Ceramic Bearing Systems and Marketing BS Systems

Discussion in 'Road Cycling' started by Mike Kruger, Dec 12, 2003.

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  1. Mike Kruger

    Mike Kruger Guest

    I'm no engineer, but I just read Lennard Zinn's column in Velonews this week, and my marketing BS
    detector is ringing. Engineers on the list are welcome to chime in, if what's below if defensible.

    Lennard himself says "I have no experience with (ceramic bearings), ...so I will defer to someone
    who knows a lot about them." This turns out to be Bill Vance, National Sales Manager, ZIPP Speed
    Weaponry. So here's Vance:

    "How much benefit is possible from adopting this new technology? According to reports from real
    world testing done by ZIPP sponsored Team CSC an average reduction in wattage of three to four
    percent under our standard bearing systems, already the tightest standard within the industry can
    be expected.

    "For an average trained cyclist developing 250 watts, that's a savings of approximately 10 watts. At
    any level of competition, that is significant. The key is every part of the bearing system has seen
    marked improvements in precision resulting an a total benefit greater than the sum of its parts.

    "Similar to current math theory, at some point numbers reach a point where the rules just don't hold
    true any more."

    Wow. I love the chutzpah of "at some point numbers reach a point where the rules just don't hold
    true any more."

    But, as I said, I'm no engineer. So, for all you engineers out there, can there possibly be that big
    a difference in total system efficiency in changing from high-quality steel bearing systems to
    anything else?

    Full column is at: http://www.velonews.com/tech/report/articles/5327.0.html

    --
    Mike Kruger I didn't believe in reincarnation last time, either.
     
    Tags:


  2. In article <[email protected]>, [email protected] says...
    > "Similar to current math theory, at some point numbers reach a point where the rules just don't
    > hold true any more."
    >
    > Wow. I love the chutzpah of "at some point numbers reach a point where the rules just don't hold
    > true any more."
    >
    > But, as I said, I'm no engineer. So, for all you engineers out there, can there possibly be that
    > big a difference in total system efficiency in changing from high-quality steel bearing systems to
    > anything else?
    >

    I'm an engineer, but unfortunately I am a computer engineer, so I can't speak to ceramic vs
    steel bearings.

    However, number always follow "the rules." Sometimes we learn that the rules we know about the
    physical world don't work at some level, like quantum mechanics. But I suspect that ceramic
    bearnings don't have this kind of significance.

    Now, if I pretend to be an M.E., I would expect that the difference in friction between cermic and
    stell is probably *measureable* with instruments. But I don't expect the difference in the ride is
    measureable. Is 10 watts really that significant, given all the other factors?
     
  3. Jobst Brandt

    Jobst Brandt Guest

    Mike Kruger writes:

    > I'm no engineer, but I just read Lennard Zinn's column in VeloNews this week, and my marketing BS
    > detector is ringing. Engineers on the list are welcome to chime in, if what's below if defensible.

    > Lennard himself says "I have no experience with (ceramic bearings), ...so I will defer to someone
    > who knows a lot about them." This turns out to be Bill Vance, National Sales Manager, ZIPP Speed
    > Weaponry. So here's Vance:

    > "How much benefit is possible from adopting this new technology? According to reports from real
    > world testing done by ZIPP sponsored Team CSC an average reduction in wattage of three to four
    > percent under our standard bearing systems, already the tightest standard within the industry can
    > be expected.

    > "For an average trained cyclist developing 250 watts, that's a savings of approximately 10
    > watts. At any level of competition, that is significant. The key is every part of the bearing
    > system has seen marked improvements in precision resulting an a total benefit greater than the
    > sum of its parts.

    > "Similar to current math theory, at some point numbers reach a point where the rules just don't
    > hold true any more."

    > Wow. I love the chutzpah of "at some point numbers reach a point where the rules just don't hold
    > true any more."

    > But, as I said, I'm no engineer. So, for all you engineers out there, can there possibly be that
    > big a difference in total system efficiency in changing from high-quality steel bearing systems to
    > anything else?

    > Full column is at: http://www.velonews.com/tech/report/articles/5327.0.html

    Well you see in what language this is presented: "How much benefit is possible from adopting this
    new technology?" Not the use of "possible" not actual or otherwise. What is more important is that
    harder bearing balls do not mean the cones or inner races of bearings will last longer. Friction
    losses in bicycle ball bearings is so minute that this is not a reasonable way to spend more money.
    This goes along with all the other aerospace materials bicyclists are advised to buy. It falls into
    the titanium-carbon fiber-sintered metals-low spoke count" trend of the day. It may be good bragging
    fodder but it won't change performance of the bicycle or the checkbook.

    Jobst Brandt [email protected]
     
  4. Cheg

    Cheg Guest

    "Mike Kruger" <[email protected]> wrote in message
    news:[email protected]...
    > I'm no engineer, but I just read Lennard Zinn's column in Velonews
    this
    > week, and my marketing BS detector is ringing. Engineers on the
    list are
    > welcome to chime in, if what's below if defensible.
    >
    > Lennard himself says "I have no experience with (ceramic bearings),
    ...so I
    > will defer to someone who knows a lot about them." This turns out
    to be
    > Bill Vance, National Sales Manager, ZIPP Speed Weaponry. So here's
    Vance:
    >
    > "How much benefit is possible from adopting this new technology?
    According
    > to reports from real world testing done by ZIPP sponsored Team CSC
    an
    > average reduction in wattage of three to four percent under our
    standard
    > bearing systems, already the tightest standard within the industry
    can be
    > expected.
    >
    > "For an average trained cyclist developing 250 watts, that's a
    savings of
    > approximately 10 watts. At any level of competition, that is
    significant.
    > The key is every part of the bearing system has seen marked
    improvements in
    > precision resulting an a total benefit greater than the sum of its
    parts.
    >
    > "Similar to current math theory, at some point numbers reach a
    point where
    > the rules just don't hold true any more."
    >
    > Wow. I love the chutzpah of "at some point numbers reach a point
    where the
    > rules just don't hold true any more."
    >
    > But, as I said, I'm no engineer. So, for all you engineers out
    there, can
    > there possibly be that big a difference in total system efficiency
    in
    > changing from high-quality steel bearing systems to anything else?
    >
    >

    Some ceramic materials, like silicon nitride, are excellent bearing materials. They are harder,
    lighter, more thermally stable and more wear resistant than metalic bearings. For motor-driven
    bearings, wear resistance is usually a critical factor. Reducing energy consumption by 4% seems
    high, but ought to be easily verifiable by testing if true. The part about "the rules just don't
    hold true" is pure marketing hyperbole.

    OTOH, the Formula 1 cars are starting to use ceramic bearings and they are usually on the bleeding
    edge of technology where money is no object.. Here is some info, granted from another vendor: http://www.cerbec.saint-
    gobain.com/WhyCerbec/WhyCerbec.asp
     
  5. E. Willson

    E. Willson Guest

    Bearing friction in a bike is almost insignificant. A number like 10 watts sounds incredibly high. I
    think you are dealing with pure BS.

    Ernie

    Slartibartfast wrote:

    > In article <[email protected]>, [email protected] says...
    > > "Similar to current math theory, at some point numbers reach a point where the rules just don't
    > > hold true any more."
    > >
    > > Wow. I love the chutzpah of "at some point numbers reach a point where the rules just don't hold
    > > true any more."
    > >
    > > But, as I said, I'm no engineer. So, for all you engineers out there, can there possibly be that
    > > big a difference in total system efficiency in changing from high-quality steel bearing systems
    > > to anything else?
    > >
    >
    > I'm an engineer, but unfortunately I am a computer engineer, so I can't speak to ceramic vs steel
    > bearings.
    >
    > However, number always follow "the rules." Sometimes we learn that the rules we know about the
    > physical world don't work at some level, like quantum mechanics. But I suspect that ceramic
    > bearnings don't have this kind of significance.
    >
    > Now, if I pretend to be an M.E., I would expect that the difference in friction between cermic and
    > stell is probably *measureable* with instruments. But I don't expect the difference in the ride is
    > measureable. Is 10 watts really that significant, given all the other factors?
     
  6. In article <[email protected]>,
    Slartibartfast <[email protected]> wrote:

    > In article <[email protected]>, [email protected] says...
    > > "Similar to current math theory, at some point numbers reach a point where the rules just don't
    > > hold true any more."
    > >
    > > Wow. I love the chutzpah of "at some point numbers reach a point where the rules just don't hold
    > > true any more."
    > >
    > > But, as I said, I'm no engineer. So, for all you engineers out there, can there possibly be that
    > > big a difference in total system efficiency in changing from high-quality steel bearing systems
    > > to anything else?
    > >
    >
    > I'm an engineer, but unfortunately I am a computer engineer, so I can't speak to ceramic vs steel
    > bearings.
    >
    > However, number always follow "the rules." Sometimes we learn that the rules we know about the
    > physical world don't work at some level, like quantum mechanics. But I suspect that ceramic
    > bearnings don't have this kind of significance.
    >
    > Now, if I pretend to be an M.E., I would expect that the difference in friction between cermic and
    > stell is probably *measureable* with instruments. But I don't expect the difference in the ride is
    > measureable. Is 10 watts really that significant, given all the other factors?

    10 watts in 250 is the quoted number, so it's a claimed 4% efficiency gain. That's noteworthy. For a
    seasoned pro, that would probably be far more noticeable than any other equipment change they could
    make, short of dramatic body-position aero gains or something.

    The number is so high, frankly, that it seemed questionable on that basis to me. But all credit to
    Zipp for actually putting up a (claimed) number in a meaningful format, rather than just their
    "matched bearings with epsilon runout" numbers.

    --
    Ryan Cousineau, [email protected] http://www.sfu.ca/~rcousine President, Fabrizio Mazzoleni Fan Club
     
  7. Mike Kruger <[email protected]> wrote:

    > [Zinn punted on the question and quoted Zipp: ] "For an average trained cyclist developing 250
    > watts, that's a savings of approximately 10 watts. At any level of competition, that is
    > significant. The key is every part of the bearing system has seen marked improvements in precision
    > resulting an a total benefit greater than the sum of its parts. ...

    > But, as I said, I'm no engineer. So, for all you engineers out there, can there possibly be that
    > big a difference in total system efficiency in changing from high-quality steel bearing systems to
    > anything else?

    No.

    This question would be more appropriate for rec.bicycles.tech than
    r.b.misc, so I'm crossposting it and setting followups there.

    I calculated that the power dissipated in two standard steel ball bearing hubs is about 0.33 watts
    for a 75 kg rider+bike traveling at 10 m/s. It's hard to see how an improved bearing could shave
    more than some percentage of that (10-20% ?), which verges on negligible, I'm sure the aerodynamics
    of your shoe straps are more important.

    Since I already wrote up the calculation, here it is:

    Typical coefficient of friction for a ball bearing is about mu=1.5e-3 (for example,
    http://www.ntnamerica.com/Engineering/PDFs/2200/frictemp.pdf) Power dissipated in one bearing is

    P1 = mu * (m/2) * g * V_bearing where m is mass of rider+bike V_bearing is linear speed the
    bearing rotates at. P_bearingloss = 2*P1 total power lost in two wheels V_bearing = V_bike * d/D d
    = bearing race diameter D = wheel diameter P_bearingloss = mu * mg * d/D * V_bike

    P_bearingloss = C_bearingloss * mg * V_bike where C_bearingloss = mu * d/D, can be compared to
    C_rolling resistance of tires

    For a bearing race diameter of 20 mm and wheel diameter of 668 mm (700x23) C_bearingloss = 4.5e-5
    for comparison, C_rolling resistance is supposed to be 4e-3 for smooth pavement (e.g. from
    www.analyticcycling.com), or 100x higher.

    For a rider+bike of 75 kg traveling at 10 m/s, the power dissipated in wheel bearings is 0.33 watts.
    A major technological breakthrough that cut bearing friction in half would only gain 0.16 watts. It
    might be significant in hour records or even the pursuit world record. At normal levels of
    competition, I think the sleep gained in not worrying about it has a greater performance benefit.
     
  8. David Kerber

    David Kerber Guest

    In article <[email protected]>, [email protected] says...
    > I'm no engineer, but I just read Lennard Zinn's column in Velonews this week, and my marketing BS
    > detector is ringing. Engineers on the list are welcome to chime in, if what's below if defensible.
    >
    > Lennard himself says "I have no experience with (ceramic bearings), ...so I will defer to someone
    > who knows a lot about them." This turns out to be Bill Vance, National Sales Manager, ZIPP Speed
    > Weaponry. So here's Vance:
    >
    > "How much benefit is possible from adopting this new technology? According to reports from real
    > world testing done by ZIPP sponsored Team CSC an average reduction in wattage of three to four
    > percent under our standard bearing systems, already the tightest standard within the industry can
    > be expected.
    >
    > "For an average trained cyclist developing 250 watts, that's a savings of approximately 10
    > watts. At any level of competition, that is significant. The key is every part of the bearing
    > system has seen marked improvements in precision resulting an a total benefit greater than the
    > sum of its parts.
    >
    > "Similar to current math theory, at some point numbers reach a point where the rules just don't
    > hold true any more."
    >
    > Wow. I love the chutzpah of "at some point numbers reach a point where the rules just don't hold
    > true any more."
    >
    > But, as I said, I'm no engineer. So, for all you engineers out there, can there possibly be that
    > big a difference in total system efficiency in changing from high-quality steel bearing systems to
    > anything else?

    I'm an electrical engineer rather than a mechanical, so it's not my area of expertise, but to me it
    sounds like what you say in the subject line.

    --
    Dave Kerber Fight spam: remove the ns_ from the return address before replying!

    REAL programmers write self-modifying code.
     
  9. On Sat, 13 Dec 2003 01:44:47 +0000, Mike Kruger wrote:

    > "How much benefit is possible from adopting this new technology? According to reports from real
    > world testing done by ZIPP sponsored Team CSC an average reduction in wattage of three to four
    > percent under our standard bearing systems,

    Very hard to believe.

    > "Similar to current math theory, at some point numbers reach a point where the rules just don't
    > hold true any more."

    Right. Now, I've only been studying math for 30 years, so maybe there is something I don't know.
    But, then again, maybe this is pure bullshit.

    --

    David L. Johnson

    __o | Accept risk. Accept responsibility. Put a lawyer out of _`\(,_ | business. (_)/ (_) |
     
  10. Just zis Guy

    Just zis Guy Guest

    That posting had me going for a minute - my server is called Slartibartfast and I was wondering how
    come it had added its name to a posting. What is it about engineers and Douglas Adams?

    Guy
    ===
    May contain traces of irony. Contents liable to settle after posting.
    http://chapmancentral.demon.co.uk
     
  11. Jobst Brandt

    Jobst Brandt Guest

    anonymous writes:

    > Some ceramic materials, like silicon nitride, are excellent bearing materials. They are harder,
    > lighter, more thermally stable and more wear resistant than metalic bearings. For motor-driven
    > bearings, wear resistance is usually a critical factor. Reducing energy consumption by 4% seems
    > high, but ought to be easily verifiable by testing if true. The part about "the rules just don't
    > hold true" is pure marketing hyperbole.

    Are you on the payroll with Zinn? This is so much double-talk and off subject it sounds like an Iraq
    war briefing. Bicycle bearing balls rarely fail or wear, the inner races (cones) failing most often.
    Harder balls can only make that condition worse. However, the subject was improved athletic
    performance not maintenance.

    > OTOH, the Formula 1 cars are starting to use ceramic bearings and they are usually on the bleeding
    > edge of technology where money is no object..

    > Here is some info, granted from another vendor:

    http://www.cerbec.saint-gobain.com/WhyCerbec/WhyCerbec.asp

    Great! and what does this have to do with to what Zinn alluded? If you don't have the answer to the
    question, just answer another question that no one asked.

    Jobst Brandt [email protected]
     
  12. Golightly F.

    Golightly F. Guest

  13. Di

    Di Guest

    Everything you read about ceramic bearings say they are harder and lighter than steel bearings, this
    alone would improve their performance, just how much could be debatable. It seems their big selling
    point is their ability to operate with less lubrication. By replacing the normal heavy weight
    bicycle bearing grease with a light oil, or in a racing environment, virtually no lube at all would
    make a big difference in performance. They are used in automotive turbo chargers, which is probably
    as harsh of an application there is, and I would assume they are used in jet engines also, but
    didn't find any data to support that.

    The average rider would most likely never notice the improved performance, but a racer should. If
    shaving one's legs makes a real performance difference then ceramic bearings would most likely feel
    like riding with a tailwind.

    "Mike Kruger" <[email protected]> wrote in message
    news:[email protected]...
    > I'm no engineer, but I just read Lennard Zinn's column in Velonews this week, and my marketing BS
    > detector is ringing. Engineers on the list are welcome to chime in, if what's below if defensible.
    >
    > Lennard himself says "I have no experience with (ceramic bearings), ...so
    I
    > will defer to someone who knows a lot about them." This turns out to be Bill Vance, National Sales
    > Manager, ZIPP Speed Weaponry. So here's Vance:
    >
    > "How much benefit is possible from adopting this new technology? According to reports from real
    > world testing done by ZIPP sponsored Team CSC an average reduction in wattage of three to four
    > percent under our standard bearing systems, already the tightest standard within the industry can
    > be expected.
    >
    > "For an average trained cyclist developing 250 watts, that's a savings of approximately 10 watts.
    > At any level of competition, that is significant. The key is every part of the bearing system has
    > seen marked improvements
    in
    > precision resulting an a total benefit greater than the sum of its parts.
    >
    > "Similar to current math theory, at some point numbers reach a point where the rules just don't
    > hold true any more."
    >
    > Wow. I love the chutzpah of "at some point numbers reach a point where the rules just don't hold
    > true any more."
    >
    > But, as I said, I'm no engineer. So, for all you engineers out there, can there possibly be that
    > big a difference in total system efficiency in changing from high-quality steel bearing systems to
    > anything else?
    >
    >
    >
    > Full column is at: http://www.velonews.com/tech/report/articles/5327.0.html
    >
    > --
    > Mike Kruger I didn't believe in reincarnation last time, either.
     
  14. Cheg

    Cheg Guest

    Sorry, I didn't mean to offend the topic police. I was trying to say something about what ceramic
    bearings ARE good for. Don't get your knickers in a twist.
     
  15. On Sat, 13 Dec 2003 19:04:52 +0000, di wrote:

    > Everything you read about ceramic bearings say they are harder and lighter than steel bearings,
    > this alone would improve their performance, just how much could be debatable.

    Quite.

    > It seems their big selling point is their ability to operate with less lubrication. By replacing
    > the normal heavy weight bicycle bearing grease with a light oil,

    Um, you do know that "heavy weight" does not refer to its mass, right?

    > or in a racing environment, virtually no lube at all would make a big difference in performance.

    No, it would make a miniscule difference in performance.

    >They are used in automotive turbo chargers, which is probably as harsh of an application there is,

    So? A bicycle wheel is not "as harsh of an application there is".

    > The average rider would most likely never notice the improved performance, but a racer should. If
    > shaving one's legs makes a real performance difference then ceramic bearings would most likely
    > feel like riding with a tailwind.

    Right. Yes, they are right up there together in terms of performance enhancement.

    --

    David L. Johnson

    __o | Enron's slogan: Respect, Communication, Integrity, and _`\(,_ | Excellence. (_)/ (_) |
     
  16. In article <[email protected]>, [email protected] says...
    > If shaving one's legs makes a real performance difference then ceramic bearings would most likely
    > feel like riding with a tailwind.
    >
    >

    *Does* that make a difference? I always thought it was just to help with road rash.
     
  17. Matt O'Toole

    Matt O'Toole Guest

    > In article <[email protected]>, [email protected] says...

    > > This turns out to be Bill Vance, National Sales Manager, ZIPP Speed Weaponry. So here's Vance:
    > >
    > > "How much benefit is possible from adopting this new technology? According to reports from real
    > > world testing done by ZIPP sponsored Team CSC an average reduction in wattage of three to four
    > > percent under our standard bearing systems, already the tightest standard within the industry
    > > can be expected.

    > > "For an average trained cyclist developing 250 watts, that's a savings of approximately 10
    > > watts. At any level of competition, that is significant.

    Total bearing drag with any bicycle bearing isn't even close to 3-4% of total drag to begin with.
    Any figure I've seen on bearing drag is miniscule -- way less than 1% of total drag. And 3-4% of
    nothing is -- nothing.

    > > The key is every part of the bearing system has seen marked improvements in precision resulting
    > > an a total benefit greater than the sum of its parts.

    The only thing worse than people spouting this crap is that other people see fit to publish it. As
    long as it makes a buck, I guess...

    Matt O.
     
  18. B.C. Cletta

    B.C. Cletta Guest

    > But, as I said, I'm no engineer. So, for all you engineers out there, can
    > there possibly be that big a difference in total system efficiency in
    > changing from high-quality steel bearing systems to anything else?
    > Full column is at:
    > http://www.velonews.com/tech/report/articles/5327.0.html

    "They are rated to a spin rate of 300,000 rpm versus a spin rate of 33,000 for our steel balls."
    300,000-rpm w/ a 700c wheel is 35,000-mph! (vs only 3800-mph @ 33,000-rpm.) you don't see an
    advantage in that?

    "The lubricant is also thermally stable and exhibits the same properties at -200 degrees as it does
    at over 2000." you can braze the frame w/o disassemble. you don't see an advantage in that?

    go forth and sin no more.
     
  19. John Everett

    John Everett Guest

    On Sat, 13 Dec 2003 01:44:47 GMT, "Mike Kruger"
    <[email protected]> wrote:

    >I'm no engineer, but I just read Lennard Zinn's column in Velonews this week, and my marketing BS
    >detector is ringing. Engineers on the list are welcome to chime in, if what's below if defensible.
    >
    >Lennard himself says "I have no experience with (ceramic bearings), ...so I will defer to someone
    >who knows a lot about them." This turns out to be Bill Vance, National Sales Manager, ZIPP Speed
    >Weaponry. So here's Vance:
    >
    >"How much benefit is possible from adopting this new technology? According to reports from real
    >world testing done by ZIPP sponsored Team CSC an average reduction in wattage of three to four
    >percent under our standard bearing systems, already the tightest standard within the industry can
    >be expected.
    >
    >"For an average trained cyclist developing 250 watts, that's a savings of approximately 10
    >watts. At any level of competition, that is significant. The key is every part of the bearing
    >system has seen marked improvements in precision resulting an a total benefit greater than the
    >sum of its parts.

    The fallacy of this assertion is so blatantly obvious I'm amazed it even reached print. So little of
    the 250 watts is consumed overcoming bearing friction that a reduction or three to four percent is
    reduced to barely perceptible background noise. Shame on Velonews for publishing this tripe.

    jeverett3<AT>earthlink<DOT>net http://home.earthlink.net/~jeverett3
     
  20. Frkrygow

    Frkrygow Guest

    di wrote:

    > If shaving one's legs makes a real performance difference then ceramic bearings would most likely
    > feel like riding with a tailwind.

    :) I love it!

    But then there's the equally important issue: "If" pigs could fly, what would ceramic bearings
    feel like?

    Oh wait, I know: exactly the same!

    --
    Frank Krygowski [To reply, omit what's between "at" and "cc"]
     
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