"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:
Translation: "I'm not going to put my name to a load of horseshit this huge, so I'll let the guy who
wrote it take the heat."
> "How much benefit is possible from adopting this new technology?
Are we talking about bearings spinning in zero gravity and a perfect vacuum, or bikes?
> 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.
Ok, yes, maybe you could save 3 or 4 percent for bearing friction. And why is that so important to
racers? (read on...)
> "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.
LOL! This is ludicrous. If there is even 0.1 watt saved, I'd be very surprised. Those numbers are
off by several decimal orders of magnitude. (Unless they tested the bikes in a vacuum, using
frictionless tires on a frictionless road surface.)
Look, my ordinary Shimano Ultegra hubs (and lots of other premium hubs) spin so damned efficiently
that it's crazy. They use Phil grease and Shimano-grade steel bearings, and the bearing friction is
as near zero as makes any difference for the system. So, maybe ceramic bearings are 3 or 4 percent
more efficient than a premium grease-and-steel setup. Who cares? Bearing friction is already so low
for good-quality hubs that you could drop it out of your equations (for real-world cycling physics
at racing speeds) and hardly notice any error in the results. It's down in the insignificant range,
several digits out. This claim of saving 10 watts in "real world testing" is just marketing
********, pure and simple. They should submit a paper to the Journal of Irreproducible Results.
> "Similar to current math theory, at some point numbers reach a point where the rules just don't
> hold true any more."
ROTFLMAO!! Straight out of the Donald Rumsfeld Big Book of Bullshitting. Translation: "Don't try to
reproduce our results, because you can't."
> Wow. I love the chutzpah of "at some point numbers reach a point where the rules just don't hold
> true any more."
It's beyond chutzpah, and well into the realm of pure fantasy.
> 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?
You don't need to be a degreed engineer to see that this is a truckload of steaming dung.
My challenge to ZIPP: Show me the numbers, and the test procedures. Until then, file under
"Hype and B.S."
Rocketman
