at the stem hole. They do not
> >> interfere with the tire mounting because they can be compressed
> >> laterally and then conform to the bed of the rim between the beads
> >> of the tire on inflation.
>
> >> I recall that they, as the Clement hard glue for tubulars, were a
> >> mystery to riders of that era.
>
> > We called them 'rim ropes' and only experienced tandem tourists
> > bought them. Only 2 sources I ever knew- Mike Sinyard before he was
> > rich and Sal Corso.
>
> > You're right most riders had no idea. An older tourist explained it
> > to me as I was about to throw his away. . .
>
> Long live the rim rope. I hope to see it return.

Did "experienced tandem tourists" use thermally insulating rim rope to
reduce the occurrence of tire blow-off from hot rims? That is implied in the
above.

Also the first sentence above implies that insulating rim tapes were used
with tubular tires. But I don't understand why. Do tubulars blow off from
hot rims. I thought it was only a problem with clinchers. And I would not
expect insulating rim tape to reduce glue softening from rim heating. What
was the purpose of insulating rim tape with tubulars?

 

[A Muzi]

>>> [email protected] wrote:
>>> These insulating rim tapes were available at the time when we were all
>>> riding tubulars and when we switched to clinchers, no one recalled
>>> these insulators, or for that matter, recognized that they were
>>> insulators. These rim strips are loose bias weave cotton 'hoses'
>>> about 10mm in diameter, filled with kapok having a short flat piece of
>>> rubberized cloth with at the stem hole.

(am) >> We called them 'rim ropes' and only experienced
tandem tourists bought
>> them. Only 2 sources I ever knew- Mike Sinyard before he was rich and
>> Sal Corso.
>> You're right most riders had no idea. An older tourist explained it to
>> me as I was about to throw his away. . .
> Same here, I remember thinking they were intolerably crude rim strips.

Mark Janeba wrote:
> Same here, I remember thinking they were intolerably
crude rim strips.
> I seem to remember a version with a flat metal "link" at the valve hole
> - can anybody corroborate that, or is my memory faulty?
> So I gather part of the point of this discussion is that they are no
> longer available? Anybody seen one lately?

Older British rim tapes were a flat cotton band and a
metal buckle. Those hold water in steel rims and should be
removed.

Rim ropes are a cotton knit tube with kapok and felt inside.
There's a sewn cotton patch at the valve hole.

My Indian bikes still ship with cotton bands and metal
buckles. We install rubber rim liners.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Tom Sherman]

Jobst Brandt wrote:

> [ This is a repost of the following article: ]
> [ From: [email protected] ]
> [ Subject: Re: Rim brake heat and clincher blowoff, was Re: Potential good news for Mt. Washington access. ]
> [ Newsgroups: rec.bicycles.misc ]
> [ Message-ID: <[email protected]> ]
>
> Matt O'Toole writes:
>
>
>>>This isn't about MTB's. It is primarily a road bicycle problem.
>>>It takes the same pressure to blow a skinny tire off a rim as a fat
>>>one, the interface being the inside width of the rim, on which
>>>inflation pressure acts (between tire and rim). If your 2.5" MTB
>>>tire on a narrow rim can withstand 140psi then you may be able to
>>>experience blow-off. On the other hand, starting at 45psi, I doubt
>>>that you could get enough pressure even if you have a wider rim.
>
>
>>So perhaps a 25mm or 28mm tire at 90psi is safer than a 23mm one at
>>120psi? Care to make an educated guess at what the threshold of
>>safety is? Wouldn't it be interesting to test this?
>
>
> Interesting that you mention that, because I am working on a test for
> blow-off. I made a valve stem pressure sensor adapter that, when
> installed, opens the Presta valve to an aneroid pressure sensor that
> sends its readings to a data-logger (about the size of a deck of
> cards) that also reads a thermocouple attached to the rim. The data
> logger is tied to the inside of the wheel near the hub and has a USB
> connector to download test data to a PC where it can be charted.
>
> The plan is to descend Hicks Road near Los Gatos CA using only the
> rear brake at about 15mph until the tire blows off. Since this is
> essentially a straight run, there is no problem stopping with a flat
> rear tire. Each such run will require a new tube and I think the
> second run should make clear whether this is reasonably repeatable.
> Of course I'll have to cool the rim down with water before running
> again and pump the tire to the same pressure.
>
> I will also test a 1950's French touring rim tape that was designed to
> prevent tire blow-off but was never recognized as such, and was
> therefore, unmarketable from the Cupertino Bike Shop of those days.
> After having not ridden down Hicks Rd. since the days of my insulated
> tubulars, I was concerned about this descent the last few times I
> recently came down that hill and recall reading about a fatality in
> 2004 on that road... attributed to lack of rider skill.
>
> Not to worry, the results will be announced. There is still a matter
> of designing a small circuit board for the thermocouple. I hope to
> see a product emerge from this.

I will brave the wrath of Jobst Brandt by suggesting that this
experiment could be made more complicated.

Coast down tests could be used to back-calculate the coefficient of
rolling resistance and CdA. If the roadway was accurately profiled and a
channel of the data logger set to take input from a properly calibrated
cyclometer, the combined information could be used to calculate how much
energy was lost to rolling resistance and aerodynamic drag. Subtracting
this loss from the potential gravitational energy converted into kinetic
energy would obtain the amount of potential energy converted into heat
during braking.

--
Tom Sherman - Near Rock Island

 

[A Muzi]

> Jobst Brandt wrote
>>>>These insulating rim tapes were available at the time when we were
>>>>all riding tubulars and when we switched to clinchers, no one
>>>>recalled these insulators, or for that matter, recognized that they
>>>>were insulators. These rim strips are loose bias weave cotton
>>>>'hoses' about 10mm in diameter, filled with kapok having a short
>>>>flat piece of rubberized cloth with at the stem hole. They do not
>>>>interfere with the tire mounting because they can be compressed
>>>>laterally and then conform to the bed of the rim between the beads
>>>>of the tire on inflation.

Alfred Ryder wrote:
> Did "experienced tandem tourists" use thermally insulating rim rope to
> reduce the occurrence of tire blow-off from hot rims? That is implied in the
> above.
>
> Also the first sentence above implies that insulating rim tapes were used
> with tubular tires. But I don't understand why. Do tubulars blow off from
> hot rims. I thought it was only a problem with clinchers. And I would not
> expect insulating rim tape to reduce glue softening from rim heating. What
> was the purpose of insulating rim tape with tubulars?

Yes and Gitane, Peugeot shipped tandems with rim ropes
installed. Motobecane did not.

The "Jantex" rim tape* adds a cotton layer between rim and
tubular. Altghough it's supposed to be glued on top and
bottom occasionally you'll meet a rider who uses that alone
to secure his tubs. I wouldn't. But then again I never knew
of one coming off either.

*dark reddish brown, slightly tacky 17mm wide. Comes foil
wrapped in a small cardboard box, smells of charcoal)

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Mark Janeba]

A Muzi wrote:
> Mark Janeba wrote:
>> I seem to remember a version with a flat metal "link" at the valve
>> hole - can anybody corroborate that, or is my memory faulty?
>> So I gather part of the point of this discussion is that they are no
>> longer available? Anybody seen one lately?

> Older British rim tapes were a flat cotton band and a metal buckle.
> Those hold water in steel rims and should be removed.

That's the one. I was working (briefly) in a Raleigh shop at the time.

Mark Janeba

 

[[email protected]]

Alfred Ryder writes:

>>>> These insulating rim tapes were available at the time when we
>>>> were all riding tubulars and when we switched to clinchers, no
>>>> one recalled these insulators, or for that matter, recognized
>>>> that they were insulators. These rim strips are loose bias weave
>>>> cotton 'hoses' about 10mm in diameter, filled with kapok having a
>>>> short flat piece of rubberized cloth with at the stem hole. They
>>>> do not interfere with the tire mounting because they can be
>>>> compressed laterally and then conform to the bed of the rim
>>>> between the beads of the tire on inflation.

>>>> I recall that they, as the Clement hard glue for tubulars, were a
>>>> mystery to riders of that era.

>>> We called them 'rim ropes' and only experienced tandem tourists
>>> bought them. Only 2 sources I ever knew- Mike Sinyard before he
>>> was rich and Sal Corso.

>>> You're right most riders had no idea. An older tourist explained
>>> it to me as I was about to throw his away. . .

>> Long live the rim rope. I hope to see it return.

> Did "experienced tandem tourists" use thermally insulating rim rope
> to reduce the occurrence of tire blow-off from hot rims? That is
> implied in the above.

Not in my area. They just sat on the shelf at the Cupertino Bike Shop
and that's why I have some now, because the things Spence Wolf had
left he bequeathed to a friend who collects such things.

> Also the first sentence above implies that insulating rim tapes were used
> with tubular tires. But I don't understand why. Do tubulars blow off from
> hot rims. I thought it was only a problem with clinchers. And I would not
> expect insulating rim tape to reduce glue softening from rim heating. What
> was the purpose of insulating rim tape with tubulars?

Not at all. We were not interested in them when we rode tubulars.
"These insulating rim tapes were available at the time when we were
all riding tubulars and when we switched to clinchers, no one recalled
these insulators, or for that matter, recognized that they were
insulators." I think that is unambiguous.

Jobst Brandt
[email protected]

 

[[email protected]]

Tom Sherman writes:

> Coast down tests could be used to back-calculate the coefficient of
> rolling resistance and CdA. If the roadway was accurately profiled
> and a channel of the data logger set to take input from a properly
> calibrated Cyclometer, the combined information could be used to
> calculate how much energy was lost to rolling resistance and
> aerodynamic drag. Subtracting this loss from the potential
> gravitational energy converted into kinetic energy would obtain the
> amount of potential energy converted into heat during braking.

I think I sense a troll detection test. We can measure the altitude
change and derive the ft lbs of energy far better. I'm not sure what
you are proposing but it doesn't seem to have anything to do with the
project. You aren't serious are you. Sometimes it's hard to tell.

Jobst Brandt
[email protected]

 

[David Damerell]

begin quoting <[email protected]>:
>Tom Sherman writes:
>>Coast down tests could be used to back-calculate the coefficient of
>>rolling resistance and CdA. If the roadway was accurately profiled
>>and a channel of the data logger set to take input from a properly
>>calibrated Cyclometer, the combined information could be used to
>>calculate how much energy was lost to rolling resistance and
>>aerodynamic drag. Subtracting this loss from the potential
>>gravitational energy converted into kinetic energy would obtain the
>>amount of potential energy converted into heat during braking.
>I think I sense a troll detection test. We can measure the altitude
>change and derive the ft lbs of energy far better.

You've missed the point of his suggestion. Yes, it is trivial to determine
the input energy; what he proposes is to try and accurately determine the
amount of that energy lost to air resistance and rolling resistance. That
and the kinetic energy at the end of the run may be subtracted from the
input energy to determine the energy that must necessarily have become
hear under braking.
--
David Damerell <[email protected]> Distortion Field!
Today is Second Teleute, January.

 

[Tom Sherman]

David Damerell wrote:

> begin quoting <[email protected]>:
>
>>Tom Sherman writes:
>>
>>>Coast down tests could be used to back-calculate the coefficient of
>>>rolling resistance and CdA. If the roadway was accurately profiled
>>>and a channel of the data logger set to take input from a properly
>>>calibrated Cyclometer, the combined information could be used to
>>>calculate how much energy was lost to rolling resistance and
>>>aerodynamic drag. Subtracting this loss from the potential
>>>gravitational energy converted into kinetic energy would obtain the
>>>amount of potential energy converted into heat during braking.
>>
>>I think I sense a troll detection test. We can measure the altitude
>>change and derive the ft lbs of energy far better.
>
>
> You've missed the point of his suggestion. Yes, it is trivial to determine
> the input energy; what he proposes is to try and accurately determine the
> amount of that energy lost to air resistance and rolling resistance. That
> and the kinetic energy at the end of the run may be subtracted from the
> input energy to determine the energy that must necessarily have become
> hear under braking.

If my proposed experiment were successfully conducted, it would be
possible to determine the amount of energy that would need to be
dissipated by braking on a given descent. From Jobst Brandt's proposed
experimental data we could then determine the factor of safety against
tire blow-off for the descent in question. This could further be
combined with real-time GPS data and stored topographic data to let the
rider know the maximum safe tire pressure before each descent.

--
Tom Sherman - Near Rock Island

 

[[email protected]]

Tom Sherman writes:

>>>> Coast down tests could be used to back-calculate the coefficient
>>>> of rolling resistance and CdA. If the roadway was accurately
>>>> profiled and a channel of the data logger set to take input from
>>>> a properly calibrated Cyclometer, the combined information could
>>>> be used to calculate how much energy was lost to rolling
>>>> resistance and aerodynamic drag. Subtracting this loss from the
>>>> potential gravitational energy converted into kinetic energy
>>>> would obtain the amount of potential energy converted into heat
>>>> during braking.

>>> I think I sense a troll detection test. We can measure the
>>> altitude change and derive the ft lbs of energy far better.

>> You've missed the point of his suggestion. Yes, it is trivial to
>> determine the input energy; what he proposes is to try and
>> accurately determine the amount of that energy lost to air
>> resistance and rolling resistance. That and the kinetic energy at
>> the end of the run may be subtracted from the input energy to
>> determine the energy that must necessarily have become hear under
>> braking.

> If my proposed experiment were successfully conducted, it would be
> possible to determine the amount of energy that would need to be
> dissipated by braking on a given descent. From Jobst Brandt's
> proposed experimental data we could then determine the factor of
> safety against tire blow-off for the descent in question. This could
> further be combined with real-time GPS data and stored topographic
> data to let the rider know the maximum safe tire pressure before
> each descent.

For which rider, clothing, ambient temperature, tire type, inflation
pressure... Let's be practical. There is a concept to be
investigated here rather than a recipe for descending. If you
consider the variables involved, your proposal becomes undefinable.

Jobst Brandt
[email protected]

 

[Tom Sherman]

Jobst Brandt wrote:

> Tom Sherman writes:
>
>
>>>>>Coast down tests could be used to back-calculate the coefficient
>>>>>of rolling resistance and CdA. If the roadway was accurately
>>>>>profiled and a channel of the data logger set to take input from
>>>>>a properly calibrated Cyclometer, the combined information could
>>>>>be used to calculate how much energy was lost to rolling
>>>>>resistance and aerodynamic drag. Subtracting this loss from the
>>>>>potential gravitational energy converted into kinetic energy
>>>>>would obtain the amount of potential energy converted into heat
>>>>>during braking.
>
>
>>>>I think I sense a troll detection test. We can measure the
>>>>altitude change and derive the ft lbs of energy far better.
>
>
>>>You've missed the point of his suggestion. Yes, it is trivial to
>>>determine the input energy; what he proposes is to try and
>>>accurately determine the amount of that energy lost to air
>>>resistance and rolling resistance. That and the kinetic energy at
>>>the end of the run may be subtracted from the input energy to
>>>determine the energy that must necessarily have become hear under
>>>braking.
>
>
>>If my proposed experiment were successfully conducted, it would be
>>possible to determine the amount of energy that would need to be
>>dissipated by braking on a given descent. From Jobst Brandt's
>>proposed experimental data we could then determine the factor of
>>safety against tire blow-off for the descent in question. This could
>>further be combined with real-time GPS data and stored topographic
>>data to let the rider know the maximum safe tire pressure before
>>each descent.
>
>
> For which rider, clothing, ambient temperature, tire type, inflation
> pressure... Let's be practical. There is a concept to be
> investigated here rather than a recipe for descending. If you
> consider the variables involved, your proposal becomes undefinable.

Jobst Brandt is correct IF we use a small factor of safety. However, if
we assume a typical case of a rider on a standard diamond frame road
bike, using normal tires, wearing cycling short and jersey, and riding
"on the drops" we can reasonably estimate the losses from rolling
resistance and aerodynamic drag. We can then choose a factor of safety
that will depend on how risk adverse the rider is.

We could dispense with the GPS. The rider would simply use his/her
judgement to pick out particular descents in advance of the ride, and
then calculate the factor of safety against tire blow-off. If the factor
of safety were too low, the rider would simply plan to reduce tire
pressure in advance or to stop and cool the rims part way down.

An entirely different approach would be to build wireless temperature
and pressure transducers into the rim. When a certain threshold was
exceeded, an alarm would be triggered. The rider would then stop and
cool the rims. Liquid cooling when riding would be an option for anyone
with a full or partially full water bottle and decent aim.

--
Tom Sherman - Near Rock Island

 

[Tom Sherman]

Jobst Brandt wrote:

> Tom Sherman writes:
>
>
>>>>>Coast down tests could be used to back-calculate the coefficient
>>>>>of rolling resistance and CdA. If the roadway was accurately
>>>>>profiled and a channel of the data logger set to take input from
>>>>>a properly calibrated Cyclometer, the combined information could
>>>>>be used to calculate how much energy was lost to rolling
>>>>>resistance and aerodynamic drag. Subtracting this loss from the
>>>>>potential gravitational energy converted into kinetic energy
>>>>>would obtain the amount of potential energy converted into heat
>>>>>during braking.
>
>
>>>>I think I sense a troll detection test. We can measure the
>>>>altitude change and derive the ft lbs of energy far better.
>
>
>>>You've missed the point of his suggestion. Yes, it is trivial to
>>>determine the input energy; what he proposes is to try and
>>>accurately determine the amount of that energy lost to air
>>>resistance and rolling resistance. That and the kinetic energy at
>>>the end of the run may be subtracted from the input energy to
>>>determine the energy that must necessarily have become hear under
>>>braking.
>
>
>>If my proposed experiment were successfully conducted, it would be
>>possible to determine the amount of energy that would need to be
>>dissipated by braking on a given descent. From Jobst Brandt's
>>proposed experimental data we could then determine the factor of
>>safety against tire blow-off for the descent in question. This could
>>further be combined with real-time GPS data and stored topographic
>>data to let the rider know the maximum safe tire pressure before
>>each descent.
>
>
> For which rider, clothing, ambient temperature, tire type, inflation
> pressure... Let's be practical. There is a concept to be
> investigated here rather than a recipe for descending. If you
> consider the variables involved, your proposal becomes undefinable.

Jobst Brandt is correct IF we use a small factor of safety. However, if
we assume a typical case of a rider on a standard diamond frame road
bike, using normal tires, wearing cycling short and jersey, and riding
"on the drops" we can reasonably estimate the losses from rolling
resistance and aerodynamic drag. We can then choose a factor of safety
that will depend on how risk adverse the rider is.

We could dispense with the GPS. The rider would simply use his/her
judgement to pick out particular descents in advance of the ride, and
then calculate the factor of safety against tire blow-off. If the factor
of safety were too low, the rider would simply plan to reduce tire
pressure in advance or to stop and cool the rims part way down.

An entirely different approach would be to build wireless temperature
and pressure transducers into the rim. When a certain threshold was
exceeded, an alarm would be triggered. The rider would then stop and
cool the rims. Liquid cooling when riding would be an option for anyone
with a full or partially full water bottle and decent aim.

--
Tom Sherman - Near Rock Island

 

[David Damerell]

begin quoting <[email protected]>:
>Tom Sherman writes:
>>dissipated by braking on a given descent. From Jobst Brandt's
>>proposed experimental data we could then determine the factor of
>>safety against tire blow-off for the descent in question. This could
>>further be combined with real-time GPS data and stored topographic
>>data to let the rider know the maximum safe tire pressure before
>>each descent.
>For which rider, clothing, ambient temperature, tire type, inflation
>pressure... Let's be practical.

Well, it would be practical to determine approximate values; to know that
for descent A there is nothing to worry about, but for descent B there is
cause for concern; or a particular rider or tandem team could have a
general idea of how steep and long a descent could be before there was a
need to worry.
--
David Damerell <[email protected]> Distortion Field!
Today is Second Mania, January.