Mavic MA-40 - Piece of Crap? - Page 8

Carl Fogel writes:

> You might become fascinating by trying to put a number on how rapidly the MA-40 rims failed.
> Elsewhere in this thread, Jim Beam suggested that rims wear out from braking in only 25,000
> miles, but that the accelerated fatigue of anodizing-induced cracking might become a problem in
> 40,000 miles.

Let's put it this way, many of the failed rims, specifically MA-40's had not yet had their braking
surface worn through to the metal when they failed. I never rode on these, being aware of their
drawbacks. I had the opportunity to use someone else's MA-40 when he complained of bad braking,
which I verified before we switched front wheels back to our own. That was my only experience.

> Or you might name the manufacturer and explain what part of which process you think that they
> don't understand (anodizing, machining, fatigue, or whatever) rather than leaving us to guess.

If you attend the InterBike trade show and talk to some of the manufacturers, it becomes evident
that some of these processes are stabs in the dark for market share, with no sensible explanation
for doing so. Take mixed color treads on tires. If you ask why the answers are contradictory since
you need the best traction you can get for braking straight ahead as well as while cornering, yet
they one manufacturer claims the green tread in the center is for braking and the black on the sides
for cornering while the next one will give the same explanation for the reverse pattern.

None of them will tell how they came upon their crank attachment scheme or for that matter it's
advantages since they can't explain away their previous design that was claimed to do the same
things best. For instance, the reason for the previous Shimano crank (spline) attachment failures
with people who stand, right foot forward, was not understood. To Shimano it seemed to be a random
occurrence. You read what causes it here, if you recall.

If you ask about anodizing, you get the same "harder, stronger, better wear," etc talk you can get
here, in spite of early rim failures that were unknown prior to anodizing. This is akin to asking a
bicyclist who shaves his legs, why. The answers dodge that it is for the same reason women or body
builders shave... vanity, but practitioners don't want to admit it, just as the anodizing folks
don't. Its like the black SUV with black windows. It's the IN thing.

Jobst Brandt jobst.brandt@stanfordalumni.org

Carl Fogel writes:

> You might become fascinating by trying to put a number on how rapidly the MA-40 rims failed.
> Elsewhere in this thread, Jim Beam suggested that rims wear out from braking in only 25,000
> miles, but that the accelerated fatigue of anodizing-induced cracking might become a problem in
> 40,000 miles.

Let's put it this way, many of the failed rims, specifically MA-40's had not yet had their braking
surface worn through to the metal when they failed. I never rode on these, being aware of their
drawbacks. I had the opportunity to use someone else's MA-40 when he complained of bad braking,
which I verified before we switched front wheels back to our own. That was my only experience.

> Or you might name the manufacturer and explain what part of which process you think that they
> don't understand (anodizing, machining, fatigue, or whatever) rather than leaving us to guess.

If you attend the InterBike trade show and talk to some of the manufacturers, it becomes evident
that some of these processes are stabs in the dark for market share, with no sensible explanation
for doing so. Take mixed color treads on tires. If you ask why the answers are contradictory since
you need the best traction you can get for braking straight ahead as well as while cornering, yet
they one manufacturer claims the green tread in the center is for braking and the black on the sides
for cornering while the next one will give the same explanation for the reverse pattern.

None of them will tell how they came upon their crank attachment scheme or for that matter it's
advantages since they cant explain away their previous design that was claimed to do the same things
best. For instance, the reason for the previous Shimano crank (spline) attachment failures with
people who stand, right foot forward, was not understood although it seemed to be a random
occurrence. You read its cause here if you recall.

If you ask about anodizing, you get the same "harder, stronger, better wear," etc talk you can get
here, in spite of early rim failures that were unknown prior to anodizing. This is akin to asking a
bicyclist who shaves his legs, why. The answers dodge that it is for the same reason women or body
builders shave... vanity, but practitioners don't want to admit it, just as the anodizing folks
don't. Its like the black SUV and black windows. It's the IN thing.

Jobst Brandt jobst.brandt@stanfordalumni.org

That is an understatement.

jobst.brandt@stanfordalumni.org wrote:
> Carl Fogel writes:
>
>
>>You might become fascinating by trying to put a number on how rapidly the MA-40 rims failed.
>>Elsewhere in this thread, Jim Beam suggested that rims wear out from braking in only 25,000
>>miles, but that the accelerated fatigue of anodizing-induced cracking might become a problem in
>>40,000 miles.
>
>
> Let's put it this way, many of the failed rims, specifically MA-40's had not yet had their braking
> surface worn through to the metal when they failed. I never rode on these, being aware of their
> drawbacks. I had the opportunity to use someone else's MA-40 when he complained of bad braking,
> which I verified before we switched front wheels back to our own. That was my only experience.

so that extensive scientific research qualifies you to condemn and bully? unimpressive. and you have
the temerity to complain that the rim manufacturing industry ignores you?

>
>
>>Or you might name the manufacturer and explain what part of which process you think that they
>>don't understand (anodizing, machining, fatigue, or whatever) rather than leaving us to guess.
>
>
> If you attend the InterBike trade show and talk to some of the manufacturers, it becomes evident
> that some of these processes are stabs in the dark for market share, with no sensible explanation
> for doing so. Take mixed color treads on tires. If you ask why the answers are contradictory since
> you need the best traction you can get for braking straight ahead as well as while cornering, yet
> they one manufacturer claims the green tread in the center is for braking and the black on the
> sides for cornering while the next one will give the same explanation for the reverse pattern.

ah, yes, trade shows. where companies leave their sales droids at home and ship their best
researchers out for your entertainment.

color is irrelevant. durometer/traction ratings however are /highly/ relevant. as usual, you use the
fact that color makes no difference to "support" a baseless supposition that mechanical properties
are similarly ignorable.

>
> None of them will tell how they came upon their crank attachment scheme or for that matter it's
> advantages since they can't explain away their previous design that was claimed to do the same
> things best. For instance, the reason for the previous Shimano crank (spline) attachment failures
> with people who stand, right foot forward, was not understood. To Shimano it seemed to be a random
> occurrence. You read what causes it here, if you recall.

missed that one. should be entertaining.

>
> If you ask about anodizing, you get the same "harder, stronger, better wear," etc talk you can get
> here, in spite of early rim failures that were unknown prior to anodizing.

apples with apples. those were different alloys. but let's talk about current technology and current
rim failures. how many open pro cd rims have you seen crack? what proportion have been subject to
formal failure analysis? what proportion are directly attributable to anodizing? and how does that
correlate to the failure rate of the black anodized and silver anodized open pro versions? show us
some figures.

> This is akin to asking a bicyclist who shaves his legs, why. The answers dodge that it is for the
> same reason women or body builders shave... vanity, but practitioners don't want to admit it,
> just as the anodizing folks don't. Its like the black SUV with black windows. It's the IN thing.

yet another irrelevant red herring.

>
> Jobst Brandt jobst.brandt@stanfordalumni.org

Carl Fogel wrote:
> jim beam <uce@ftc.gov> wrote in message news:<4ynHb.2647$ay.2210@newssvr27.news.prodigy.com>...
>
>>Carl Fogel wrote:
>>
>>>I suppose that someone must have mentioned the anti-wear protection of anodizing,
>>
>>not that i've seen on this forum. all i see is a bunch of red herrings confusing anodizing with
>>ceramic coating, an entirely different process involving plasma spray, not electrolysis.
>
>
> Dear Jim,
>
> Perhaps I misunderstood, but I thought that Jobst indicated elsewhere in this thread that the thin
> layer of anodized aluminum functions as an insulator, either as a ceramic or like a ceramic.

swallowed a red herring.

yes, aluminum oxide is technically a ceramic, but it is not /the/ ceramic used in the rim coating
sense. also, aluminum oxides are not necessarily bad thermal conductors. nor are 6061 aluminum
alloys good thermal conductors.

>
> I hadn't thought of pretty metal as being the same as a beer mug, but if the metal adds molecules
> and sort of fluffs up (see why I ask the questions around here instead of trying to answer them?),
> then it seemed plausible that it would act as an insulator, making for hotter and less efficient
> brake pads.

not necessarily relevant. there is extensive research on ceramics being used in high performance
brake systems, both disks & pads.

http://www.uni-stuttgart.de/IFKB/en/research/17-e.pdf shows disks.

>
> I take it that ceramic coating by plasma spray is an entirely different process.

entirely different.

scroll to the bottom of this page for a schematic

http://www.gordonengland.co.uk/tsc.htm

> Does it suffer from the same insulation problem?

depends on the ceramic. to be fair, mavic /do/ list thermal insulation as one of their reasons for
use, but as you will see from a little research, alumina & titania can be excellent thermal
conductors.

> Of course, I'm lost again. Going through this thread, I can't even tell which kind of rims
> (anodized or plain) stop better when dry, much less what happens when wet--something that I
> thought would be fairly cut-and-dried.

the proof of the pudding is in the eating. my experience of ceramic & cd rims is entirely favorable
- and no comparision to a badly fouled pad full of metal scrapings.

>
> But I still think that the subject is fascinating,

fascinating indeed! that's why i got into materials.

> just as I think the nature of the responses is fascinating. I do appreciate how you and Jobst are
> taking the time to grapple with these things. And I'm still startled by how something as simple as
> a metal hoop can be so tricky.
>
> Thanks again,
>
> Carl Fogel

BaCardi <usenet-forum@cyclingforums.com> writes:

> Tim McNamara wrote:
> > BaCardi <usenet-forum@cyclingforums.com> writes:
>
> > >> Read page 2. Then come back and talk to me.
>
> > Ah, that explains it. BaCardi is Paul Harvey on a bender.
>
> No son.

You're not my father.

> Try again.

Why?

> You've got nothing on Paul Harvey. Come back after you've done some legitimate research.

Apparently you should learn to read.

"SMMB" <sandibek@mail.russia> writes:

> Hear, hear !! An honest and competent expert shines by offering fact-based opinions, not personal
> anecdotes, and just as much by honoring the limitations of his own expertise. Nasty words, hostile
> repostes, and self-indulgent vanity don't make any sort of expert.

Hmm. And yet, espousing this, you saw fit to applaud "jim beam" who commits all these things
regularly?

"David L. Johnson" <david.johnson@lehigh.edu> writes:

> On Fri, 26 Dec 2003 10:28:35 +0000, Carl Fogel wrote:
>
> > Which kind of rims provide better caliper braking, constant or varying width? How much better?
> > That is, at what point does varying rim width become noticeable when braking?
> >
> You're not asking the right question. You assume that the machining of the rim is done to make the
> width more uniform. You also assume that the machining makes a uniform rim. But machined sidewalls
> only came about after rims were anodized. If a non-machined rim was so uneven, it would have been
> a very good idea to machine it smooth even before they were anodized.
>
> The rims are machined to scrape off the anodized surface from the braking flats, since anodizing
> on the flats ruins the braking performance.

Basically machining compensates for several problems caused or worsened by anodizing: poor wet
braking performance, brake squeal, rapid brake pad wear, and ugliness when the anodizing starts to
be worn off by the brakes. You'll also see an interesting pattern of wear, which is shiny patches of
almost completely bare aluminum coinciding with the spokes, and patches of partial wear coinciding
with the spaces bewtwwen the spokes. Machining removes all these problems by removing the anodizing
from the braking surface.

Wheel builders like machined sidewalls because it makes wheels look "truer" on a truing stand when
showing off to the customer: "true to within .001 inches" even though the wheel is really not any
truer than it would been with non-machined rims. It's just had the high spots of the extrusion
flattened down.

BaCardi <usenet-forum@cyclingforums.com> writes:

> Jay Beattie wrote:
>
> > Welding and machining a seam may be a good thing, and IIRC, Weinmann was doing that 30 years
> > ago on the Concaves. But machining and anodizing the whole rim is entirely unnecessary and
> > arguably bad for the rim. Even in the dark days, a bad seam could be fixed with about one
> > minute of filing. And the rims only cost $10 or $15 a pop -- and not $60. -- Jay Beattie.
>
> Better to buy the rim already machined, then to take a file to file down an uneven seam.

No, it's not.

<jobst.brandt@stanfordalumni.org> wrote:

> If you attend the InterBike trade show and talk to some of the manufacturers, it becomes evident
> that some of these processes are stabs in the dark for market share, with no sensible explanation
> for doing so.

Well that's your first mistake. The staff that companies send to trade shows are almost never the
ones to ask technical questions. Instead you get the marketing droids and the salespeople who don't
know ****. The folks who really do understand the processes are kept far away from the shows because
they don't always speak the company line. To say that "manufacturer doesn't understand the process
being used and why" is more revealing about you than the company.

You also have an annoying tendency to lump all anodization processes together, which is about the
same as saying all aluminum alloys are equal.

Yes, it is.

BaCardi wrote:
> Better to buy the rim already machined, then to take a file to file down an uneven seam.

That's your take on it. My take is, save me $40 per rim and hand me the file for 3-5 minutes work.

Mark (I buy the silver rims when I can find 'em cheap) Janeba

BaCardi <usenet-forum@cyclingforums.com> wrote in message news:<hHFHb.8765$Pa1.5330@fe14.private.usenetserver.com>...
> Carl Fogel wrote:
> > Carl Fogel writes: Dear Jobst, No, but you're awfully close to being pompous. Carl Fogel
>
> That is an understatement.

Dear Bacardi,

Pol. "My lord, I will use them according to their desert.

Ham. "God's bodkin, man, much better; use every man after his desert, and who shall scape
whipping? Use them after your own honor and dignity--the less they deserve, the more merit is in
your bounty."

Let us be cautious when tempted by our ill-nature. It so often comes flying back in our faces.

Pompously,

Carl Fogel

Jim Beam writes:

>>> You might become fascinating by trying to put a number on how rapidly the MA-40 rims failed.
>>> Elsewhere in this thread, Jim Beam suggested that rims wear out from braking in only 25,000
>>> miles, but that the accelerated fatigue of anodizing-induced cracking might become a problem in
>>> 40,000 miles.

>> Let's put it this way, many of the failed rims, specifically MA-40's had not yet had their
>> braking surface worn through to the metal when they failed. I never rode on these, being aware of
>> their drawbacks. I had the opportunity to use someone else's MA-40 when he complained of bad
>> braking, which I verified before we switched front wheels back to our own. That was my only
>> experience.

> So that extensive scientific research qualifies you to condemn and bully? Unimpressive. And you
> have the temerity to complain that the rim manufacturing industry ignores you?

Who said that rim manufacturers ignore me? I don't see that anywhere. You might notice that few if
any people in the industry read wreck.bike and I don't expect them to although they might get a
sense of what ails the customer and what sort of rumors are being spread.

My experience comes mainly from failures I have seen at the local bicycle shops, Palo Alto Bicycles
and formerly Wheelsmith and occasionally others, not to mention the rash of reports that we have
seen here. You may have missed that I took the trouble to section an MA-2 and MA-40 and have the
materials lab polish a cross section to reveal crack initiation. This was a few years back before
rims got heavier and deeper cross sections just so we could ride colored rims.

>>> Or you might name the manufacturer and explain what part of which process you think that they
>>> don't understand (anodizing, machining, fatigue, or whatever) rather than leaving us to guess.

>> If you attend the InterBike trade show and talk to some of the manufacturers, it becomes evident
>> that some of these processes are stabs in the dark for market share, with no sensible explanation
>> for doing so. Take mixed color treads on tires. If you ask why the answers are contradictory
>> since you need the best traction you can get for braking straight ahead as well as while
>> cornering, yet they one manufacturer claims the green tread in the center is for braking and the
>> black on the sides for cornering while the next one will give the same explanation for the
>> reverse pattern.

> Ah, yes, trade shows. Where companies leave their sales droids at home and ship their best
> researchers out for your entertainment.

Many of these booths are manned by the principals and owners of the businesses. I don't think it's
fair to rake the whole bunch over the idiot coals, just because there are some nut cases on
display there.

> Color is irrelevant. Durometer/traction ratings however are /highly/ relevant. As usual, you use
> the fact that color makes no difference to "support" a baseless supposition that mechanical
> properties are similarly ignorable.

You choose to ignore that colored rubber does not use carbon as part of the mix, and that until now
the colored treads have poorer traction and durability than carbon compounded tread rubber. Hence
colored tread is more a fashion statement than a functional choice, similar to colored rims.

>> None of them will tell how they came upon their crank attachment scheme or for that matter it's
>> advantages since they can't explain away their previous design that was claimed to do the same
>> things best. For instance, the reason for the previous Shimano crank (spline) attachment failures
>> with people who stand, right foot forward, was not understood. To Shimano it seemed to be a
>> random occurrence. You read what causes it here, if you recall.

> Missed that one. Should be entertaining.

>> If you ask about anodizing, you get the same "harder, stronger, better wear," etc talk you can
>> get here, in spite of early rim failures that were unknown prior to anodizing.

> Apples with apples. Those were different alloys. But let's talk about current technology and
> current rim failures. How many open pro CD rims have you seen crack? What proportion have been
> subject to formal failure analysis? What proportion are directly attributable to anodizing? And
> how does that correlate to the failure rate of the black anodized and silver anodized open pro
> versions? Show us some figures.

Does that explain what caused failures in previously durable rims when they were anodized? I don't
see the connection. If I have a failure prone material combination, I can design around it by
increasing rim weight and altering the cross section. Deeper rims have less bridging stresses across
the rim so they have less likelihood of cracks in spite of anodizing.

>> This is akin to asking a bicyclist who shaves his legs, why. The answers dodge that it is for
>> the same reason women or body builders shave... vanity, but practitioners don't want to admit
>> it, just as the anodizing folks don't. Its like the black SUV with black windows. It's the IN
>> thing.

> Yet another irrelevant red herring.

Looks is where its at these days. Maybe we are getting used to so much posturing that it doesn't
raise an eyebrow.

Jobst Brandt jobst.brandt@stanfordalumni.org

Tim McNamara <timmcn@bitstream.net> wrote in message news:<m2fzf47aar.fsf@Stella-Blue.local>...

[snip Carl Fogel and David Johnson and get to the weird wear]

> Basically machining compensates for several problems caused or worsened by anodizing: poor wet
> braking performance, brake squeal, rapid brake pad wear, and ugliness when the anodizing starts to
> be worn off by the brakes. You'll also see an interesting pattern of wear, which is shiny patches
> of almost completely bare aluminum coinciding with the spokes, and patches of partial wear
> coinciding with the spaces bewtwwen the spokes. Machining removes all these problems by removing
> the anodizing from the braking surface.
>
> Wheel builders like machined sidewalls because it makes wheels look "truer" on a truing stand when
> showing off to the customer: "true to within .001 inches" even though the wheel is really not any
> truer than it would been with non-machined rims. It's just had the high spots of the extrusion
> flattened down.

Dear Tim,

Forgive me for skipping your other points, but one of them is hogging all my attention.

You're saying that anodized wheel rims eventually show worn-off patches on the braking surface next
to the spokes?

Maybe you guys know about all this, but I'm flabbergasted.

What causes this? Are the worn patches on each side of the rim and next to each spoke, 32 on the
left and 32 on the right? Or are they staggered, 16 on one side and 16 on the other, reflecting
where the spokes pull to one side and then to the other?

Do non-anodized rims wear in the same fashion, but fail to show it to the naked eye because it's all
the same color and finish?

If the wheels wear regularly deeper next to the spokes (either staggered or symetrically), how the
hell do people true worn wheels? Is this wear, fascinating as I find it, actually inconsequential in
terms of depth?

For a simple hoop, the bicycle rim is certainly giving me my money's worth in surprises.

Thanks,

Carl Fogel