Mavic Open Pro & Open Pro CD
RS
more expensive Open Pro CD rim vs. the standard Open Pro rim? One
LBS suggested the CD version didn't brake as well, other than that I can't
imagine a problem with the CD version?
Qui si parla Campagnolo
CD, meaning hard anodizing, can be prone to cracks around the eyelets
due to that hard anodizing. Treated and then the eyelets are
installed, which causes micro cracks, which 'can' lead to p[remature
cracking. BUT look at DT, MUCH better rim, the 1.1, double eyelet.
Braking, with machined sidewalls on both, is a non issue.
jim beam
> On Jun 17, 11:23�pm, RS <r_schil...@comcast.net> wrote:
>> From practical experience any advantage or disadvantages to the slightly
>> more expensive Open Pro CD rim vs. the standard Open Pro rim? �One
>> LBS suggested the CD version didn't brake as well, other than that I can't
>> imagine a problem with the CD version?
>
> CD, meaning hard anodizing, can be prone to cracks around the eyelets
> due to that hard anodizing.
yeah, people post pics of their cracked cd rims here all the time. not.
this is underinformed presumptive jobstian bullshit. peter, you should
know better by now. rim cracking is due to excess spoke tension and the
fundamental problem of using extrusions to make the rim hoop -
[anisotropy]. observe manufacturer spec on spoke tension and you'll
have no more problem that you would with any other open pro rim.
jim beam
from practical experience, they brake just fine - don't listen to the
fud you get on newsgroups propagated by people that criticize something
they've never used. no other disadvantage - they're no more susceptible
to cracking than any other open pro rim when the spokes are
over-tensioned. make sure therefore that the manufacturer's spoke
tension spec is properly observed.
other than that, if you're seeking wet weather wear resistance, skip
ahead to the ceramic rim - the cd does increase wear resistance, but not
hugely, and it does wear off. the ceramics are virtually wear proof.
Mike Jacoubowsky
news:ls6dnT5KeKKxlMTV...@speakeasy.net...
| Qui si parla Campagnolo wrote:
| >> From practical experience any advantage or disadvantages to the
slightly
| >> LBS suggested the CD version didn't brake as well, other than that I
can't
| >> imagine a problem with the CD version?
| >
| > CD, meaning hard anodizing, can be prone to cracks around the eyelets
| > due to that hard anodizing.
|
| yeah, people post pics of their cracked cd rims here all the time. not.
|
| this is underinformed presumptive jobstian bullshit. peter, you should
| know better by now. rim cracking is due to excess spoke tension and the
| fundamental problem of using extrusions to make the rim hoop -
| [anisotropy]. observe manufacturer spec on spoke tension and you'll
| have no more problem that you would with any other open pro rim.
|
|
| > Treated and then the eyelets are
| > installed, which causes micro cracks, which 'can' lead to p[remature
| > cracking. BUT look at DT, MUCH better rim, the 1.1, double eyelet.
| >
| > Braking, with machined sidewalls on both, is a non issue.
First, the question wasn't Mavic vs DT. Second, the DT hasn't been around
long enough to know if it will have issues. Third, rim cracking has, in
fact, been a major, not minor problem, ever since the hard anodizing came
into vogue. Whether there are other factors at play is a legit question,
since the hard anodizing may have come at the same time as subtle changes in
rim alloys. One thing's certain- back in the day, we'd see many wheels fail
due to denting. Denting is almost never seen with modern rims, but cracking
is. I think we've traded one problem for another, and I don't think it's
just anodizing at fault, but it's likely a contributor.
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
Michael Press
"Mike Jacoubowsky" <mik...@ix.netcom.com> wrote:
What you think is not backed by evidence.
How about finding some evidence that rim
alloys have changed in such a way as to
promote cracking, then come back with it.
Otherwise you are promoting a brand new
unsubstantiated rumor among all the others
floating around here.
--
Michael Press
Mike Jacoubowsky
>> long enough to know if it will have issues. Third, rim cracking has, in
>> fact, been a major, not minor problem, ever since the hard anodizing came
>> into vogue. Whether there are other factors at play is a legit question,
>> since the hard anodizing may have come at the same time as subtle changes
>> in
>> rim alloys. One thing's certain- back in the day, we'd see many wheels
>> fail
>> due to denting. Denting is almost never seen with modern rims, but
>> cracking
>> is. I think we've traded one problem for another, and I don't think it's
>> just anodizing at fault, but it's likely a contributor.
>
> What you think is not backed by evidence.
> How about finding some evidence that rim
> alloys have changed in such a way as to
> promote cracking, then come back with it.
> Otherwise you are promoting a brand new
> unsubstantiated rumor among all the others
> floating around here.
>
> --
> Michael Press
What's not backed up by evidence? I have a shop full of evidence. I have way
too much evidence, in fact!
Or are you talking specifically about the possibility that rim alloys have
changed over the years? That's really the only thing that hasn't come up in
the various discussions here, and I think it needs to be looked into. I've
seen non-anodized rims crack as well, just not nearly as many as with
anodized versions. But that could be due to sample size issues; since there
are far more anodized rims out there these days, you're not going to be as
likely to see a failure on a non-anodized rim. On the other hand, people who
know such things tell me that many rims which people believe not to have
been anodized, actually were.
It would be interesting to see someone do an analysis of the actual rim
material from past days to present.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
Qui si parla Campagnolo
> "jim beam" <spamvor...@bad.example.net> wrote in message
We have been building with DT for almost a year, probably in excess of
200 rims, w/o any problem whatsoever. Small sample to be sure but.....
As for the OP and if some have an issue with Jobst, they should say
so..I guess he did. He has more problem with Jobst that I have with
shimano and sram.
jim beam
<snip for clarity>
> I don't think it's
> just anodizing at fault, but it's likely a contributor.
given that there's no correlation between anodizing crack orientation
and rim crack orientation, saying that anodizing is "likely a
contributor" is about as useful as saying that vegetarianism is "likely
a contributor" to bicycle/suv impact fatalities. some dead bike riders
may indeed have been vegetarians, but it made no difference to their
mortality when the suv entered the equation.
Tom Kunich
news:Khk6k.10382$uE5....@flpi144.ffdc.sbc.com...
>
> It would be interesting to see someone do an analysis of the actual rim
> material from past days to present.
If you look at the specifications you'll see that nothing has changed in the
rim material since the mid-80's. What HAS changed is that they no longer
even try to make "light" rims as they did in the 60's and 70's.
400 grams is a light rim these days. Compare that to the 265 grams from
1980.
Tom Ace
>If you look at the specifications you'll see that nothing has changed
>in the rim material since the mid-80's. What HAS changed is that they
>no longer even try to make "light" rims as they did in the 60's and 70's.
>
>400 grams is a light rim these days. Compare that to the 265 grams from
>1980.
Are the 1980s rims you have in mind clincher or tubular rims?
265g was about the weight of a Fiamme yellow label tubular rim.
Someone please correct me if I'm wrong, but I thought many
tubular rims of that era were not extruded but rather formed
from sheet. I have noticed a seam running all the way around
the rim (in the middle of the surface the tire glues to) on
Mavic tubular rims from the 70s and 80s.
Tom Ace
carl...@comcast.net
Dear Mike & Tom,
Whether current rims are made from different materials than older
rims, Chalo thinks that current rims use different materials,
according to whether they're made by Sun, Mavic, Velocity, or Alex:
"I have not been able to determine the alloy composition of Sun rims.
The polished models seem pretty soft, which is to say they are
probably made from a weaker alloy than 6061-T6. On the other hand
they are quite ductile compared to recent Mavics. At the same
absolute strength, a ductile rim beats a brittle one every time."
"Most Mavic and Velocity rims use 6106 alloy, the weakest member of
the 6000 series of aluminum alloy (but one that makes pretty
extrusions). All Alex rims I know of use 6061-T6 alloy, which is
substantially stronger."
"A few Mavic rims, for instance the Open Pro, use some code-named
alloy which Mavic boasts to be "20% stronger!" or something to that
effect. To me, that means it might well be the same 6061-T6 alloy that
Alex sells for 1/4 the price."
http://groups.google.com/group/rec.bicycles.tech/msg/f69941baeb338cc6
Cheers,
Carl Fogel
andre...@aol.com
The move has been to more aerodynamic wheels with fewer spokes the
rims have taller profiles and are heavier and can work with less
spokes. I don't know an old mavic sew-up like the 280 or a fiamme
would do with 20 spokes. I'm not arguing that 20 spoke wheels are
better or that low or tall profile rims are better.
I still remember the days where you could lace a wheel and tighten the
spokes without worrying about running the nipples through the walls.
Nowadays, I have to be more careful and not use too much tension.
Tom Kunich
news:e2644774-a0da-4dd3...@w34g2000prm.googlegroups.com...
>
> Are the 1980s rims you have in mind clincher or tubular rims?
> 265g was about the weight of a Fiamme yellow label tubular rim.
I have a couple of 32 spoke Japanese clincher rims that are 270 grams and
after weighing them they are actually 265. There were Italian clincher rims
that were lighter. For instance - Mavic made a 280 gram and on a new mold
they were considerably lighter.
A Muzi
>> If you look at the specifications you'll see that nothing has changed
>> in the rim material since the mid-80's. What HAS changed is that they
>> no longer even try to make "light" rims as they did in the 60's and 70's.
>> 400 grams is a light rim these days. Compare that to the 265 grams from
>> 1980.
Tom Ace wrote:
> Are the 1980s rims you have in mind clincher or tubular rims?
> 265g was about the weight of a Fiamme yellow label tubular rim.
>
> Someone please correct me if I'm wrong, but I thought many
> tubular rims of that era were not extruded but rather formed
> from sheet. I have noticed a seam running all the way around
> the rim (in the middle of the surface the tire glues to) on
> Mavic tubular rims from the 70s and 80s.
AFAIK Mavic, Fiamme, SuperChamp Weinmann etc were all extruded and
pinned at the seam opposite the valve with a shaped insert inside.
(even Harlan Meyer's ultralight sub-200g Hi-E rims were indeed extruded
and wrapped then seamed with rivets. There's one near me right now as it
happens)
The lightest clincher of the classic era AFAIK was the 370g Araya CTL.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
** Posted from http://www.teranews.com **
A Muzi
>> Are the 1980s rims you have in mind clincher or tubular rims?
>> 265g was about the weight of a Fiamme yellow label tubular rim.
Tom Kunich wrote:
> I have a couple of 32 spoke Japanese clincher rims that are 270 grams
> and after weighing them they are actually 265. There were Italian
> clincher rims that were lighter. For instance - Mavic made a 280 gram
> and on a new mold they were considerably lighter.
270g clincher? Which model?
In 700C size, 1980s books show Araya lists nothing below the 370 gram
CTL, Ukai down to 405g only, model #20A.
Michael Press
"Mike Jacoubowsky" <Mi...@ChainReaction.com> wrote:
> >> First, the question wasn't Mavic vs DT. Second, the DT hasn't been around
> >> long enough to know if it will have issues. Third, rim cracking has, in
> >> fact, been a major, not minor problem, ever since the hard anodizing came
> >> into vogue. Whether there are other factors at play is a legit question,
> >> since the hard anodizing may have come at the same time as subtle changes
> >> in
> >> rim alloys. One thing's certain- back in the day, we'd see many wheels
> >> fail
> >> due to denting. Denting is almost never seen with modern rims, but
> >> cracking
> >> is. I think we've traded one problem for another, and I don't think it's
> >> just anodizing at fault, but it's likely a contributor.
> >
> > What you think is not backed by evidence.
> > How about finding some evidence that rim
> > alloys have changed in such a way as to
> > promote cracking, then come back with it.
> > Otherwise you are promoting a brand new
> > unsubstantiated rumor among all the others
> > floating around here.
>
> What's not backed up by evidence? I have a shop full of evidence. I have way
> too much evidence, in fact!
>
> Or are you talking specifically about the possibility that rim alloys have
> changed over the years?
I think so, since I wrote
> evidence that rim
> alloys have changed in such a way as to
> promote cracking
You introduced the topic with
> Whether there are other factors at play is a legit question,
> since the hard anodizing may have come at the same time as subtle changes in
> rim alloys.
> That's really the only thing that hasn't come up in
> the various discussions here, and I think it needs to be looked into.
Then look into it. Floating an open ended question in rbt
is an invitation for folks to take the answer as they please.
You know it happens.
--
Michael Press
carl...@comcast.net
wrote:
>> "Tom Ace" <tom...@gmail.com> wrote
>>> Are the 1980s rims you have in mind clincher or tubular rims?
>>> 265g was about the weight of a Fiamme yellow label tubular rim.
>
>Tom Kunich wrote:
>> I have a couple of 32 spoke Japanese clincher rims that are 270 grams
>> and after weighing them they are actually 265. There were Italian
>> clincher rims that were lighter. For instance - Mavic made a 280 gram
>> and on a new mold they were considerably lighter.
>
>270g clincher? Which model?
>In 700C size, 1980s books show Araya lists nothing below the 370 gram
>CTL, Ukai down to 405g only, model #20A.
Dear Andrew,
Heck, I'm having trouble finding 275 gram clinchers from any year on
the Weight Weenies list:
http://weightweenies.starbike.com/listings/components.php?type=rims&sortby=real
The 700c clinchers seem to start around 350 grams.
Maybe the list leaves out a lot of lightweight clincher rims?
Cheers,
Carl Fogel
Lou Holtman
275 grams and they were rideable? Hard to believe.
Lou
Tom Ace
> Tom Ace wrote:
> > Are the 1980s rims you have in mind clincher or tubular rims?
> > 265g was about the weight of a Fiamme yellow label tubular rim.
>
> > Someone please correct me if I'm wrong, but I thought many
> > tubular rims of that era were not extruded but rather formed
> > from sheet. I have noticed a seam running all the way around
> > the rim (in the middle of the surface the tire glues to) on
> > Mavic tubular rims from the 70s and 80s.
>
> AFAIK Mavic, Fiamme, SuperChamp Weinmann etc were all extruded and
> pinned at the seam opposite the valve with a shaped insert inside.
I put a pic of a mid-1980s Mavic GP4 tubular rim on the web at
http://minortriad.com/gp4.jpg
The seam I'm referring to is a small ridge on the top surface,
and there's a more pronounced blob on the underside of the
same section (visible through the valve hole).
If it's not a seam, what is it? I haven't seen anything like
it on the (extruded) clincher rims I've had.
Tom Ace
Tom Kunich
news:485ad98f$1...@news4us.nl...
>
> 275 grams and they were rideable? Hard to believe.
My mistake - the Araya's were 370 grams but the one's I had were weighed
lighter than that though not much.
But Mavic had some 280 gram clinchers because I bought a set from a friend
and although he claimed that you couldn't ride them if you weighed over 150
lbs I rode them all the time at 200 lbs. The wheels were 32 spoke and didn't
flex noticeably.
jobst....@stanfordalumni.org
>>> Are the 1980s rims you have in mind clincher or tubular rims?
>>> 265g was about the weight of a Fiamme yellow label tubular rim.
>>> Someone please correct me if I'm wrong, but I thought many tubular
>>> rims of that era were not extruded but rather formed from sheet.
>>> I have noticed a seam running all the way around the rim (in the
>>> middle of the surface the tire glues to) on Mavic tubular rims
>>> from the 70s and 80s.
>> AFAIK Mavic, Fiamme, Super Champ, Weinmann, etc were all extruded
>> and pinned at the seam opposite the valve with a shaped insert.
> I put a pic of a mid-1980s Mavic GP4 tubular rim on the web at:
> The seam I'm referring to is a small ridge on the top surface, and
> there's a more pronounced blob on the underside of the same section
> (visible through the valve hole).
> If it's not a seam, what is it? I haven't seen anything like it on
> the (extruded) clincher rims I've had.
From what I have seen, those are artifacts produced by a floating core
extrusion die and constitute a full depth weld in a neutral plane.
Jobst Brandt
Mike Jacoubowsky
>> Whether there are other factors at play is a legit question,
>> since the hard anodizing may have come at the same time as subtle changes
>> in
>> rim alloys.
>
>> That's really the only thing that hasn't come up in
>> the various discussions here, and I think it needs to be looked into.
>
> Then look into it. Floating an open ended question in rbt
> is an invitation for folks to take the answer as they please.
> You know it happens.
I'm not just floating an open-ended question for fun. I'm fielding it in the
hope that someone might *know* if that's the case (that alloys have changed
over the years). I know that at least one manufacturer has used various
different alloys of 6000-series aluminum, but that was quite some time ago,
and I'm not privvy to any testing data that may have been done at the time.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
"Michael Press" <rub...@pacbell.net> wrote in message
news:rubrum-E82B98....@news.sf.sbcglobal.net...
Tim McTeague
"Qui si parla Campagnolo" <pe...@vecchios.com> wrote in message
news:6834df07-5ca2-45fb...@v1g2000pra.googlegroups.com...
Joe Young http://www.youngwheels.com/ is also a big fan of DT RR1.1 rims
and he seems to know a thing or two about wheelbuilding.
Tim McTeague
jim beam
you absolute bullshitter! "a full depth weld in a neutral plane" of an
extrusion??? jobst, that is the most outstanding piece of made-up,
suppositional, pathetic attempt at trying to sound relevant, CRAP that
i've ever seen from you. and you've uttered some real peaches in the
past. absolutely outrageous.
jim beam
it's a telltale. all mavic rims have them. if there's a problem with
the extrusion, the telltale will disappear because it's a "fine" surface
feature indicating insufficient material flow.
and all rims are extruded. no "full depth weld in a neutral plane"!!!
jim beam
it's been raised before, and is relevant.
> I've
> seen non-anodized rims crack as well, just not nearly as many as with
> anodized versions. But that could be due to sample size issues; since there
> are far more anodized rims out there these days, you're not going to be as
> likely to see a failure on a non-anodized rim. On the other hand, people who
> know such things tell me that many rims which people believe not to have
> been anodized, actually were.
indeed. mavic ma2 for instance.
>
> It would be interesting to see someone do an analysis of the actual rim
> material from past days to present.
i think chas** has access to metallography. i don't these days.
Morten Reippuert Knudsen
> other than that, if you're seeking wet weather wear resistance, skip
> ahead to the ceramic rim - the cd does increase wear resistance, but
> not hugely, and it does wear off. the ceramics are virtually wear
> proof.
I've got the Ceramice version and i adore them. braking in the wet (we
got a lot of that in denmark) with both campy and green swissstop pads
is exelent and they look like new though having ridden almost two years
(aslo durring winter time).
While they are great in wet weather they are even better when decenting
Galibier with 80km/t or the tricky turns down col du Mollard. Besides
braking performance it's very comforting to know that you don't have to
fear a blown tire due to hot rims
--
mvh. Morten Reippuert Knudsen
"Besides, if you can't get a decent kernal panic
or two in a month, what's the point of living?"
jobst....@stanfordalumni.org
>>> Are the 1980s rims you have in mind clincher or tubular rims?
>>> 265g was about the weight of a Fiamme yellow label tubular rim.
>>> Someone please correct me if I'm wrong, but I thought many tubular
>>> rims of that era were not extruded but rather formed from sheet.
>>> I have noticed a seam running all the way around the rim (in the
>>> middle of the surface the tire glues to) on Mavic tubular rims
>>> from the 70s and 80s.
>> AFAIK Mavic, Fiamme, Super Champion, Weinmann etc were all extruded
>> and pinned at the seam opposite the valve with a shaped insert
>> inside.
> I put a pic of a mid-1980s Mavic GP4 tubular rim on the web at
> The seam I'm referring to is a small ridge on the top surface, and
> there's a more pronounced blob on the underside of the same section
> (visible through the valve hole).
> If it's not a seam, what is it? I haven't seen anything like it on
> the (extruded) clincher rims I've had.
A floating core in an extrusion is roughly like a jet engine pod on an
air liner, hanging in the extrusion die where the slender arm supports
the core to remain precisely located and causes a split in the shape
that closes after passing. That closure is essentially a full depth
"weld" leaving a bit of flash or a negative (groove) at that place in
the extrusion.
Jobst Brandt
jobst....@stanfordalumni.org
>> other than that, if you're seeking wet weather wear resistance,
>> skip ahead to the ceramic rim - the cd does increase wear
>> resistance, but not hugely, and it does wear off. the ceramics are
>> virtually wear proof.
> I've got the Ceramice version and i adore them. braking in the wet
> (we got a lot of that in denmark) with both campy and green
> swissstop pads is exelent and they look like new though having
> ridden almost two years (aslo durring winter time).
> While they are great in wet weather they are even better when
> decenting Galibier with 80km/t or the tricky turns down col du
> Mollard. Besides braking performance it's very comforting to know
> that you don't have to fear a blown tire due to hot rims
Where does the braking energy go if it isn't heat? I don't understand
what you think is occurring when braking while descending. I assume
they are aluminum rims with ceramic coating. Heat generated by brakes
is the same regardless of rim or brake pad. It is the kinetic energy
of rider and bicycle.
Who makes thse rims and what is the model name?
> "Besides, if you can't get a decent kernal panic or two in a month,
> what's the point of living?"
What is a "decent kernal panic"?
Jobst Brandt
pgr...@gmail.com
The ceramic line is basically the same as a CD (anodized, welded and
turned smooth at the joint) rim with ceramic bonded to the braking
surface.
I use them both on my winter and loaded touring bikes, with the same
results as this poster talked about. No real heat up, no fading,
etc. They brake almost the same in the wet as the dry, which is
impressive.
I've used these for >10 years now, with one set pulling through at the
eylets, and that was a set of touring wheels that went thousands of
loaded touring miles and many years.
It is interesting to speculate what happens to the heat with these
rims, but you can definitely touch them (even on our tandem) after a
long descent and they're just warm to the touch, not hot at all.
They're well worth their cost (roughly double a regular rim) both in
terms of being able to stop, consistently, and in terms of sidewall
wear. I usually go through a pair when I've hit too many holes riding
at night or similar...
-pete
Dan O
> Morten Reippuert Knudsen wrote:
<snip the On-topic stuff>
>
> > "Besides, if you can't get a decent kernal panic or two in a month,
> > what's the point of living?"
>
> What is a "decent kernal panic"?
>
http://en.wikipedia.org/wiki/Kernel_Panic (?)
jobst....@stanfordalumni.org
>>> "Besides, if you can't get a decent kernal panic or two in a month,
>>> what's the point of living?"
>> What is a "decent kernal panic"?
http://en.wikipedia.org/wiki/Kernel_Panic (?)
I don't see the connection between computer code and bicycle brakes
and life in general. The association is cryptic jargon to me.
Jobst Brandt
Tom Kunich
news:0a6b7f0d-4cfa-4747...@r37g2000prm.googlegroups.com...
Thanks for that information about the ceramic rims Peter.
jobst....@stanfordalumni.org
>>>> other than that, if you're seeking wet weather wear resistance,
>>>> skip ahead to the ceramic rim - the cd does increase wear
>>>> resistance, but not hugely, and it does wear off. the ceramics
>>>> are virtually wear proof.
>>> I've got the Ceramic version and i adore them. braking in the
>>> wet (we got a lot of that in Denmark) with both campy and green
>>> swissstop pads is excellent and they look like new though having
>>> ridden almost two years (also during winter time). While they
>>> are great in wet weather they are even better when descending
>>> Galibier with 80km/t or the tricky turns down col du Mollard.
>>> Besides braking performance it's very comforting to know that you
>>> don't have to fear a blown tire due to hot rims
>> Where does the braking energy go if it isn't heat? I don't
>> understand what you think is occurring when braking while
>> descending. I assume they are aluminum rims with ceramic coating.
>> Heat generated by brakes is the same regardless of rim or brake
>> pad. It is the kinetic energy of rider and bicycle.
>> Who makes these rims and what is the model name?
> The ceramic line is basically the same as a CD (anodized, welded and
> turned smooth at the joint) rim with ceramic bonded to the braking
> surface.
> I use them both on my winter and loaded touring bikes, with the same
> results as this poster talked about. No real heat up, no fading,
> etc. They brake almost the same in the wet as the dry, which is
> impressive.
Yes...? so where does the heat go and what sort of brake pads do they
require? Do these pads work on aluminum as well? I keep getting the
feeling that this is all secret and that non-members don't get any
details.
> I've used these for >10 years now, with one set pulling through at
> the eyelets, and that was a set of touring wheels that went
> thousands of loaded touring miles and many years.
My touring wheels go about 10,000 miles before the braking surface
wears down to 0.5mm and require a new rim. I also have rims that are
30 years old that are fine, but then I haven't ridden them in more
than 20 years. Years don't tell me much about rim wear.
> It is interesting to speculate what happens to the heat with these
> rims, but you can definitely touch them (even on our tandem) after a
> long descent and they're just warm to the touch, not hot at all.
> They're well worth their cost (roughly double a regular rim) both in
> terms of being able to stop, consistently, and in terms of sidewall
> wear. I usually go through a pair when I've hit too many holes
> riding at night or similar...
The heat did not go into the pad, they being insulators and have no
volume or surface f significance. That your rims are cool to the
touch must be because you touch them on the ceramic surface, an
insulator. You should feel if the base metal of the rim is hot,
possibly between spokes. Not knowing how these super rims look, what
the brand name and model is, I can make little of what is being said
here.
Jobst Brandt
jobst....@stanfordalumni.org
>> Who makes these rims and what is the model name?
> The ceramic line is basically the same as a CD (anodized, welded and
> turned smooth at the joint) rim with ceramic bonded to the braking
> surface.
So these are just Mavic Open Pro CD rims:
http://tinyurl.com/54lrlu
http://tinyurl.com/4f5kdj
* Maxtal with SUP welding reduces weight and vibrations while adding
strength
* Eyeleted design enhances strength around the spoke area and further
lightens the rim profile
* Ceramic 2 coating provides the incredible stopping power you need
when you're going fast
At $100 (Specialized) per rim you probably believe these claims. As
you say, the "enhances strength around the spoke area" caused spoke
pull-out while wet and dry braking is improved. That "welding reduces
weight and vibrations" also requires faith. My ancient Mavic MA-2
rims are dead steady at over 60mph on steep descents or I wouldn't let
the bicycle reach such speeds.
Jobst Brandt
Michael Press
<0a6b7f0d-4cfa-4747...@r37g2000prm.googlegroups.com>,
pgr...@gmail.com wrote:
> On Jun 20, 11:48 am, jobst.bra...@stanfordalumni.org wrote:
> > Morten Reippuert Knudsen wrote:
> > >> other than that, if you're seeking wet weather wear resistance,
> > >> skip ahead to the ceramic rim - the cd does increase wear
> > >> resistance, but not hugely, and it does wear off. the ceramics are
> > >> virtually wear proof.
> > > I've got the Ceramice version and i adore them. braking in the wet
> > > (we got a lot of that in denmark) with both campy and green
> > > swissstop pads is exelent and they look like new though having
> > > ridden almost two years (aslo durring winter time).
> > > While they are great in wet weather they are even better when
> > > decenting Galibier with 80km/t or the tricky turns down col du
> > > Mollard. Besides braking performance it's very comforting to know
> > > that you don't have to fear a blown tire due to hot rims
> >
> > Where does the braking energy go if it isn't heat? I don't understand
> > what you think is occurring when braking while descending. I assume
> > they are aluminum rims with ceramic coating. Heat generated by brakes
> > is the same regardless of rim or brake pad. It is the kinetic energy
> > of rider and bicycle.
> >
> > Who makes thse rims and what is the model name?
> >
> > > "Besides, if you can't get a decent kernal panic or two in a month,
> > > what's the point of living?"
> >
> > What is a "decent kernal panic"?
>
> The ceramic line is basically the same as a CD (anodized, welded and
> turned smooth at the joint) rim with ceramic bonded to the braking
> surface.
> I use them both on my winter and loaded touring bikes, with the same
> results as this poster talked about. No real heat up, no fading,
> etc. They brake almost the same in the wet as the dry, which is
> impressive.
> I've used these for >10 years now, with one set pulling through at the
> eylets, and that was a set of touring wheels that went thousands of
> loaded touring miles and many years.
> It is interesting to speculate what happens to the heat with these
> rims, but you can definitely touch them (even on our tandem) after a
> long descent and they're just warm to the touch, not hot at all.
> They're well worth their cost (roughly double a regular rim) both in
> terms of being able to stop, consistently, and in terms of sidewall
> wear. I usually go through a pair when I've hit too many holes riding
> at night or similar...
Some places the heat can go.
Ablation of the ceramic
Ablation of the brake pad
Surface of the ceramic gets very hot at the pad contact patch,
then dumps the heat into the wind stream.
--
Michael Press
Michael Press
jobst....@stanfordalumni.org wrote:
Failure of an operating at a fundamental level (the kernel.)
When I did QA work the goal was kernel panics.
--
Michael Press
jim beam
> Tom Ace wrote:
>
>>>> Are the 1980s rims you have in mind clincher or tubular rims?
>>>> 265g was about the weight of a Fiamme yellow label tubular rim.
>
>>>> Someone please correct me if I'm wrong, but I thought many tubular
>>>> rims of that era were not extruded but rather formed from sheet.
>>>> I have noticed a seam running all the way around the rim (in the
>>>> middle of the surface the tire glues to) on Mavic tubular rims
>>>> from the 70s and 80s.
>
>>> AFAIK Mavic, Fiamme, Super Champion, Weinmann etc were all extruded
>>> and pinned at the seam opposite the valve with a shaped insert
>>> inside.
>
>> I put a pic of a mid-1980s Mavic GP4 tubular rim on the web at
>
> http://minortriad.com/gp4.jpg
>
>> The seam I'm referring to is a small ridge on the top surface, and
>> there's a more pronounced blob on the underside of the same section
>> (visible through the valve hole).
>
>> If it's not a seam, what is it? I haven't seen anything like it on
>> the (extruded) clincher rims I've had.
>
> A floating core in an extrusion is roughly like a jet engine pod on an
> air liner, hanging in the extrusion die where the slender arm supports
> the core to remain precisely located and causes a split in the shape
> that closes after passing.
1. whether or not the extrusion plug floats is utterly irrelevant. but
you'd not have said it if you knew what you were talking about.
2. the "closes after passing" is true for the whole extrusion - there's
no one part that is any seam. but you'd not have said it if you knew
what you're talking about.
> That closure is essentially a full depth
> "weld" leaving a bit of flash or a negative (groove) at that place in
> the extrusion.
see above. bullshitter.
jim beam
jobst, where do you get off? criticizing, from a position of ignorance,
something you've never used just doesn't cut it. because maybe, just
maybe, THERE'S SOMETHING YOU DON'T KNOW AND YOUR CRITICISM IS UNFOUNDED
BULLSHIT.
jim beam
i've yet to see any association between "jobst brandt" and engineering
in general.
Jakob Bartholdy Bruun
>
> I've got the Ceramice version and i adore them. braking in the wet (we
> got a lot of that in denmark) with both campy and green swissstop pads
> is exelent and they look like new though having ridden almost two years
> (aslo durring winter time).
>
A short digression
Morten, how do the green swisstop pads wear compared to campy on your
rims? I have the same rims (and yes - they do enhance braking) and I
find that my campy pads wear pretty fast on the ceramic rims.
- jakob
pgr...@gmail.com
>
> - Show quoted text -
I typically get 2-3K/year/bike.
My tourer gets more/less some years, depending on length of tour that
year. Less lately since we're towing a toddler on tour, days are
shorter.
I agree, years don't mean much, but miles do. I typically beat up a
rim prior to going through the sidewalls. This is on my winter bike
here as well, in the Seattle area, where winter road-grit is the norm,
not the exception.
I've tried feeling outside the ceramic, and again, they're not really
that hot. I've descended on a tandem with non-ceramics, and on
touring bikes, and I know how hot the rims get in these circumstances.
Nothing that secret about them, Mavic mapes the Open series with
ceramic, as do a couple of other manuf. periodically. You just don't
see 'em at your typical LBS, sinc they're roughly double the cost up-
front. I think people have trouble seeing the value.
The first time you come to a quick stop on a blazing-fast descent in a
big rainstorm (at least as fast as tire-friction will let you), the
value speaks for itself, IMHO.
-pete
jobst....@stanfordalumni.org
> I typically get 2-3K/year/bike. My tourer gets more/less some
> years, depending on length of tour that year. Less lately since
> we're towing a toddler on tour, days are shorter. I agree, years
> don't mean much, but miles do. I typically beat up a rim prior to
> going through the sidewalls. This is on my winter bike here as
> well, in the Seattle area, where winter road-grit is the norm, not
> the exception.
> I've tried feeling outside the ceramic, and again, they're not
> really that hot. I've descended on a tandem with non-ceramics, and
> on touring bikes, and I know how hot the rims get in these
> circumstances.
I think that is an unclear temperature measure because ceramic is an
insulator and may not reveal the temperature of the aluminum rim as
readily as a bare aluminum rim.
> Nothing that secret about them, Mavic makes the Open series with
> ceramic, as do a couple of others periodically. You just don't see
> 'em at your typical LBS, since they're roughly double the cost up-
> front. I think people have trouble seeing the value. The first
> time you come to a quick stop on a blazing-fast descent in a big
> rainstorm (at least as fast as tire-friction will let you), the
> value speaks for itself, IMHO.
I read such endorsements here and try to explain why this should
happen. As I explained, braking does not become effective until the
rim is mostly dry. A ceramic rim can get a hot surface more quickly
than a bare aluminum rim. Therefore, it can begin braking sooner and
with less effort than bare aluminum.
I'm not sure this is what occurs, but it is an explanation. I come to
this because I rode wooden rims that braked well when initially wet.
They also develop a hot surface because they don't conduct heat, but
to make up for that, I found they ate up brake blocks by melting them.
I don't think you can have it both ways. That's why I ask where the
heat is supposed to go and how does one get rid of it. No one has
approached that matter and we seem to leave it a mystery. I am
skeptical because in the early days of hard anodized rims (effectively
ceramic coated) brakes worked poorly because the conventional pads
melted.
We need something more than "I use them and like them" to assess how
good they are. I've descended many miles in rain with slightly
reduced performance on bare aluminum rims, and complete brake failure
when snow piled up on the inner radius of Fiamme road rims and watered
the braking surface until all snow had melted and run off.
Jobst
jim beam
electrical insulator does not mean thermal insulator. take diamond for
example. alumina is not too shabby a thermal conductor either, and
guess what, the ceramic used here is substantially alumina. whodathunkit.
>
>> Nothing that secret about them, Mavic makes the Open series with
>> ceramic, as do a couple of others periodically. You just don't see
>> 'em at your typical LBS, since they're roughly double the cost up-
>> front. I think people have trouble seeing the value. The first
>> time you come to a quick stop on a blazing-fast descent in a big
>> rainstorm (at least as fast as tire-friction will let you), the
>> value speaks for itself, IMHO.
>
> I read such endorsements here and try to explain why this should
> happen. As I explained, braking does not become effective until the
> rim is mostly dry.
than you've not used one of these rims then jobst! why don't you ever
restrict your blathering to subjects where you actually /know/ what's
happening rather than merely supposing?
> A ceramic rim can get a hot surface more quickly
> than a bare aluminum rim. Therefore, it can begin braking sooner and
> with less effort than bare aluminum.
aren't you one of the people that told us braking depended on coolness,
not hotness?
>
> I'm not sure this is what occurs, but it is an explanation.
so why do you write in definitive terms? "braking does not become
effective" for example.
> I come to
> this because I rode wooden rims that braked well when initially wet.
> They also develop a hot surface because they don't conduct heat, but
> to make up for that, I found they ate up brake blocks by melting them.
and guess what, we have specialized brakes pad materials available for
ceramic rims! whodathunkit.
>
> I don't think you can have it both ways. That's why I ask where the
> heat is supposed to go and how does one get rid of it. No one has
> approached that matter and we seem to leave it a mystery. I am
> skeptical because in the early days of hard anodized rims (effectively
> ceramic coated) brakes worked poorly because the conventional pads
> melted.
why didn't mine?
>
> We need something more than "I use them and like them" to assess how
> good they are.
"we"??? /you/ actually buying some and bothering to use them might be a
place to start!!! how long have they been out now? 10 years? more?
> I've descended many miles in rain with slightly
> reduced performance on bare aluminum rims, and complete brake failure
> when snow piled up on the inner radius of Fiamme road rims and watered
> the braking surface until all snow had melted and run off.
[yawn].
Michael Press
jobst....@stanfordalumni.org wrote:
> I don't think you can have it both ways. That's why I ask where the
> heat is supposed to go and how does one get rid of it. No one has
> approached that matter and we seem to leave it a mystery. I am
> skeptical because in the early days of hard anodized rims (effectively
> ceramic coated) brakes worked poorly because the conventional pads
> melted.
I did.
<rubrum-BBB503....@news.sf.sbcglobal.net>
--
Michael Press
jobst....@stanfordalumni.org
>> I don't think you can have it both ways. That's why I ask where
>> the heat is supposed to go and how does one get rid of it. No one
>> has approached that matter and we seem to leave it a mystery. I am
>> skeptical because in the early days of hard anodized rims
>> (effectively ceramic coated) brakes worked poorly because the
>> conventional pads melted.
> I did.
Pardon my failure to understand, but what did you do. "I did" leaves
me guessing.
Jobst Brandt
Michael Press
jobst....@stanfordalumni.org wrote:
When you replied you removed from the quoted material
the Message-ID of the message where I suggested mechanisms
for dissipation of mechanical energy on those rims.
--
Michael Press
jobst....@stanfordalumni.org
>>>> I don't think you can have it both ways. That's why I ask where
>>>> the heat is supposed to go and how does one get rid of it. No
>>>> one has approached that matter and we seem to leave it a mystery.
>>>> I am skeptical because in the early days of hard anodized rims
>>>> (effectively ceramic coated) brakes worked poorly because the
>>>> conventional pads melted.
>>> I did.
>> Pardon my failure to understand, but what did you do. "I did"
>> leaves me guessing.
> When you replied you removed from the quoted material the Message-ID
> of the message where I suggested mechanisms for dissipation of
> mechanical energy on those rims.
rubrum-BBB503....@news.sf.sbcglobal.net
I don't know what to do with this reference. Please explain or copy
what you wrote there to this forum.
Jobst Brandt
Tom Kunich
news:rubrum-92C07B....@news.sf.sbcglobal.net...
Actually that looks like an email address.
Michael Press
Except for the server named news.sf.sbcglobal.net
that tells you it is a an nntp server, not smtp.
You can look it up.
-- Casey Stengel
--
Michael Press
Michael Press
jobst....@stanfordalumni.org wrote:
It is in this thread. You did not think it was worthy of
comment the first time, so we'll just forget about it.
--
Michael Press
jobst....@stanfordalumni.org
>>>>> I did.
rubrum-BBB503....@news.sf.sbcglobal.net
I have no idea what his link or how to use it. In another response
you wrote:
# Except for the server named news.sf.sbcglobal.net
# that tells you it is a an nntp server, not smtp.
#You can look it up.
Please explain what I can do with:
rubrum-BBB503....@news.sf.sbcglobal.net
I Google searched and found many nntp references but no instructions
on how to use it. Entering the above line does nothing from here.
Jobst Brandt
carl...@comcast.net
Dear Jobst,
With a newsreader like Forte Free Agent, clicking on the link will pop
up a message that the link is either an email-address or a message-id,
let you choose which (or make an educated guess for you), and take you
to the message.
Here's a link to the post, so you can get back to the subject:
http://groups.google.com/group/rec.bicycles.tech/msg/96301b17ae9cc7c1
Cheers,
Carl Fogel
jobst....@stanfordalumni.org
http://groups.google.com/group/rec.bicycles.tech/msg/96301b17ae9cc7c1
# Some places the heat can go.
# Ablation of the ceramic
# Ablation of the brake pad
# Surface of the ceramic gets very hot at the pad contact patch,
# then dumps the heat into the wind stream.
None of the above methods is realistic or useful as is apparent by
that no motor vehicle makes use of them. Having worked in designing
brakes for production and racing cars, none of these were considered.
I take it this is a put-on so I rather discuss practical aspects of
braking instead of humoring someone with supposed comedy.
Jobst Brandt
jim beam
> Michael Press wrote in:
>
> http://groups.google.com/group/rec.bicycles.tech/msg/96301b17ae9cc7c1
>
> # Some places the heat can go.
>
> # Ablation of the ceramic
> # Ablation of the brake pad
> # Surface of the ceramic gets very hot at the pad contact patch,
> # then dumps the heat into the wind stream.
>
> None of the above methods is realistic or useful as is apparent by
> that no motor vehicle makes use of them.
really? that's an extraordinary claim given that my brake pads ablate
each time i apply them! my brakes dump heat each time i apply them too!
> Having worked in designing
> brakes for production and racing cars, none of these were considered.
extraordinary. how many months did you work for porsche jobst? and
what exactly do the weasel words "working in designing" mean as opposed
to plain old "designing"? did you actually design or did you not? if
so, exactly what?
> I take it this is a put-on so I rather discuss practical aspects of
> braking instead of humoring someone with supposed comedy.
we'd /love/ for you to actually discuss the practical aspects!
preferably with numbers and from a position of experience. actually
using ceramic rims would be a dandy place for you to start. all you've
done so far is allude to something on which you're not prepared to
disclose detail, and scoff. oh, and evidence that you don't really
understand what you're talking about given the above statements.
Morten Reippuert Knudsen
> A short digression
> Morten, how do the green swisstop pads wear compared to campy on your
> rims? I have the same rims (and yes - they do enhance braking) and I
> find that my campy pads wear pretty fast on the ceramic rims.
The green swissstop lasts 3x longer than campys - however i have only
worn two sets on the ceramic rims (one of each).. My comparison may
not be fair.
If rims and pads are newly cleaned he campy pads has better braking
performance in dry weather but because of the wear, especially in rain,
pads and rims quickly picks up a lot of dust witch degrades breaking
performance significantly.
However campy pads on ceramic rims picks up less dust than campy pads
on aluminum rims. The green swissstop on the ceramic hardly pics up
dust at all witch means that i almost never clean pads and rims and
braking performance is almost the same regardless of conditions.
I prefer the green swissstop because of their low maintanence (wear +
cleaning) and ability to maintain braking power in rain and on long
decents.
--
mvh. Morten Reippuert Knudsen
jakob bruun
> The green swissstop lasts 3x longer than campys - however i have only
> worn two sets on the ceramic rims (one of each).. My comparison may not
> be fair.
>
<snip>
>
> I prefer the green swissstop because of their low maintanence (wear +
> cleaning) and ability to maintain braking power in rain and on long
> decents.
>
Thank you. I think that I will give the green swisstops a try when the
need for new pads arises.
- jakob
jobst....@stanfordalumni.org
>> A short digression Morten, how do the green swissstop pads wear
>> compared to campy on your rims? I have the same rims (and yes -
>> they do enhance braking) and I find that my campy pads wear pretty
>> fast on the ceramic rims.
> The green swissstop lasts 3x longer than campys - however I have
> only worn two sets on the ceramic rims (one of each)... My
> comparison may not be fair.
> If rims and pads are newly cleaned he campy pads has better braking
> performance in dry weather but because of the wear, especially in
> rain, pads and rims quickly picks up a lot of dust witch degrades
> breaking performance significantly.
> However campy pads on ceramic rims picks up less dust than campy
> pads on aluminum rims. The green swissstop on the ceramic hardly
> pics up dust at all witch means that i almost never clean pads and
> rims and braking performance is almost the same regardless of
> conditions.
> I prefer the green swissstop because of their low maintenance (wear
> + cleaning) and ability to maintain braking power in rain and on
> long descents.
This sounds interesting. I am still unclear about where the energy
goes having only experienced aluminum rims at more than boiling water
temperatures on alpine descents.
http://www.helvetiasports.com/HSP/HelvetiaSports.aspx
http://www.paloaltobicycles.com/alps_photos/i49.html
Jobst Brandt
jim beam
tell us jobst, given that the latent heat of vaporization for a gram of
water is 2260 J g^-1
http://en.wikipedia.org/wiki/Latent_heat
and the specific heat capacity of aluminum is only 0.897 J g^−1 K^−1
http://en.wikipedia.org/wiki/Heat_capacity#Heat_capacity
how hot and how heavy do you think you think your rims need to be to
achieve what you allege? given that your rims also have nice chilly air
blowing over than and all...