gritty road brakes
Mike
the front braking had that kind of gritty rubbing sound...indeed,
there were several particles of something embedded in each of the
front pads. It almost looked like aluminum, as if from the rim, but
that didn't make sense to me. I've never given much thought to this
kind of thing but the number of particles got me thinking: Is it
common to get stuff embedded in the brake pads, to the extent that
prying it out is a routine part of bike maintenance, or is my
experience atypical (I've never really noticed it before)? I presume
it's just grit from the road, but if not, do I have a rim problem
(Dura-Ace wheels)? Is it correct to conclude that softer pad compounds
are easier on the rims but also more susceptible to acquiring little
rim-eating fragments? Thanks.....
Mike
Phil Brown
>Toward the end of a ride this morning on dry pavement I noticed that
>the front braking had that kind of gritty rubbing sound...indeed,
>there were several particles of something embedded in each of the
>front pads. It almost looked like aluminum, as if from the rim, but
>that didn't make sense to me.
Bingo. Very common.
Phil Brown
Dion Dock
-Dion
"Mike" <mv...@webaccess.net> wrote in message
news:eb8c4432.03080...@posting.google.com...
Pete Grey
They last 3-4 times the life of regular alluminum surface rims (as long as
you don't beat them up by running into things), brake better, and there none
of that alluminum oxide build-up when you go to change flats.
I've been using them for over 10 years, I don't understand why more people
don't have them. The initial outlay is 2-3 times as much, but they pay for
themselves in the long run.
-pete
"Mike" <mv...@webaccess.net> wrote in message
news:eb8c4432.03080...@posting.google.com...
Terry Morse
> If you go with ceramic (coated) rims, anything goes, pad-wise.
Not true at all, see the FAQ below for why.
> They last 3-4 times the life of regular alluminum surface rims (as long as
> you don't beat them up by running into things), brake better, and there none
> of that alluminum oxide build-up when you go to change flats.
> I've been using them for over 10 years, I don't understand why more people
> don't have them.
Ceramic braking surfaces last longer but degrade, not improve,
braking performance, and they eat brake pads. Explanation in the FAQ:
http://www.faqs.org/faqs/bicycles-faq/part3/section-33.html
--
terry morse Palo Alto, CA htttp://www.terrrymorse.com/bike/
jim beam
ceramic rims are great, /definitely/ improve braking and last forever.
don't let anyone tell you different.
just because cant and witchcraft get repeated with sickening regularity
on this forum - particularly cant and witchcraft masquerading as
"technical wisdom" from people that specialize in scornfully deriding
anyone that /dares/ raise the specter of truth - has _zero_ effect on
it's accuracy.
jim beam
Chris Zacho The Wheelman
>If you go with ceramic (coated) rims,
>anything goes, pad-wise. They last 3-4
>times the life of regular alluminum
>surface rims (as long as you don't beat
>them up by running into things), brake
>better, and there none of that alluminum
>oxide build-up when you go to change
>flats. I've been using them for over 10
>years, I don't understand why more
>people don't have them. The initial outlay
>is 2-3 times as much, but they pay for
>themselves in the long run.
>-pete
Do they make a touring rim (700c, hook bead, 25+mm width, preferably in
a box channel cross section)?
May you have the wind at your back.
And a really low gear for the hills!
Chris
Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner
Chris Zacho The Wheelman
It didn't work.
If I see chips of silver in a pad, I immediately suspect it to be metal.
I check the rim carefully, with a cotton ball to see if it's scarred,
sand it lightly if necessary and chuck the pads for new ones.
One pair of Fiamme red lables was enough of a lesson for me!
Phil, Squid-in-Training
> It didn't work.
Uh... did you mean what you said?
--
Phil, Squid-in-Training
Robin Hubert
news:th%Ya.23985$K4.13...@twister.tampabay.rr.com...
> > I have ruined a set of rims by trying to clean the aluminum out of them.
> > It didn't work.
>
> Uh... did you mean what you said?
>
> --
Considering the subject line, no.
--
Robin Hubert <cv2...@earthlink.net>
Peter Cole
What happens is that little pieces of road grit get stuck in the brake pads
during wet rides. These shave off bits of aluminum, and wear out rims quickly.
You can dig them out, but it's a bother. A better solution is to use pads with
a hard enough compound that prevents grit pick up. The best working type is
KoolStop "salmon" colored pads.
Peter Cole
news:86ZYa.98$%L1...@newssvr25.news.prodigy.com..
>
> Terry Morse wrote:
> > Pete Grey wrote:
> >
> >
> >>If you go with ceramic (coated) rims, anything goes, pad-wise.
> >
> >
> > Not true at all, see the FAQ below for why.
> >
.
> bullshit.
>
> ceramic rims are great, /definitely/ improve braking and last forever.
> don't let anyone tell you different.
I have ceramic rims on one bike. They're OK, not great. I don't think they're
worth the expense & drawbacks overall.
Chris Zacho The Wheelman
Yes. I removed the pads, picked out all the chips I could find and even
sanded them to be sure there weren't any I missed.
They worked fine for a few miles and then the scraping started again.
Tried it a second time, same results. This time it was on a long
mountain tour (no bike shops).
By the time I got home my rim surfaces were hopelessly scored, even
scaled. regardless of what rubber I put on the brake arms, they would
pick up the now loosened aluminum.
Replaced the rims, used a different brand of pads (Kool Stop). No
problems. But I was out a lot of dough for two formerly perfectly good
sew-up rims.
Terry Morse
> bullshit.
>
> ceramic rims are great, /definitely/ improve braking and last forever.
> don't let anyone tell you different.
>
> just because cant and witchcraft get repeated with sickening regularity
> on this forum - particularly cant and witchcraft masquerading as
> "technical wisdom" from people that specialize in scornfully deriding
> anyone that /dares/ raise the specter of truth - has _zero_ effect on
> it's accuracy.
>
> jim beam
Well, well, Mister Top Poster. Since you have dared to raise the
"specter of truth" among the heathens, you're now on the hot seat.
Please explain where the FAQ is wrong when it comes to ceramic
braking surfaces, and be prepared to back up your argument with
technical details. This is a technical newsgroup, after.
This should be entertaining.
jim beam
anyway, the main contention of the "no ceramic" argument is that
"ceramic is an insulator". thermal insulation and electrical insulation
are not the same. indeed, if some ceramics were not able to function as
excellent thermal conductors while acting as electrical insulators, you
wouldn't be able to read this message because most of the chips in your
p.c. rely on these twin properties for their substrates.
the ceramics used in rims /are/ good thermal conductors and therefore
work very well - as people that use them can attest.
why are you so hostile? and what is the reason for assuming that a
multi-million dollar a year multi-nationals like mavic [or any of the
other non-cycling component manufacturers that use this kind of
anti-wear treatment] would bother pouring millions of dollars into r & d
and yet still somehow fail to comprehend the fundamental "thermal"
physics as assumed by the faq?
jb
Sorni
news:oiXZa.312$9Y2.25...@newssvr13.news.prodigy.com, forcing me to cut 'n
paste thusly:
> Terry Morse wrote:
> > jim beam wrote:
> >
> >
> >>bullshit.
> >>
> >>ceramic rims are great, /definitely/ improve braking and last forever.
> >>don't let anyone tell you different.
> >>
> >>just because cant and witchcraft get repeated with sickening regularity
> >>on this forum - particularly cant and witchcraft masquerading as
> >>"technical wisdom" from people that specialize in scornfully deriding
> >>anyone that /dares/ raise the specter of truth - has _zero_ effect on
> >>it's accuracy.
> >>
> >>jim beam
> >
> >
> > Well, well, Mister Top Poster. Since you have dared to raise the
> > "specter of truth" among the heathens, you're now on the hot seat.
> > Please explain where the FAQ is wrong when it comes to ceramic
> > braking surfaces, and be prepared to back up your argument with
> > technical details. This is a technical newsgroup, after.
> >
> > This should be entertaining.
> why are you so hostile?
OK, so let me get this straight: you call someone else's opinion
"bullshit". He replies, challenging you to back up your argument. Then you
ask why HE is so hostile?!?
Got it.
Bill "Crossmax XL ceramics, btw; great wheels but braking surface ain't
nothin' special" S.
jim beam
and i apologise to terry for the filthy mouth. it's not you. i just
get wound up reading an faq that is so often repeated and yet just plain
wrong.
jb
terry morse
> anyway, the main contention of the "no ceramic" argument is that
> "ceramic is an insulator". thermal insulation and electrical insulation
> are not the same. indeed, if some ceramics were not able to function as
> excellent thermal conductors while acting as electrical insulators, you
> wouldn't be able to read this message because most of the chips in your
> p.c. rely on these twin properties for their substrates.
Alumina is the ceramic material most often used on bicycle rims.
Alumina (Al2 O3) has a _thermal_ conductivity about 16% that of
aluminum, so replacing aluminum with alumina reduces the conductivity
by a factor of 6. The FAQ implies this, so I don't see where the FAQ
is clearly wrong.
> the ceramics used in rims /are/ good thermal conductors and therefore
> work very well - as people that use them can attest.
Six times worse than the material it replaces is not my idea of "very
well".
> and what is the reason for assuming that a
> multi-million dollar a year multi-nationals like mavic [or any of the
> other non-cycling component manufacturers that use this kind of
> anti-wear treatment] would bother pouring millions of dollars into r & d
> and yet still somehow fail to comprehend the fundamental "thermal"
> physics as assumed by the faq?
There are any number of "innovations" put out by Mavic and others that
show their disregard for (or ignorance of) durability and performance.
Changing from dual-sockets to single, hard anodizing, and machining
sidewalls are three such examples. The naive public without the
ability to judge these items on an engineering basis buy these
"innovations" as improvements, when in fact they are just the
opposite.
Ceramic coatings on the braking surface is another problem source. The
only valid justification for their use would be in very dirty
environments that would otherwise wear down aluminum quickly. The
trade-off for using ceramic is decreased braking performance and
quickly wearing pads.
--
terry morse Palo Alto, CA http:/www.terrymorse.com/bike/
Mike S.
> I have ceramic rims on one bike. They're OK, not great. I don't think
they're
> worth the expense & drawbacks overall.
>
normal Reflex, the rear is a SSC with 3 sets of Mavic logos. The rear
evidently doesn't have as much ceramic coating, 'cause my regular brakes
last on the rear, but the fronts are gone quickly.
The braking is good, but the rim eats pads if you aren't running the ceramic
specific pads.
I'd stay away if you're riding mtn bikes anywhere where you're likely to
taco the wheel 'cause replacing the ceramic rim is spendy. I've hit strange
things (roots, rocks, funny ruts, etc.) mtn biking and have had to rebuild
wheels several times in quick succession.
That help?
Mike
Mike
Mike S.
"Do they make a touring rim (700c, hook bead, 25+mm width, preferably in
a box channel cross section)?
I saw some NOS MA2/40 (I can't remember which) on www.renaissancecycles.com.
Now if I could just find some Campy Omega XL clinchers, I'll be happy as a
pig in mud.
That help?
Mike
jim beam
* it's not pure alumina. it contains a number of ceramic elements which
improve both wear resistance and thermal conductivity - including
titania and allegedly silicon carbide - but i can't confirm this,
unfortunately.
> Alumina (Al2 O3) has a _thermal_ conductivity about 16% that of
> aluminum
* a lot of rim alloys are 6061 or thereabouts. 6061 only has 70% of the
thermal conductivity of pure al, i.e. 167W/mK vs. 237W/mK.
* some alumina/silicon carbide ceramics have thermal conductivities in
the range of 71-200W/mK, potentially much better than 6061.
> There are any number of "innovations" put out by Mavic and others that
> show their disregard for (or ignorance of) durability and performance.
> Changing from dual-sockets to single,
* there was a time when i would have agreed with you on this, but my
experience is that it depends on the application. ma3's are very strong
& reliable - more so than open pro's in my view. making these double
eyelet would be an exercise in pointlessness.
hard anodizing,
* my experience of hard anodizing has been great. like ceramic, it's
much less prone to the effects of pad contamination and continues to
offer a highly wear resistant braking surface in all conditions. plain
al rims with contaminated pads have been far worse at stopping me in the
wet than ceramic or hard anodized.
and for the record, i've read substantial verbiage on this group to the
effect that anodizing causes fatigue. in rim applications this is
almost never the case from all the examples i've seen.
in extreme cases, cracked anodizing /can/ be a fatigue initiator, but
this is not seen often in the kind off applications we're talking about
here. all kinds of fatigue-loaded components in planes, cars,
motorcycles and bicycles are anodized for corrosion resistance very
successfully with no adverse affects. one notable example has to be
suspension forks. both bicycle and motorcycle forks use [hard] anodized
stantions for improved friction properties, corrosion and wear
resistance, and i've yet to see fatigue resulting from the anodizing
alone - it's always been initiated by stone strike damage or some other
flaw.
unforunately, the cracking most commonly attributed to
anodizing-initiated fatigue in bicycle rims - pure circumferential
cracking - is actually due to extrusion weaknesses in the alloy's
microstucture. if anyone wants to drag a certain french rim
manufacturer over red hot coals for poor q.c. in this department, be my
guest, but don't blame it on the anodizing.
and machining
> sidewalls
* this is one that requires a real double-take when reading the faq!
machines sidewalls offer several benefits:
1. there is no "bed in" period for the pads - they fit right out of the
box and provide full braking power. i really notice the difference
braking an unmachined rim on new pads vs. a machined rim & new pads.
2. there is no potential for wheels locking at any bumps at the joint.
i know some people swear this is never an issue, but i can personally
attest to owning a mavic cxp14 unmachined rim showing a marked
propensity to locking when under full braking - there is a bald patch on
my tire where the lock sets in at the same place every time.
3. rims are _not_ "machined with ridges to prevent squeal" or merely for
appearance. 6061 is not very friendly to normal lathe operations [the
surface has a tendency to gouge and rip when the machining off-cut fouls
the tool]. the ridges on the machined surface are merely the result of
using a slightly convex diamond cutting tool which offers the best
[read: cheapest, fastest, cleanest] machining results for this
application in a single pass.
Terry Morse
> > There are any number of "innovations" put out by Mavic and others that
> > show their disregard for (or ignorance of) durability and performance.
> > Changing from dual-sockets to single,
>
> * there was a time when i would have agreed with you on this, but my
> experience is that it depends on the application. ma3's are very strong
> & reliable - more so than open pro's in my view. making these double
> eyelet would be an exercise in pointlessness.
It depends on your definition of "durability":
The MA3 rim, with its machined sidewalls, single eyelets, and
anodized surface is no match for the now gone MA2, which had
unmachined sidewalls, double eyelets, and a polished surface. Why
did Mavic replace a rim that lasted so long with one that's
inferior, one may ask rhetorically.
--
terry morse Palo Alto, CA http://www.terrymorse.com/bike/
Terry Morse
> and for the record, i've read substantial verbiage on this group to the
> effect that anodizing causes fatigue. in rim applications this is
> almost never the case from all the examples i've seen.
>
> in extreme cases, cracked anodizing /can/ be a fatigue initiator, but
> this is not seen often in the kind off applications we're talking about
> here. all kinds of fatigue-loaded components in planes, cars,
> motorcycles and bicycles are anodized for corrosion resistance very
> successfully with no adverse affects. one notable example has to be
> suspension forks. both bicycle and motorcycle forks use [hard] anodized
> stantions for improved friction properties, corrosion and wear
> resistance, and i've yet to see fatigue resulting from the anodizing
> alone - it's always been initiated by stone strike damage or some other
> flaw.
Hard (Type III sulfuric acid 0.0023") anodizing reduces the fatigue
life of Al alloys by about 60%. You can find references to this
number in the literature. Hard anodizing is only appropriate for
thick, lowly stressed members. Rims don't qualify for hard anodizing
on either count.
--
terry morse Palo Alto, CA http://www.terrymorse.com/bike/
jobst....@stanfordalumni.org
>> And for the record, I've read substantial verbiage on this group to
>> the effect that anodizing causes fatigue. In rim applications this
>> is almost never the case from all the examples I've seen.
It's good you add "from all the examples I've seen" because materials
literature is full of description of such failures. Back in the days
of the MA-2 I sent a well used MA-2 and a G-40 to the metallurgical
lab at ALCAN to a bikie and tribologist who ran them through
micro-inspection of cut and polished cross sections. As expected, the
MA-2 had no cracks while the G-40 had a crazed surface and several
large cracks that were initiated by its brittle hardcoat.
>> In extreme cases, cracked anodizing /can/ be a fatigue initiator,
>> but this is not seen often in the kind off applications we're
>> talking about here.
What do you call "extreme cases", in the early days of anodizing at
Mavic we had daily reports of cracked rims here on wreck.bike. Fresh
out of the crate these MA-40 rims displayed crazed surfaces when
illuminated by bright grazing incidence light. I suspect that is
because the extrusions were anodized before forming hoops.
>> All kinds of fatigue-loaded components in planes, cars, motorcycles
>> and bicycles are anodized for corrosion resistance very
>> successfully with no adverse affects. One notable example has to
>> be suspension forks. Both bicycle and motorcycle forks use [hard]
>> anodized stanchions for improved friction properties, corrosion and
>> wear resistance, and I've yet to see fatigue resulting from the
>> anodizing alone - it's always been initiated by stone strike damage
>> or some other flaw.
You picked the wrong application. These elements are built for
rigidity and do not sustain high stress. Rims flex continually in use
and sustain high bending stresses, ones that effect the "outer fibers"
from the axis of bend greatest. On top of that there are stress
concentrations and residual stress in the rim around spoke holes. It
is the aircraft industry that has the most to say about the hazards of
anodizing that acts as a natural crack initiator and must be avoided
for any high stress applications.
What makes you such a defender of poor engineering and manufacture?
What do you get out of this?
> Hard (Type III sulfuric acid 0.0023") anodizing reduces the fatigue
> life of Al alloys by about 60%. You can find references to this
> number in the literature. Hard anodizing is only appropriate for
> thick, lowly stressed members. Rims don't qualify for hard anodizing
> on either count.
> terry morse
I'm glad to see that others can see past the false promotional claims
of such manufacturers. Unfortunately many people identify with their
purchase so completely that finding fault with it becomes equivalent
to self criticism... I am my bicycle, my bicycle is me. I was smart
enough to buy it. It must be good.
Jobst Brandt
jobst....@stanfordalumni.org
Palo Alto CA
Terry Morse
> Terry Morse writes:
>
> >> And for the record, I've read substantial verbiage on this group to
> >> the effect that anodizing causes fatigue. In rim applications this
> >> is almost never the case from all the examples I've seen.
For the record, I didn't write the above section, which I disagree
with. That was written by Jim Beam.
jim beam
> literature is full of description of such failures. Back in the days
> of the MA-2 I sent a well used MA-2 and a G-40 to the metallurgical
> lab at ALCAN to a bikie and tribologist who ran them through
> micro-inspection of cut and polished cross sections. As expected, the
> MA-2 had no cracks while the G-40 had a crazed surface and several
> large cracks that were initiated by its brittle hardcoat.
jobst, mavic don't make the ma40 any more. isn't it time you also moved on?
1. last time you talked about your "alcan" friend you said it was dye
penetrant testing. that would not reveal extrusion flaws in the
microstructure. it's a little disturbing to see you subtly massage your
story to suit your argument. are you going to post the pics so we can
all see what you really did?
2. ma2 was also available in anodized. i have one to prove it. you
never differentiate between ma2 "bright" and ma2 silver anodized.
presumably neither cracked for you.
3. a fork is a low-stress application??? you care to step outside and
debate that some time big boy? i've never heard such a crock.
jobst....@stanfordalumni.org
>> It's good you add "from all the examples I've seen" because
>> materials literature is full of description of such failures. Back
>> in the days of the MA-2 I sent a well used MA-2 and a G-40 to the
>> metallurgical lab at ALCAN to a bikie and tribologist who ran them
>> through micro-inspection of cut and polished cross sections. As
>> expected, the MA-2 had no cracks while the G-40 had a crazed
>> surface and several large cracks that were initiated by its brittle
>> hardcoat.
> Jobst, Mavic don't make the ma40 any more. isn't it time you also moved on?
So what! The point is that identical extrusions, (and I don't recall
whether it was a G-40 or MA-40) one polished, the other anodized
demonstrated the effect described in metallurgical journals about
anodizing, a brittle surface coating developed in/on the parent metal.
> 1. Last time you talked about your "ALCAN" friend you said it was
> dye penetrant testing. That would not reveal extrusion flaws in the
> microstructure. It's a little disturbing to see you subtly massage
> your story to suit your argument.
Yes? So what is not to your liking? Dye makes cracks visible in the
cut and polished cross sections. What "disturbs" you about that?
Besides, this is all old hat.
> Are you going to post the pics so we can all see what you really
> did?
I filed those away and would have to search for their location.
That's pretty old stuff.
> 2. MA-2 was also available in anodized. I have one to prove it.
> you never differentiate between Ma-2 "bright" and MA-2 silver
> anodized. Presumably neither cracked for you.
The anodized version was called an MA-40 or G-40. I have never seen a
black MA-2.
> 3. A fork is a low-stress application??? You care to step outside and
> debate that some time big boy? I've never heard such a crock.
That is so because a fork failure usually leads to serious injury. If
ridden in rain, rims wear out before developing fatigue cracks and
only since rims were anodized did a large number of rims have sections
pull out at individual spokes. Some rims without double wall sockets
even cracked circumferentially so that the tire remained mounted on
the outer part that was no linger connected to the bed.
Chris Zacho The Wheelman
>I saw some NOS MA2/40 (I can't
>remember which) on
>www.renaissancecycles.com.
>Now if I could just find some Campy
>Omega XL clinchers, I'll be happy as a pig in
>mud.
>That help?
>Mike
The link led to a company selling panniers for MTB's. Not exactly what I
was looking for, but thanks for trying...
Mike S.
"Chris Zacho "The Wheelman"" <Chrisz...@webtv.net> wrote in message
news:14074-3F...@storefull-2353.public.lawson.webtv.net...
mikeshaw2@coxDOTnet (Mike S.) Wrote:
>I saw some NOS MA2/40 (I can't
>remember which) on
>www.renaissancecycles.com.
>Now if I could just find some Campy
>Omega XL clinchers, I'll be happy as a pig in
>mud.
>That help?
>Mike
The link led to a company selling panniers for MTB's. Not exactly what I
was looking for, but thanks for trying...
May you have the wind at your back.
And a really low gear for the hills!
Chris
Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner
Try this: http://www.renaissance-cycles.com/
Just copied it from my favorites, so I know it works.
Mike
jim beam
what does a similar cross-section have to do with alloy composition or
heat treatment? the difference between ma40 and ma2 is more than just
the color of the anodizing.
> Yes? So what is not to your liking? Dye makes cracks visible in the
> cut and polished cross sections. What "disturbs" you about that?
what disturbs me is that you consistently fail to observe a complete
failure analysis methodology, yet you feel qualified to "talk with
authority" on a subject into which you've only dipped one toe. you
didn't do the metallography. microstructure has a key influence on
crack propagation & growth. you /have/ to do it if you want to get to
the bottom of a failure, not stop at some point which happens to support
the thesis you want to promote.
> I filed those away and would have to search for their location.
> That's pretty old stuff.
how convenient.
> I have never seen a black MA-2.
no. but i'll bet you've used a silver anodized one though!
if you want to convince me you know what you're talking about, answer
these questions:
1. what is a dislocation?
2. what is the relationship between slip planes and fatigue nucleation?
3. in terms of dislocations, how do materials that exhibit fatigue
endurance limits differ from those that don't?
and if you'd care to put this in the context of your spoke "stress
relief" theory, that would be just great.