mavic rims don't *all* suck

Discussion in 'Cycling Equipment' started by Dvt, Feb 26, 2004.

  1. James Thomson <[email protected]> wrote:
    > "Jay Beattie" <[email protected]> wrote:

    > > AFAIK, all the predecessors and permutations of the MA2 (Elan, ModE, Mod3, Mod4, E2, MA2, G40,
    > > MA40) had the same two-piece, spoke socket and stainless steel rivet (eyelet) arrangement. You
    > > could not buy them with just a socket, or just a rivet or in plain steel.

    > Single-eyelet MA2s have been available on the British market in the past. I don't remember any
    > difference in labelling between the single eyelet model and the more common double eyelet version,
    > but I don't have an example on hand to compare.

    The original "MA" rim only had a single eyelet.

    The predecessor of the MA2 was the socketed (double-eyelet) G40. GP4 was the tubular version. All
    the G40, MA2, and MA40 rims I've seen have had similar socketed construction. I have not seen as
    many rims as some of you veterans, and I don't go peeling tires off rims to check.

    I'd believe pretty much anything Damon Rinard said over anything Bike Pro said. Bike Pro had a
    tendency to mistake precision for accuracy. Also, the guy who wrote the catalog and web site text
    used paragraph breaks so sparingly you'd think they were made of platinum, or old-stock MA-2s.

    Ah, shit! I understand the rim weight issue now. Look at the table at
    http://www.bikepro.com/products/rims/rimtables.html The entry for the MA-2 looks like this:

    With Weight per
    Spoke Drilling &
    Eyelets? Finish Weight

    Mavic ... 2-piece 464.0 g MA 2 Double Wall 473.5 g Stainless Steel 485.5 g

    Perhaps Carl mistakenly read the three lines as three types of rims. The "Spoke Eyelets" column is
    all one phrase: "2-piece double wall stainless steel" The Weight column entries are the weights of
    32, 36, and 40 hole rims. This is obvious from some of the other lines where the number of weights
    matches the number of hole drillings.

    The next entry is for the MA-40 and the weights are 472.5,
    449.9, 477.5. They're not even monotonically increasing with the number of holes/eyelets - that
    tells you something about variations in rim weight and the absurdity of weighing rims to a tenth
    of a gram right there.
     


  2. I wrote:
    > The original "MA" rim only had a single eyelet. The predecessor of the MA2 was the socketed (double-
    > eyelet) G40. GP4 was the tubular version. All the G40, MA2, and MA40 rims I've seen have had
    > similar socketed construction.

    Before the waters get muddied even further, I meant predecessor in terms of shape and socketedness;
    the GP4, G40, and MA40 were dark grey hard anodized, the MA and MA2 were not, being rather some sort
    of silvery color that other people can debate as they wish. ------------ And now a word from our
    sponsor ------------------ Want to have instant messaging, and chat rooms, and discussion groups for
    your local users or business, you need dbabble! -- See
    http://netwinsite.com/sponsor/sponsor_dbabble.htm ----
     
  3. Jay Beattie

    Jay Beattie Guest

    "Benjamin Weiner" <[email protected]> wrote in message
    news:[email protected]...
    > I wrote:
    > > The original "MA" rim only had a single eyelet. The predecessor of the MA2 was the socketed (double-
    > > eyelet)
    G40.
    > > GP4 was the tubular version. All the G40, MA2, and MA40 rims
    I've
    > > seen have had similar socketed construction.
    >
    > Before the waters get muddied even further, I meant predecessor in terms of shape and
    > socketedness; the GP4, G40, and MA40 were dark grey hard anodized, the MA and MA2 were not, being
    > rather some sort of silvery color that other people can debate as they wish.

    AFAIK, the succession of this design was Elan, Mod E, E2, MA2, GP4/G40 (anodized), MA4 (re-label of
    G40) -- along with various other Mods with larger widths for touring and tandems. I never saw an
    "MA" with single eyelets, which is significant to me because I was building a lot of wheels in the
    late '70s and early '80s for a local shop and friends -- mostly using Mavic and Super Champion rims.
    Does anyone own one of these elusive single eyelet MA rims? -- Jay Beattie.
     
  4. Matt O'Toole

    Matt O'Toole Guest

    Benjamin Weiner wrote:

    > The next entry is for the MA-40 and the weights are 472.5,
    > 449.9, 477.5. They're not even monotonically increasing with the number of holes/eyelets - that
    > tells you something about variations in rim weight and the absurdity of weighing rims to a
    > tenth of a gram right there.

    Well, I tried to point this out -- that differences in weight are normal, due to the process
    (extrusion) used to make rims. So there's a difference even before the number of holes and eyelets
    are considered. I've personally found "identical" rims that were over an ounce apart.

    Matt O.
     
  5. Carl Fogel

    Carl Fogel Guest

    Benjamin Weiner <[email protected]> wrote in message news:<[email protected]>...
    > James Thomson <[email protected]> wrote:
    > > "Jay Beattie" <[email protected]> wrote:
    >
    > > > AFAIK, all the predecessors and permutations of the MA2 (Elan, ModE, Mod3, Mod4, E2, MA2, G40, MA40) had the same two-piece, spoke socket and stainless steel rivet (eyelet) arrangement. You could not buy them with just a socket, or just a rivet or in plain steel.
    >
    > > Single-eyelet MA2s have been available on the British market in the past. I don't remember any difference in labelling between the single eyelet model and the more common double eyelet version, but I don't have an example on hand to compare.
    >
    > The original "MA" rim only had a single eyelet.
    >
    > The predecessor of the MA2 was the socketed (double-eyelet) G40. GP4 was the tubular version. All the G40, MA2, and MA40 rims I've seen have had similar socketed construction. I have not seen as many rims as some of you veterans, and I don't go peeling tires off rims to check.
    >
    > I'd believe pretty much anything Damon Rinard said over anything Bike Pro said. Bike Pro had a tendency to mistake precision for accuracy. Also, the guy who wrote the catalog and web site text used paragraph breaks so sparingly you'd think they were made of platinum, or old-stock MA-2s.
    >
    > Ah, shit! I understand the rim weight issue now. Look at the table at http://www.bikepro.com/products/rims/rimtables.html The entry for the MA-2 looks like this:
    >
    > With Weight per
    > Spoke Drilling &
    > Eyelets? Finish Weight
    >
    > Mavic ... 2-piece 464.0 g MA 2 Double Wall 473.5 g Stainless Steel 485.5 g
    >
    > Perhaps Carl mistakenly read the three lines as three types of rims. The "Spoke Eyelets" column is all one phrase: "2-piece double wall stainless steel" The Weight column entries are the weights of 32, 36, and 40 hole rims. This is obvious from some of the other lines where the number of weights matches the number of hole drillings.
    >
    > The next entry is for the MA-40 and the weights are 472.5,
    > 449.9, 477.5. They're not even monotonically increasing with the number of holes/eyelets - that tells you something about variations in rim weight and the absurdity of weighing rims to a tenth of a gram right there.

    Dear Benjamin,

    I think that you're right, having looked at the tables again with what you wrote in mind, and that I was mistaken.

    (Big surprise!)

    What troubles me is that the weights, as you point out, do not increase or decrease in any clear pattern if the number of holes is what's affecting things, at least not when I look at more of the samples. Sometimes they go up, sometimes they go down. Mostly they change about ten grams.

    But I'm having trouble with the idea that drilling four holes through double-wall rims alone can account for what look like generally 10-gram differences.

    A typical Presta valve weighed on electronic scales is only about 2 grams, while a thick Schrader valve is only about 4 grams.

    Both kinds of valves contain far more metal than a spoke-hole, even though they're hollow, but they amount to far less than ten grams.

    That is, I doubt that each of four new spoke holes in a double-wall rim removes 2.5 grams of metal when a whole presta valve is only 2 grams.

    As a logic check, consider that the MA 2 rims are around 460 grams with 32 to 40 holes.

    There's room to drill eight new spoke holes between the existing spoke holes on a 32-hole rim, around 256 holes.

    If each new hole removed 2.5 grams of metal, 256 new spoke holes in a line would make the 460 gram rim vanish, so the amount removed by drilling a hole must be far less than the 2.5 grams needed to account for 4 more spoke holes causing a 10 gram weight change.

    Unfortunately, this leads to the idea that Mavic just couldn't control its manufacturing process any better than a haphazard 10% variation in finished weight. I doubt that this is the case and suspect that there were some kind of silent but deliberate changes in the manufacturing process that led to weights clustered around roughly 460, 470, and 480 gram rims.

    Damon Rinard's rim-weight table seems to lump all MA 2 rims together, but his weights seem to follow much the same three-tier pattern as the BikePro catalogue. (His use of two different scales might also affect things).

    So I not only think that I was mistaken and that you're right about only one kind of eyelet, but now I'm puzzled.

    Were there three kinds of MA 2 rims that could be distinguished by weight? If so, what accounted for the ten-gram differences?

    The extra four spoke holes alone seem unlikely candidates, but perhaps something else changed along with the drilling pattern? Bigger spoke holes all around? Different eyelets all around? A different polishing process (or anodizing process for anodized rims)?

    Or are we really riding on rims that may vary ten, twenty, thirty, or even forty grams without any silent design changes?

    Again, I have trouble believing that two rims manufactured with the same process will vary even twenty grams--that's tacking the equivalent of twenty Presta valves to a part that seems to be rather precisely built.

    The idea that the rim-strip extrusion dies wear and produce thicker and thicker rim strips is plausible, but do the manufacturers really let things wear until the raw strips are 10% heavier?

    Perhaps some kindly bicycle dealer will take a dozen new and supposedly identical rims, fling them on a postal scale, and let us know what kind of variation is current?

    I'm plumb baffled. (But, thanks to you, no longer as badly mistaken.)

    Carl Fogel
     
  6. Carl Fogel

    Carl Fogel Guest

    [email protected] (Carl Fogel) wrote in message news:<[email protected]>...

    [snip my imbecility]

    Dear Benjamin,

    Aaargh!

    I was wrong and you were right--and then I was even wronger again.

    While drilling out four more spoke holes is unlikely to amount to the typical 10-
    gram changes in the BikePro rim table, adding the four eyelet thingies might well
    account for a 10-gram weight change in the other direction. Unlike the
    comparatively small drilled-out double-wall sections, the eyelets are more the
    size of a 2-gram Presta valve.

    Now I can go to bed.

    Aaaargh!

    Carl Fogel
     
  7. Dianne_1234

    Dianne_1234 Guest

    On 5 Mar 2004 19:08:26 -0800, [email protected] (Carl Fogel)
    wrote:

    >Dear Benjamin,
    >
    >I think that you're right, having looked at the tables
    >again with what you wrote in mind, and that I was mistaken.
    >
    >(Big surprise!)
    >
    >What troubles me is that the weights, as you point out, do
    >not increase or decrease in any clear pattern if the number
    >of holes is what's affecting things, at least not when I
    >look at more of the samples. Sometimes they go up,
    >sometimes they go down. Mostly they change about ten grams.
    >
    >But I'm having trouble with the idea that drilling four
    >holes through double-wall rims alone can account for what
    >look like generally 10-gram differences.
    >
    >A typical Presta valve weighed on electronic scales is
    >only about 2 grams, while a thick Schrader valve is only
    >about 4 grams.
    >
    >Both kinds of valves contain far more metal than a spoke-
    >hole, even though they're hollow, but they amount to far
    >less than ten grams.
    >
    >That is, I doubt that each of four new spoke holes in a double-
    >wall rim removes 2.5 grams of metal when a whole presta
    >valve is only 2 grams.
    >
    >As a logic check, consider that the MA 2 rims are around
    >460 grams with 32 to 40 holes.
    >
    >There's room to drill eight new spoke holes between the
    >existing spoke holes on a 32-hole rim, around 256 holes.
    >
    >If each new hole removed 2.5 grams of metal, 256 new spoke
    >holes in a line would make the 460 gram rim vanish, so the
    >amount removed by drilling a hole must be far less than the
    >2.5 grams needed to account for 4 more spoke holes causing
    >a 10 gram weight change.
    >
    >Unfortunately, this leads to the idea that Mavic just
    >couldn't control its manufacturing process any better than
    >a haphazard 10% variation in finished weight. I doubt that
    >this is the case and suspect that there were some kind of
    >silent but deliberate changes in the manufacturing process
    >that led to weights clustered around roughly 460, 470, and
    >480 gram rims.
    >
    >Damon Rinard's rim-weight table seems to lump all MA 2 rims
    >together, but his weights seem to follow much the same three-
    >tier pattern as the BikePro catalogue. (His use of two
    >different scales might also affect things).
    >
    >So I not only think that I was mistaken and that you're
    >right about only one kind of eyelet, but now I'm puzzled.
    >
    >Were there three kinds of MA 2 rims that could be
    >distinguished by weight? If so, what accounted for the ten-
    >gram differences?
    >
    >The extra four spoke holes alone seem unlikely candidates,
    >but perhaps something else changed along with the drilling
    >pattern? Bigger spoke holes all around? Different eyelets
    >all around? A different polishing process (or anodizing
    >process for anodized rims)?
    >
    >Or are we really riding on rims that may vary ten,
    >twenty, thirty, or even forty grams without any silent
    >design changes?
    >
    >Again, I have trouble believing that two rims manufactured
    >with the same process will vary even twenty grams--that's
    >tacking the equivalent of twenty Presta valves to a part
    >that seems to be rather precisely built.
    >
    >The idea that the rim-strip extrusion dies wear and produce
    >thicker and thicker rim strips is plausible, but do the
    >manufacturers really let things wear until the raw strips
    >are 10% heavier?
    >
    >Perhaps some kindly bicycle dealer will take a dozen new
    >and supposedly identical rims, fling them on a postal
    >scale, and let us know what kind of variation is current?
    >
    >I'm plumb baffled. (But, thanks to you, no longer as badly
    >mistaken.)
    >
    >Carl Fogel

    I think someone mentioned here that some rim extrusion dies
    have more than one hole. Maybe they differ because of that?

    A rim side wall is about half an inch tall. If the extrusion
    tolerance were, say, +/- 0.005", then one hole might make a
    rim that much wider. Maybe even on both side walls?

    Can anyone calculate how much that much aluminum weighs?
     
  8. Dianne_1234

    Dianne_1234 Guest

    On Sat, 06 Mar 2004 07:27:57 -0600, dianne_1234
    <[email protected]> wrote:

    >I think someone mentioned here that some rim extrusion dies
    >have more than one hole. Maybe they differ because of that?
    >
    >A rim side wall is about half an inch tall. If the
    >extrusion tolerance were, say, +/- 0.005", then one hole
    >might make a rim that much wider. Maybe even on both
    >side walls?
    >
    >Can anyone calculate how much that much aluminum weighs?

    Here's my try:

    side wall height, cm 1.3 circumferential length, cm 198.8
    delta width, cm 0.0127 delta volume, cc 3.282 density, g/cc
    2.7 delta mass, g 8.86

    If this is correct, then a small variation in extruded
    thickness (.005") might make a 8 or 9 gram difference in
    rim weight.

    This is just one guess; you could guess other variables. You
    could pretend the wall thickness varied by more or less than
    0.005", or that the spoke hub-facing wall of the rim is the
    one that varied, etc.
     
  9. Matt O'Toole

    Matt O'Toole Guest

    dianne_1234 wrote:

    > On Sat, 06 Mar 2004 07:27:57 -0600, dianne_1234
    > <[email protected]> wrote:

    >> I think someone mentioned here that some rim extrusion
    >> dies have more than one hole. Maybe they differ because
    >> of that?

    It's possible.

    > Here's my try:
    >
    > side wall height, cm 1.3 circumferential length, cm 198.8
    > delta width, cm 0.0127 delta volume, cc 3.282 density,
    > g/cc 2.7 delta mass, g 8.86
    >
    > If this is correct, then a small variation in extruded
    > thickness (.005") might make a 8 or 9 gram difference in
    > rim weight.
    >
    > This is just one guess; you could guess other variables.
    > You could pretend the wall thickness varied by more or
    > less than 0.005", or that the spoke hub-facing wall of the
    > rim is the one that varied, etc.

    For the third time, yes. Extrusion dies wear with use. Early
    production is thinner in cross section and lighter, later
    production fatter and heavier. This is why rim weights vary,
    aside from things like the number of eyelets.

    Matt O.
     
  10. Carl Fogel

    Carl Fogel Guest

    dianne_1234 <[email protected]> wrote in message news:<[email protected]>...
    > On Sat, 06 Mar 2004 07:27:57 -0600, dianne_1234
    > <[email protected]> wrote:
    >
    > >I think someone mentioned here that some rim extrusion
    > >dies have more than one hole. Maybe they differ because
    > >of that?
    > >
    > >A rim side wall is about half an inch tall. If the
    > >extrusion tolerance were, say, +/- 0.005", then one hole
    > >might make a rim that much wider. Maybe even on both
    > >side walls?
    > >
    > >Can anyone calculate how much that much aluminum weighs?
    >
    > Here's my try:
    >
    > side wall height, cm 1.3 circumferential length, cm 198.8
    > delta width, cm 0.0127 delta volume, cc 3.282 density,
    > g/cc 2.7 delta mass, g 8.86
    >
    > If this is correct, then a small variation in extruded
    > thickness (.005") might make a 8 or 9 gram difference in
    > rim weight.
    >
    > This is just one guess; you could guess other variables.
    > You could pretend the wall thickness varied by more or
    > less than 0.005", or that the spoke hub-facing wall of the
    > rim is the one that varied, etc.

    Dear Dianne,

    The BikePro catalogue and link mention a possible 8 to 9%
    weight increase from worn dies:

    "We call this phenomena "extrusion wall thickness deviation"
    and have found that some rims with the same drilling can
    weigh up to 8 or 9 per cent more, though they appear to have
    the same shape." from
    http://www.bikepro.com/products/rims/rimover.html

    The trouble is that BikePro lists no examples of what
    they found.

    Damon Rinard's table shows MA 2 rims weighing
    444,451,466,454,481,481 grams.

    See: http://www.sheldonbrown.com/rinard/weights.htm

    The range from 444 to 481 grams is 37 grams, or an increase
    of 37/444 = 8.33%.

    Damon's list for the Mavic Open Pro shows weights of
    405,424,424,437,440,441,445 420, an increase of 40 grams
    from 405 to 445, a 9.87% increase.

    For the Mavic Open 4 CD, he lists 412,456,456,437,434, an
    increase of 44 grams from 412 to 456, or 10.68%.

    For the Mavic MA 40, he shows 471,476,482,509,513,513, an
    increase of 42 grams from 471 to 513, or 8.91%.

    So a weight range of 8-10% possibly resulting from die wear
    seems at first glance to be borne out by Damon's tables.

    But his tables show no drillings, which the BikePro
    catalogue indicates account for about 10 grams by
    themselves. (I suspect that 4 more holes paradoxically
    increase a Mavic MA 2's weight by 10 grams because the
    weight drilled away in 8 new spoke holes in thin double-wall
    aluminum is exceeded by the weight of four much larger two-
    piece steel eyelet thingies.)

    And I'm still puzzled by Damon's weights, which start twenty
    grams below the BikePro table and never quite reach the
    heaviest BikePro weight:

    Rinard BikePro MA 2 MA 2 445 444 455 451,454 465 466
    464 475 473.5 485 481,481 483.5

    Damon's table matches two out of three BikePro weights
    pretty well. What's curious is that he has two examples that
    were ten grams below the lightest weight from BikePro and
    another ten grams even lighter.

    One possibility is that Damon's switch from an electronic
    scale to a triple-beam balance needed better calibration and
    spread things out.

    Or the BikePro scales read 20 grams higher than Damon's
    scales. (Mavic claimed a weight of 460, according to
    Damon's table.)

    Another possibility is that, as Damon says, he weighed
    almost all of these things himself, but the popular Mavic MA
    2 list might have included weights from "Neil Aldridge, Jim
    Baker, Steve Cohen, Philippe Courrier and Russell Seaton,"
    whom he thanks at the end of the rim section for
    contributing. It's unclear whether they contributed rims or
    data on the rims from their scales.

    The die-wear explanation seems plausible, but it only
    explains rims getting heavier. It doesn't explain rims on
    Damon's table that weighed 20 grams less than what Mavic
    claimed and what BikePro weighed.

    Of course, this is all an excitingly academic fuss that
    started when I quibbled with Jobst's comment that rims weigh
    exactly the same after anodizing.

    The chief thing that I noticed in the BikePro rim section
    was their claim that the MA 2 was anodized and then drilled
    and rolled:

    "The MA2 is a Box shaped extrusion, with the three exterior
    surfaces, both side walls and the hub facing side of the
    spoke bed wall high polished to a bright Silver aluminum
    then Clear anodized to harden and preserve the finish. The
    extrusion is then drilled for the spoke and valve holes and
    rolled into its hoop shape." from
    http://www.bikepro.com/products/rims/mavicroad.html

    The MA 40 was hard anodized after rolling and drilling:

    "The MA40 rim is based on the same extrusion used in the
    MA2. The only obvious variation between the two rims is
    their surface treatment. They may each be made of a
    different series of aluminum alloy, but we'll never know
    because the alloy composition is kept secret."

    "The MA40 has their 'CD' or 'couche dure' treatment, what in
    the United States is called a hard anodized finish and is
    dark Grey in color. The anodizing on the MA40 is performed
    after it is hooped and drilled." from
    http://www.bikepro.com/products/rims/mavicroad.html

    Carl Fogel
     
  11. Jim Beam

    Jim Beam Guest

    Carl Fogel wrote:
    > dianne_1234 <[email protected]> wrote in message
    > news:<[email protected]>...
    >
    >>On Sat, 06 Mar 2004 07:27:57 -0600, dianne_1234
    >><[email protected]> wrote:
    >>
    >>
    >>>I think someone mentioned here that some rim extrusion
    >>>dies have more than one hole. Maybe they differ because
    >>>of that?
    >>>
    >>>A rim side wall is about half an inch tall. If the
    >>>extrusion tolerance were, say, +/- 0.005", then one hole
    >>>might make a rim that much wider. Maybe even on both
    >>>side walls?
    >>>
    >>>Can anyone calculate how much that much aluminum weighs?
    >>
    >>Here's my try:
    >>
    >>side wall height, cm 1.3 circumferential length, cm 198.8
    >>delta width, cm 0.0127 delta volume, cc 3.282 density,
    >>g/cc 2.7 delta mass, g 8.86
    >>
    >>If this is correct, then a small variation in extruded
    >>thickness (.005") might make a 8 or 9 gram difference in
    >>rim weight.
    >>
    >>This is just one guess; you could guess other variables.
    >>You could pretend the wall thickness varied by more or
    >>less than 0.005", or that the spoke hub-facing wall of the
    >>rim is the one that varied, etc.
    >
    >
    > Dear Dianne,
    >
    > The BikePro catalogue and link mention a possible 8 to 9%
    > weight increase from worn dies:
    >
    > "We call this phenomena "extrusion wall thickness
    > deviation" and have found that some rims with the same
    > drilling can weigh up to 8 or 9 per cent more, though they
    > appear to have the same shape." from
    > http://www.bikepro.com/products/rims/rimover.html
    >
    > The trouble is that BikePro lists no examples of what
    > they found.
    >
    > Damon Rinard's table shows MA 2 rims weighing
    > 444,451,466,454,481,481 grams.
    >
    > See: http://www.sheldonbrown.com/rinard/weights.htm
    >
    > The range from 444 to 481 grams is 37 grams, or an
    > increase of 37/444 = 8.33%.
    >
    > Damon's list for the Mavic Open Pro shows weights of
    > 405,424,424,437,440,441,445 420, an increase of 40 grams
    > from 405 to 445, a 9.87% increase.
    >
    > For the Mavic Open 4 CD, he lists 412,456,456,437,434, an
    > increase of 44 grams from 412 to 456, or 10.68%.
    >
    > For the Mavic MA 40, he shows 471,476,482,509,513,513, an
    > increase of 42 grams from 471 to 513, or 8.91%.
    >
    > So a weight range of 8-10% possibly resulting from
    > die wear seems at first glance to be borne out by
    > Damon's tables.
    >
    > But his tables show no drillings, which the BikePro
    > catalogue indicates account for about 10 grams by
    > themselves. (I suspect that 4 more holes paradoxically
    > increase a Mavic MA 2's weight by 10 grams because the
    > weight drilled away in 8 new spoke holes in thin double-
    > wall aluminum is exceeded by the weight of four much
    > larger two-piece steel eyelet thingies.)
    >
    > And I'm still puzzled by Damon's weights, which start
    > twenty grams below the BikePro table and never quite reach
    > the heaviest BikePro weight:
    >
    > Rinard BikePro MA 2 MA 2 445 444 455 451,454 465 466
    > 464 475 473.5 485 481,481 483.5
    >
    > Damon's table matches two out of three BikePro weights
    > pretty well. What's curious is that he has two examples
    > that were ten grams below the lightest weight from BikePro
    > and another ten grams even lighter.
    >
    > One possibility is that Damon's switch from an electronic
    > scale to a triple-beam balance needed better calibration
    > and spread things out.
    >
    > Or the BikePro scales read 20 grams higher than Damon's
    > scales. (Mavic claimed a weight of 460, according to
    > Damon's table.)
    >
    > Another possibility is that, as Damon says, he weighed
    > almost all of these things himself, but the popular Mavic
    > MA 2 list might have included weights from "Neil Aldridge,
    > Jim Baker, Steve Cohen, Philippe Courrier and Russell
    > Seaton," whom he thanks at the end of the rim section for
    > contributing. It's unclear whether they contributed rims
    > or data on the rims from their scales.
    >
    > The die-wear explanation seems plausible, but it only
    > explains rims getting heavier. It doesn't explain rims on
    > Damon's table that weighed 20 grams less than what Mavic
    > claimed and what BikePro weighed.

    matt's comment about dies wearing is absolutely correct. any
    variance in the weights you're seeing in these tables is
    either due to scale calibration or simply scatter because
    the sample size is not large enough to accurately determine
    a good mean. as a manufacturer's quoted measures /are/
    typically a mean. who knows what they regard as an
    acceptable standard deviation. if they didn't quote a mean,
    they'd have to quote a range. can you imagine the, er,
    "uncertainty" that would be caused by quoting a range of
    weights for rims? suddenly, all the "light" ones would sell
    and the "heavy" ones would not. can't see that policy
    surviving very long.

    >
    > Of course, this is all an excitingly academic fuss that
    > started when I quibbled with Jobst's comment that rims
    > weigh exactly the same after anodizing.
    >
    > The chief thing that I noticed in the BikePro rim section
    > was their claim that the MA 2 was anodized and then
    > drilled and rolled:
    >
    > "The MA2 is a Box shaped extrusion, with the three
    > exterior surfaces, both side walls and the hub facing side
    > of the spoke bed wall high polished to a bright Silver
    > aluminum then Clear anodized to harden and preserve the
    > finish. The extrusion is then drilled for the spoke and
    > valve holes and rolled into its hoop shape." from
    > http://www.bikepro.com/products/rims/mavicroad.html

    i may be wrong, but i doubt /any/ rim is hooped after
    anodizing. anodizing is too brittle and the bending will
    expose unprotected metal. completely defeats the point.

    >
    > The MA 40 was hard anodized after rolling and drilling:
    >
    > "The MA40 rim is based on the same extrusion used in the
    > MA2. The only obvious variation between the two rims is
    > their surface treatment. They may each be made of a
    > different series of aluminum alloy, but we'll never know
    > because the alloy composition is kept secret."
    >
    > "The MA40 has their 'CD' or 'couche dure' treatment, what
    > in the United States is called a hard anodized finish and
    > is dark Grey in color. The anodizing on the MA40 is
    > performed after it is hooped and drilled." from
    > http://www.bikepro.com/products/rims/mavicroad.html

    that bit at least is correct.

    >
    > Carl Fogel
     
  12. G.T.

    G.T. Guest

    jim beam wrote:
    > Carl Fogel wrote:
    >
    >> dianne_1234 <[email protected]> wrote in
    >> message
    >> news:<[email protected]>...
    >>
    >>> On Sat, 06 Mar 2004 07:27:57 -0600, dianne_1234
    >>> <[email protected]> wrote:
    >>>
    >>>
    >>>> I think someone mentioned here that some rim extrusion
    >>>> dies have more than one hole. Maybe they differ because
    >>>> of that?
    >>>>
    >>>> A rim side wall is about half an inch tall. If the
    >>>> extrusion tolerance were, say, +/- 0.005", then one
    >>>> hole might make a rim that much wider. Maybe even on
    >>>> both side walls? Can anyone calculate how much that
    >>>> much aluminum weighs?
    >>>
    >>>
    >>> Here's my try:
    >>>
    >>> side wall height, cm 1.3 circumferential length, cm
    >>> 198.8 delta width, cm 0.0127 delta volume, cc 3.282
    >>> density, g/cc 2.7 delta mass, g 8.86
    >>>
    >>> If this is correct, then a small variation in extruded
    >>> thickness (.005") might make a 8 or 9 gram difference in
    >>> rim weight. This is just one guess; you could guess
    >>> other variables. You could pretend the wall thickness
    >>> varied by more or less than 0.005", or that the spoke
    >>> hub-facing wall of the rim is the one that varied, etc.
    >>
    >>
    >>
    >> Dear Dianne,
    >>
    >> The BikePro catalogue and link mention a possible 8 to 9%
    >> weight increase from worn dies:
    >>
    >> "We call this phenomena "extrusion wall thickness
    >> deviation" and have found that some rims with the same
    >> drilling can weigh up to 8 or 9 per cent more, though
    >> they appear to have the same shape." from
    >> http://www.bikepro.com/products/rims/rimover.html
    >>
    >> The trouble is that BikePro lists no examples of what
    >> they found.
    >>
    >> Damon Rinard's table shows MA 2 rims weighing
    >> 444,451,466,454,481,481 grams. See:
    >> http://www.sheldonbrown.com/rinard/weights.htm
    >>
    >> The range from 444 to 481 grams is 37 grams, or an
    >> increase of 37/444 = 8.33%. Damon's list for the Mavic
    >> Open Pro shows weights of 405,424,424,437,440,441,445
    >> 420, an increase of 40 grams from 405 to 445, a 9.87%
    >> increase.
    >>
    >> For the Mavic Open 4 CD, he lists 412,456,456,437,434, an
    >> increase of 44 grams from 412 to 456, or 10.68%.
    >>
    >> For the Mavic MA 40, he shows 471,476,482,509,513,513, an
    >> increase of 42 grams from 471 to 513, or 8.91%.
    >>
    >> So a weight range of 8-10% possibly resulting from die
    >> wear seems at first glance to be borne out by Damon's
    >> tables.
    >>
    >> But his tables show no drillings, which the BikePro
    >> catalogue indicates account for about 10 grams by
    >> themselves. (I suspect that 4 more holes paradoxically
    >> increase a Mavic MA 2's weight by 10 grams because the
    >> weight drilled away in 8 new spoke holes in thin double-
    >> wall aluminum is exceeded by the weight of four much
    >> larger two-piece steel eyelet thingies.)
    >>
    >> And I'm still puzzled by Damon's weights, which start
    >> twenty grams below the BikePro table and never quite
    >> reach the heaviest BikePro weight:
    >>
    >> Rinard BikePro MA 2 MA 2 445 444 455 451,454 465
    >> 466 464 475 473.5 485 481,481 483.5
    >>
    >> Damon's table matches two out of three BikePro weights
    >> pretty well. What's curious is that he has two examples
    >> that were ten grams below the lightest weight from
    >> BikePro and another ten grams even lighter.
    >>
    >> One possibility is that Damon's switch from an electronic
    >> scale to a triple-beam balance needed better calibration
    >> and spread things out. Or the BikePro scales read 20
    >> grams higher than Damon's scales. (Mavic claimed a weight
    >> of 460, according to Damon's table.)
    >>
    >> Another possibility is that, as Damon says, he weighed
    >> almost all of these things himself, but the popular Mavic
    >> MA 2 list might have included weights from "Neil
    >> Aldridge, Jim Baker, Steve Cohen, Philippe Courrier and
    >> Russell Seaton," whom he thanks at the end of the rim
    >> section for contributing. It's unclear whether they
    >> contributed rims or data on the rims from their scales.
    >>
    >> The die-wear explanation seems plausible, but it only
    >> explains rims getting heavier. It doesn't explain rims on
    >> Damon's table that weighed 20 grams less than what Mavic
    >> claimed and what BikePro weighed.
    >
    >
    > matt's comment about dies wearing is absolutely correct.
    > any variance in the weights you're seeing in these tables
    > is either due to scale calibration or simply scatter
    > because the sample size is not large enough to accurately
    > determine a good mean. as a manufacturer's quoted measures
    > /are/ typically a mean. who knows what they regard as an
    > acceptable standard deviation. if they didn't quote a
    > mean, they'd have to quote a range. can you imagine the,
    > er, "uncertainty" that would be caused by quoting a range
    > of weights for rims? suddenly, all the "light" ones would
    > sell and the "heavy" ones would not. can't see that policy
    > surviving very long.
    >
    >>
    >> Of course, this is all an excitingly academic fuss that
    >> started when I quibbled with Jobst's comment that rims
    >> weigh exactly the same after anodizing.
    >>
    >> The chief thing that I noticed in the BikePro rim section
    >> was their claim that the MA 2 was anodized and then
    >> drilled and rolled:
    >>
    >> "The MA2 is a Box shaped extrusion, with the three
    >> exterior surfaces, both side walls and the hub facing
    >> side of the spoke bed wall high polished to a bright
    >> Silver aluminum then Clear anodized to harden and
    >> preserve the finish. The extrusion is then drilled for
    >> the spoke and valve holes and rolled into its hoop
    >> shape." from
    >> http://www.bikepro.com/products/rims/mavicroad.html
    >
    >
    > i may be wrong, but i doubt /any/ rim is hooped after
    > anodizing. anodizing is too brittle and the bending will
    > expose unprotected metal. completely defeats the point.
    >

    Anodizing defeats the point in the first place. Do you
    really think manufacturers that promote anodization would do
    it the right way?

    The extrusion is usually anodized first in a long tank.

    Greg
     
  13. Carl Fogel

    Carl Fogel Guest

    jim beam <[email protected]> wrote in message news:<[email protected]>...
    > Carl Fogel wrote:
    > > dianne_1234 <[email protected]> wrote in
    > > message
    > > news:<[email protected]>...
    > >
    > >>On Sat, 06 Mar 2004 07:27:57 -0600, dianne_1234
    > >><[email protected]> wrote:
    > >>
    > >>
    > >>>I think someone mentioned here that some rim extrusion
    > >>>dies have more than one hole. Maybe they differ because
    > >>>of that?
    > >>>
    > >>>A rim side wall is about half an inch tall. If the
    > >>>extrusion tolerance were, say, +/- 0.005", then one
    > >>>hole might make a rim that much wider. Maybe even on
    > >>>both side walls?
    > >>>
    > >>>Can anyone calculate how much that much aluminum
    > >>>weighs?
    > >>
    > >>Here's my try:
    > >>
    > >>side wall height, cm 1.3 circumferential length, cm
    > >>198.8 delta width, cm 0.0127 delta volume, cc 3.282
    > >>density, g/cc 2.7 delta mass, g 8.86
    > >>
    > >>If this is correct, then a small variation in extruded
    > >>thickness (.005") might make a 8 or 9 gram difference in
    > >>rim weight.
    > >>
    > >>This is just one guess; you could guess other variables.
    > >>You could pretend the wall thickness varied by more or
    > >>less than 0.005", or that the spoke hub-facing wall of
    > >>the rim is the one that varied, etc.
    > >
    > >
    > > Dear Dianne,
    > >
    > > The BikePro catalogue and link mention a possible 8 to
    > > 9% weight increase from worn dies:
    > >
    > > "We call this phenomena "extrusion wall thickness
    > > deviation" and have found that some rims with the same
    > > drilling can weigh up to 8 or 9 per cent more, though
    > > they appear to have the same shape." from
    > > http://www.bikepro.com/products/rims/rimover.html
    > >
    > > The trouble is that BikePro lists no examples of what
    > > they found.
    > >
    > > Damon Rinard's table shows MA 2 rims weighing
    > > 444,451,466,454,481,481 grams.
    > >
    > > See: http://www.sheldonbrown.com/rinard/weights.htm
    > >
    > > The range from 444 to 481 grams is 37 grams, or an
    > > increase of 37/444 = 8.33%.
    > >
    > > Damon's list for the Mavic Open Pro shows weights of
    > > 405,424,424,437,440,441,445 420, an increase of 40 grams
    > > from 405 to 445, a 9.87% increase.
    > >
    > > For the Mavic Open 4 CD, he lists 412,456,456,437,434,
    > > an increase of 44 grams from 412 to 456, or 10.68%.
    > >
    > > For the Mavic MA 40, he shows 471,476,482,509,513,513,
    > > an increase of 42 grams from 471 to 513, or 8.91%.
    > >
    > > So a weight range of 8-10% possibly resulting from die
    > > wear seems at first glance to be borne out by Damon's
    > > tables.
    > >
    > > But his tables show no drillings, which the BikePro
    > > catalogue indicates account for about 10 grams by
    > > themselves. (I suspect that 4 more holes paradoxically
    > > increase a Mavic MA 2's weight by 10 grams because the
    > > weight drilled away in 8 new spoke holes in thin double-
    > > wall aluminum is exceeded by the weight of four much
    > > larger two-piece steel eyelet thingies.)
    > >
    > > And I'm still puzzled by Damon's weights, which start
    > > twenty grams below the BikePro table and never quite
    > > reach the heaviest BikePro weight:
    > >
    > > Rinard BikePro MA 2 MA 2 445 444 455 451,454 465
    > > 466 464 475 473.5 485 481,481 483.5
    > >
    > > Damon's table matches two out of three BikePro weights
    > > pretty well. What's curious is that he has two examples
    > > that were ten grams below the lightest weight from
    > > BikePro and another ten grams even lighter.
    > >
    > > One possibility is that Damon's switch from an
    > > electronic scale to a triple-beam balance needed better
    > > calibration and spread things out.
    > >
    > > Or the BikePro scales read 20 grams higher than Damon's
    > > scales. (Mavic claimed a weight of 460, according to
    > > Damon's table.)
    > >
    > > Another possibility is that, as Damon says, he weighed
    > > almost all of these things himself, but the popular
    > > Mavic MA 2 list might have included weights from "Neil
    > > Aldridge, Jim Baker, Steve Cohen, Philippe Courrier and
    > > Russell Seaton," whom he thanks at the end of the rim
    > > section for contributing. It's unclear whether they
    > > contributed rims or data on the rims from their scales.
    > >
    > > The die-wear explanation seems plausible, but it only
    > > explains rims getting heavier. It doesn't explain rims
    > > on Damon's table that weighed 20 grams less than what
    > > Mavic claimed and what BikePro weighed.
    >
    > matt's comment about dies wearing is absolutely correct.
    > any variance in the weights you're seeing in these tables
    > is either due to scale calibration or simply scatter
    > because the sample size is not large enough to accurately
    > determine a good mean. as a manufacturer's quoted measures
    > /are/ typically a mean. who knows what they regard as an
    > acceptable standard deviation. if they didn't quote a
    > mean, they'd have to quote a range. can you imagine the,
    > er, "uncertainty" that would be caused by quoting a range
    > of weights for rims? suddenly, all the "light" ones would
    > sell and the "heavy" ones would not. can't see that policy
    > surviving very long.
    >
    > >
    > > Of course, this is all an excitingly academic fuss that
    > > started when I quibbled with Jobst's comment that rims
    > > weigh exactly the same after anodizing.
    > >
    > > The chief thing that I noticed in the BikePro rim
    > > section was their claim that the MA 2 was anodized and
    > > then drilled and rolled:
    > >
    > > "The MA2 is a Box shaped extrusion, with the three
    > > exterior surfaces, both side walls and the hub facing
    > > side of the spoke bed wall high polished to a bright
    > > Silver aluminum then Clear anodized to harden and
    > > preserve the finish. The extrusion is then drilled for
    > > the spoke and valve holes and rolled into its hoop
    > > shape." from
    > > http://www.bikepro.com/products/rims/mavicroad.html
    >
    > i may be wrong, but i doubt /any/ rim is hooped after
    > anodizing. anodizing is too brittle and the bending will
    > expose unprotected metal. completely defeats the point.
    >
    > >
    > > The MA 40 was hard anodized after rolling and drilling:
    > >
    > > "The MA40 rim is based on the same extrusion used in the
    > > MA2. The only obvious variation between the two rims is
    > > their surface treatment. They may each be made of a
    > > different series of aluminum alloy, but we'll never know
    > > because the alloy composition is kept secret."
    > >
    > > "The MA40 has their 'CD' or 'couche dure' treatment,
    > > what in the United States is called a hard anodized
    > > finish and is dark Grey in color. The anodizing on the
    > > MA40 is performed after it is hooped and drilled." from
    > > http://www.bikepro.com/products/rims/mavicroad.html
    >
    > that bit at least is correct.
    >
    > >
    > > Carl Fogel

    Dear Jim,

    All I know is what I read in the papers . . . [Google for
    the rest, which has mostly been forgotten.]

    W. Rogers
     
  14. Carl Fogel

    Carl Fogel Guest

    "G.T." <[email protected]> wrote in message news:<[email protected]>...
    > jim beam wrote:
    > > Carl Fogel wrote:

    [snip exciting weight details]

    > >> [Carl scribbled:] Of course, this is all an excitingly
    > >> academic fuss that started when I quibbled with Jobst's
    > >> comment that rims weigh exactly the same after
    > >> anodizing.
    > >>
    > >> The chief thing that I noticed in the BikePro rim
    > >> section was their claim that the MA 2 was anodized and
    > >> then drilled and rolled:
    > >>
    > >> "The MA2 is a Box shaped extrusion, with the three
    > >> exterior surfaces, both side walls and the hub facing
    > >> side of the spoke bed wall high polished to a bright
    > >> Silver aluminum then Clear anodized to harden and
    > >> preserve the finish. The extrusion is then drilled for
    > >> the spoke and valve holes and rolled into its hoop
    > >> shape." from
    > >> http://www.bikepro.com/products/rims/mavicroad.html
    > >
    > > [Jim commented:] i may be wrong, but i doubt /any/ rim
    > > is hooped after anodizing. anodizing is too brittle and
    > > the bending will expose unprotected metal. completely
    > > defeats the point.
    > >
    > [Greg replied:] Anodizing defeats the point in the first
    > place. Do you really think manufacturers that promote
    > anodization would do it the right way?
    >
    > The extrusion is usually anodized first in a long tank.
    >
    > Greg

    Dear Greg,

    When I called a week or so ago, the Mavic people said nope,
    anodizing comes last.

    But I've been lied to before. I'm also willing to believe
    that different rim makers use different anodizing steps,
    even for different models of rims that they make (the
    BikePro page from 1997 obviously indicates--rightly or wrongly--
    that Mavic used two different approaches back then).

    Do you have any particular rim makers in mind who currently
    anodize straight extrusions first in a long tank and then
    roll them into rims?

    And are you talking about plain/clear anodizing or hard
    anodizing or both processes?

    Variety is the spice of life!

    Carl Fogel
     
  15. Dianne_1234

    Dianne_1234 Guest

    On Sat, 06 Mar 2004 17:52:11 GMT, "Matt O'Toole" <[email protected]>
    wrote:

    >For the third time, yes. Extrusion dies wear with use.
    >Early production is thinner in cross section and lighter,
    >later production fatter and heavier. This is why rim
    >weights vary, aside from things like the number of eyelets.
    >
    >Matt O.

    I meant that a single die may have multiple ports that
    produce several linear extrusions in one push. These multi-
    hole dies may have holes that produce variation in walls
    from one port to the next.
     
  16. Dianne_1234

    Dianne_1234 Guest

    On 6 Mar 2004 17:24:22 -0800, [email protected] (Carl Fogel)
    wrote:

    >But his tables show no drillings,

    Campagnolo's catalog several years ago listed weights, with
    the footnote that every spoke hole added 1.4 grams for rims
    with ferrules (or whatever word they used). IIRC, these were
    for rims with sockets and eyelets.

    So variation in rim weight (due to hole count) between 32
    and 36 hole rims might be on the order of 4 * 1.4 = 5.6
    grams, with the 36 hole rim weighing more than the 32
    hole rims.

    When was the last time you saw a 28 hole MA2? I suspect most
    rim weights are quoted for either 32 or 36 holes.
     
  17. Dianne_1234

    Dianne_1234 Guest

    On Sun, 07 Mar 2004 02:59:10 GMT, jim beam <[email protected]> wrote:

    >who knows what they regard as an acceptable standard
    >deviation.

    ... who knows if they even measure it, or care?

    > if they didn't quote a mean, they'd have to quote a range.
    ... or a minimum, or a single sample, or a made up
    number....
     
  18. Dianne_1234

    Dianne_1234 Guest

    On Sun, 07 Mar 2004 02:59:10 GMT, jim beam <[email protected]> wrote:

    >i may be wrong, but i doubt /any/ rim is hooped after
    >anodizing. anodizing is too brittle and the bending will
    >expose unprotected metal. completely defeats the point.

    At the Sun factory many years ago, I personally saw
    Levanther rim extrusions (straight) that were anodized a
    bronze color get coiled into hoops.

    I also saw Sun MA14 rims getting coiled before anodizing.

    So rims can be anodized before coiling, after coiling,
    never, etc.
     
  19. Jim Beam

    Jim Beam Guest

    from what i understand, for extruded meatals, you only have
    one port per extrusion because the microstructure of the
    "in" affects the microstructure of the "out". just like a
    striped toothpaste tube - if you had multiple outs, you'd
    have a real hard time making sure they all extruded the same
    stripes in the same way. and consistency of output is
    essential.

    dianne_1234 wrote:
    > On Sat, 06 Mar 2004 17:52:11 GMT, "Matt O'Toole"
    > <[email protected]> wrote:
    >
    >
    >>For the third time, yes. Extrusion dies wear with use.
    >>Early production is thinner in cross section and lighter,
    >>later production fatter and heavier. This is why rim
    >>weights vary, aside from things like the number of
    >>eyelets.
    >>
    >>Matt O.
    >
    >
    > I meant that a single die may have multiple ports that
    > produce several linear extrusions in one push. These multi-
    > hole dies may have holes that produce variation in walls
    > from one port to the next.
     
  20. Jim Beam

    Jim Beam Guest

    amazing! remind me not to buy a sun rim!

    dianne_1234 wrote:
    > On Sun, 07 Mar 2004 02:59:10 GMT, jim beam
    > <[email protected]> wrote:
    >
    >
    >>i may be wrong, but i doubt /any/ rim is hooped after
    >>anodizing. anodizing is too brittle and the bending will
    >>expose unprotected metal. completely defeats the point.
    >
    >
    > At the Sun factory many years ago, I personally saw
    > Levanther rim extrusions (straight) that were anodized a
    > bronze color get coiled into hoops.
    >
    > I also saw Sun MA14 rims getting coiled before anodizing.
    >
    > So rims can be anodized before coiling, after coiling,
    > never, etc.
     
Loading...
Loading...