Mavic MA-40 - Piece of Crap? - Page 2

BaCardi wrote:
> Jobst Brandt wrote:
> > Oh? If all that welding, machining and heat treatment isn't a huge waste. Suckers!!! Jobst
> > Brandt jobst.brandt@stanfordalumni.org
>
>
>
> Oh and the seam welding and machining is a waste too? Give me a break
>> rolleyes:

That's it -- next time I have a bike question, forget Sheldon and Jobst and shop owners and
mechanics; just ask BaCardi!

Bill "rum a dum-dum" S.

anonymous writes:

>> Oh? If all that welding, machining and heat treatment isn't a huge waste. Suckers!!!

> Oh and the seam welding and machining is a waste too? Give me a break

And what problem did these expensive adjuncts solve? You probably did not ride on rims that were not
welded for any reasonable sampling. MA-2 rims and their equals for tubulars were used for about 50
years with no problem. Besides, the alloys used are not heat treatable. We went through that a few
years back. Why would you want to heat treat aluminum rims? I think you'll believe anything
manufacturers put out as a marketing gimmick. People actually believed Rolf's claim that his wheels,
having laterally paired spokes, prevented shimmy.

Jobst Brandt jobst.brandt@stanfordalumni.org

Tim McNamara <timmcn@bitstream.net> wrote:

> Avoid anodized rims. Well, good luck, there aren't any non-anodized rims on the (after)market to
> my knowledge except possibly the Torelli Master, and reports conflict on that rim.

Sun rims are, to the best of my knowledge, nearly all available in polished bare aluminum, most with
eyelets too.

Chalo Colina

Jim Beam writes:

> Getting back to the ma40, all modern rims are made from extruded aluminum. Extruded aluminum,
> depending on subsequent heat treatments, will usually have a strongly anisotropic microstructure.
> [Just like striped toothpaste coming out of a tube.] Modern alloys are extruded much closer to
> their ductility limits than some of the older ones. It's part of what makes them strong. If one
> sees cracking following the extruded microstructure of a component, one /has/ to assume this
> microstructure plays a significant role in failure. I believe the ma40 was a somewhat unsuccessful
> attempt to push Mavic's then-used alloy to its limits but it's failure paved the way for the
> "open" rim series with a much superior alloy. The "open" series and their successors have not been
> as failure prone, regardless of anodizing.

I have a store of MA-2 rims and they are not anodized. They are polished aluminum with a clear
lacquer finish that just barely presents an insulating I. surface rim displays electrical continuity
with a flashlight battery on its bead edge.

> I'm not sure if it's still up, but there was a very illustrative photo that showed the effect of
> microstructure on rim failure:

> in ASCII: The more common failure:
_______________ crack
> ______ ______ / \ / \ / \ / \ ___| | ____| |____ crack
> | | | |
> \ / \ /
> \______/---- \______/
_______________ crack

> Lousy drawing, but this is supposed to show the photo with the two cracks initiating at the
> eyelet. This is important because if you look at an anodized rim with a magnifier, [silver 517
> being a classic example], you will see cracks in the anodizing *radiating* around the eyelet where
> it has been punched through the rim. Straight out of the factory. Again, the anodizing cracks
> exactly radiate around the spoke hole.

You'll find that these cracks are aligned with extrusion marks and the cracks of interest are those
across bridging stresses from edge to edge of the rim, there being significantly less bending stress
between spokes. That riveting eyelets and sockets causes crazing is not unusual, however, the cracks
of interest are those that lie across principal bending planes. These are the ones that propagate
into the metal. Non anodized rims having no crust do not develop cracks as readily although cracking
is possible with cyclic overload. Steady stress great enough to cause cracks would cause immediate
failure similarly to spoke failure.

> If anodizing were to be the sole cause of cracking, one would therefore expect to see the cracking
> exactly axial with the lines of the cracked anodizing, as we see for the crack on the left. And
> there would be no variation is this failure mode.

Not so. Those cracks are not in line with the principal stress, however, there have been star burst
failures on rims with sufficiently thick anodizing.

> But on the right, this photo also showed cracking *tangential* to the spoke eyelet - i.e. /not/
> following the radial cracks in the anodizing but following inherent flaws in the metal's extruded
> microstructure.

These all ran along the direction of extrusion, finally breaking across the rim the slender bridge
they made of the mid section of the rim. This is one of the inherent disadvantages of extrusions.

> One *cannot* therefore solely attribute cracking simply to anodizing, whether it be hard, silver,
> black or purple. There don't seem to be any real micrographs on the net showing what extruded
> material looks like, but this is a good representation:

http://www.stud.ntnu.no/~fjeldly/forming.html

> Just like a piece of wood is easy to split along its grain, so can be a faulty extrusion.

Or for that matter a good extrusion.

> The ma40 was junk. Just throw it away. No, most modern rims do not have this problem.

Oh BS! A modern rim with anodizing presents the same failure. The difference is that manufacturers
are cutting back on anodizing thickness.

Jobst Brandt jobst.brandt@stanfordalumni.org

chumpychump@hotmail.com (Chalo) writes:

> Tim McNamara <timmcn@bitstream.net> wrote:
>
> > Avoid anodized rims. Well, good luck, there aren't any non-anodized rims on the (after)market to
> > my knowledge except possibly the Torelli Master, and reports conflict on that rim.
>
> Sun rims are, to the best of my knowledge, nearly all available in polished bare aluminum, most
> with eyelets too.

Huh, cool. The only current polished Al Sun rims I have seen are the
CR18. Their Web site doesn't make much of a point of showing polished rims, only the anodized ones.
Oops, I take that back, the ME14a apparently comes in polished form even though they can't be
bothered to show it:

http://www.sun-ringle.com/ShowRoom/ROAD/Rims/me14a.html

Several other rims are in the same boat. There's no discussion as to the type of eyelets- whether a
single ferrule or a socket style. Oddly enough, the CR18 is listed only as coming in a polished
finish, but in the photo it is finished in black:

http://www.sun-ringle.com/ShowRoom/R.../cr18road.html

On Tue, 23 Dec 2003 22:11:10 GMT, jobst.brandt@stanfordalumni.org
said:

>...A modern rim with anodizing presents the same failure. The difference is that manufacturers are
>cutting back on anodizing thickness.

Or perhaps, having learned that there is a problem, they are at last attempting to engineer for an
acceptable result with anodizing? This still begs the question of why to bother with anodization in
this application at all, of course.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
Words processed in a facility that contains nuts.

HAHAH! Whatever dude! The seam is machined for better braking. Now, you'll NEVER get rims that stick at the seam. But according to you its all marketing. Geez! Get a clue!

> Jobst Brandt wrote:
> > Oh? If all that welding, machining and heat treatment isn't a huge waste. Suckers!!! Jobst
> > Brandt jobst.brandt@stanfordalumni.org

BaCardi without taking the time to think first, wrote:
> Oh and the seam welding and machining is a waste too? Give me a break

Well, if it isn't wasteful why do they cost more, weigh more and last not as long?

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

jobst.brandt@stanfordalumni.org wrote:
> Jim Beam writes:
>
>
>>Getting back to the ma40, all modern rims are made from extruded aluminum. Extruded aluminum,
>>depending on subsequent heat treatments, will usually have a strongly anisotropic microstructure.
>>[Just like striped toothpaste coming out of a tube.] Modern alloys are extruded much closer to
>>their ductility limits than some of the older ones. It's part of what makes them strong. If one
>>sees cracking following the extruded microstructure of a component, one /has/ to assume this
>>microstructure plays a significant role in failure. I believe the ma40 was a somewhat unsuccessful
>>attempt to push Mavic's then-used alloy to its limits but it's failure paved the way for the
>>"open" rim series with a much superior alloy. The "open" series and their successors have not been
>>as failure prone, regardless of anodizing.
>
>
> I have a store of MA-2 rims and they are not anodized. They are polished aluminum with a clear
> lacquer finish that just barely presents an insulating I.

/is/ it laquer? are you able to remove with the correct solvent? as i said, mavic sold these
polished & anodized, but all the silver ones i've ever seen, and i /have/ looked since we first
discussed this, have definitely been anodized.

> surface rim displays electrical continuity with a flashlight battery on its bead edge.

what does that prove? laquer and anodizing are both insulators. if you were trying to say that your
rims are polished, as is an old fiamme rim i have, then it will conduct on any surface and you
should readily see that.

>
>
>>I'm not sure if it's still up, but there was a very illustrative photo that showed the effect of
>>microstructure on rim failure:
>
>
>>in ASCII: The more common failure:
>
> _______________ crack
>
>> ______ ______ / \ / \ / \ / \ ___| | ____| |____ crack
>> | | | |
>> \ / \ /
>> \______/---- \______/
>
> _______________ crack
>
>
>>Lousy drawing, but this is supposed to show the photo with the two cracks initiating at the
>>eyelet. This is important because if you look at an anodized rim with a magnifier, [silver 517
>>being a classic example], you will see cracks in the anodizing *radiating* around the eyelet where
>>it has been punched through the rim. Straight out of the factory. Again, the anodizing cracks
>>exactly radiate around the spoke hole.
>
>
> You'll find that these cracks are aligned with extrusion marks and the cracks of interest are
> those across bridging stresses from edge to edge of the rim, there being significantly less
> bending stress between spokes.

i think we're on the same page, but which paragraph? yes, the cracks that support the "anodizing
only" hypothesis /do/ share the same axis as extrusion, but there's no definitive causal
relationship between the two. i guarantee that a "bad" extrusion, unanodized, will fail in axactly
the same way as your diagram, whereas a "good" extrusion, anodized, will not, or at least, not
during a normal component lifetime. the "pull-through" cracks at the top & bottom of your diagram
are not caused by cracking of the anodizing radiating from the spoke hole.

> That riveting eyelets and sockets causes crazing is not unusual, however, the cracks of
> interest are those that lie across principal bending planes. These are the ones that propagate
> into the metal.

you would expect, but not exclusively, which where my original diagram and the photo that it's based
on came from.

> Non anodized rims having no crust do not develop cracks as readily although cracking is possible
> with cyclic overload. Steady stress great enough to cause cracks would cause immediate failure
> similarly to spoke failure.
>
>
>>If anodizing were to be the sole cause of cracking, one would therefore expect to see the cracking
>>exactly axial with the lines of the cracked anodizing, as we see for the crack on the left. And
>>there would be no variation is this failure mode.
>
>
> Not so. Those cracks are not in line with the principal stress,

how not so? if the r/h crack in my diagram is not in line with the principal stress, then doesn't it
argue a secondary cracking mechanism?

> however, there have been star burst failures on rims with sufficiently thick anodizing.

see above. yes, you /can/ see failures like that, and yes, that /would/ be anodizing induced.

>
>
>>But on the right, this photo also showed cracking *tangential* to the spoke eyelet - i.e. /not/
>>following the radial cracks in the anodizing but following inherent flaws in the metal's extruded
>>microstructure.
>
>
> These all ran along the direction of extrusion, finally breaking across the rim the slender bridge
> they made of the mid section of the rim. This is one of the inherent disadvantages of extrusions.

extrusions are not inherantly flawed. indeed, the opposite is often true. flaws come with bad
processing, bad q.c. and bad material selection.

>
>
>>One *cannot* therefore solely attribute cracking simply to anodizing, whether it be hard, silver,
>>black or purple. There don't seem to be any real micrographs on the net showing what extruded
>>material looks like, but this is a good representation:
>
>
> http://www.stud.ntnu.no/~fjeldly/forming.html
>
>
>>Just like a piece of wood is easy to split along its grain, so can be a faulty extrusion.
>
>
> Or for that matter a good extrusion.

not if properly done.

>
>
>>The ma40 was junk. Just throw it away. No, most modern rims do not have this problem.
>
>
> Oh BS! A modern rim with anodizing presents the same failure.

since when? what's a current anodized rim cracking failure rate? how does that compare to the same
alloy unanodized? that's an entirely unsupported assumption.

> The difference is that manufacturers are cutting back on anodizing thickness.

measurements please.

fyi, mavic & ambrosio are introducing shot peening and other "kinetic" compressive residual
stress surface treatments. that should mitigate any last fear you have about premature fatigue in
modern rims.

>
>
> Jobst Brandt jobst.brandt@stanfordalumni.org

anonymous writes:

>> ...A modern rim with anodizing presents the same failure. The difference is that manufacturers
>> are cutting back on anodizing thickness.

> Or perhaps, having learned that there is a problem, they are at last attempting to engineer for an
> acceptable result with anodizing? This still begs the question of why to bother with anodization
> in this application at all, of course.

Currently black is beautiful, be that rims tires or SUV's (with blackened windows). You see even
Avocet knuckled under and blackened their great IRC made tires and claims to have has an immediate
jump in sales, although I doubt it. There is no equal to anodizing for durability and easy
application for blackening rims. As you see, riders were ready to pay at least 50% more for the MA-2
when it it was made black and labeled MA-40.

The same people who brought us the cracking hard anodized rims seem not to have lost any credibility
with their new gimmicks, such as wheels with names that defy pronunciation. Ksyrium, give me a
break, oops, that's a station wagon in France.

Just think, you can get Mavic rims that have "SUP" "MAXTAL" "UB" "FTSL" "QRM" "FORE" "ISM" "150PLUS"
"ZIRCAL" and "SSC". Its obvious that an MA-2 is no place, having none of these features and costing
under $30.

Jobst Brandt jobst.brandt@stanfordalumni.org

jobst.brandt@stanfordalumni.org wrote:
> anonymous writes:
>
>
>>>Oh? If all that welding, machining and heat treatment isn't a huge waste. Suckers!!!
>
>
>>Oh and the seam welding and machining is a waste too? Give me a break
>
>
> And what problem did these expensive adjuncts solve? You probably did not ride on rims that were
> not welded for any reasonable sampling. MA-2 rims and their equals for tubulars were used for
> about 50 years with no problem. Besides, the alloys used are not heat treatable. We went through
> that a few years back. Why would you want to heat treat aluminum rims?

ho ho ho, you jest, yes?

> I think you'll believe anything manufacturers put out as a marketing gimmick. People actually
> believed Rolf's claim that his wheels, having laterally paired spokes, prevented shimmy.
>
> Jobst Brandt jobst.brandt@stanfordalumni.org

jobst.brandt@stanfordalumni.org writes:

>>> ...A modern rim with anodizing presents the same failure. The difference is that manufacturers
>>> are cutting back on anodizing thickness.
>
>> Or perhaps, having learned that there is a problem, they are at last attempting to engineer for
>> an acceptable result with anodizing? This still begs the question of why to bother with
>> anodization in this application at all, of course.
>
> Currently black is beautiful, be that rims tires or SUV's (with blackened windows). You see even
> Avocet knuckled under and blackened their great IRC made tires and claims to have has an immediate
> jump in sales, although I doubt it.

Did they also make the tread thinner? I got only 1500 miles out of the last two rear (folding)
Road tires.

"Richard Ney" <rtn@pobox.com> wrote in
news:EH6Gb.4754$XF6.103369@typhoon.sonic.net:

> jobst.brandt@stanfordalumni.org writes:
>
>> You see even Avocet knuckled under and blackened their great IRC made tires and claims to have
>> has an immediate jump in sales, although I doubt it.
>
> Did they also make the tread thinner? I got only 1500 miles out of the last two rear (folding)
> Road tires.
>

Hey, dude!

Obviously, you haven't been in the game with your eyes open long enough to know about the differences between the old seam rims of yesterday and the machined seamed rims of today. So, I'll lay it out for you so you can stop deceiving your customers that the old rims are better than new.

1) Buy a oldie rim with a seam that you can actually feel when you run your fingers across the seam.
2) Buy a new rim with the seam welded and machined flat.
3) Now, when you brake with the old rim, you feel a thud, thud, thud every time the wheel goes around to hit the brake pad. Compare that to the smoothness of a rim with a flat and machined rim.

You and Jobst are totally WRONG on this one. And it doesn't take a freaking "I got a Stanford degree" to see that.

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

> Jobst Brandt wrote:
> > anonymous writes:
> >
> > >> Oh? If all that welding, machining and heat treatment isn't a huge waste. Suckers!!!
> >
> > > Oh and the seam welding and machining is a waste too? Give me a break
> >
> > And what problem did these expensive adjuncts solve? You probably did not ride on rims that
> > were not welded for any reasonable sampling. MA-2 rims and their equals for tubulars were used
> > for about 50 years with no problem. Besides, the alloys used are not heat treatable. We went
> > through that a few years back. Why would you want to heat treat aluminum rims? I think you'll
> > believe anything manufacturers put out as a marketing gimmick. People actually believed Rolf's
> > claim that his wheels, having laterally paired spokes, prevented shimmy. Jobst Brandt
> > jobst.brandt@stanfordalumni.org
>
> HAHAH! Whatever dude! The seam is machined for better braking. Now, you'll NEVER get rims that
> stick at the seam. But according to you its all marketing. Geez! Get a clue!

The anonymous Christmas troll reveals himself for what he is.

The one in need of the clue is yourself, rumdude. Why are rims machined? Because anodized sidewalls
provide miserable and dangerous wet weather braking characteristics. A few high-level pro racer
crashes that caused injury pointed this out very early in the game, and pro mechanics started taking
sandpaper to the braking surfaces. But that made the rims look ****ty, and customers complained
after their expensive rims started to look bad. Anodized rims also tend to cause brake squeal and
eat brake pads for lunch, which didn't sit well with the manufacturers of dual pivot brakes.

One of Mavic's owners is a metal finishing company specializing in anodizing (hello!) and the
company had to do something or start losing market share. They weren't going to stop anodizing, so
Plan B was to machine the sidewalls. This solved the bad braking, squealing and early pad death- but
at the cost of thin areas on the rims that wore through quicker.

So, basically for fashion- because red and green and black and whatever rims look cooler than
polished silver ones, we all get to buy inferior products that will crack and fail on us, and cost
twice as much. Cool! So, Rum-pot-stiltskin, have yourself a merry little Christmas and if you're
really good, Santa will bring you a pair of MA-2s. If you've been bad, MA-40s.