Re: [CR]More on ceramic bearings (long quote)


Date: Sat, 04 Aug 2007 14:59:27 -0700
From: Steve Maas <bikestuff@nonlintec.com>
To: classicrendezvous@bikelist.org
Subject: Re: [CR]More on ceramic bearings (long quote)
References: <99C49155-BC57-4B0A-92BC-8D2B0FB0F099@earthlink.net>
In-Reply-To: <99C49155-BC57-4B0A-92BC-8D2B0FB0F099@earthlink.net>


My immediate reaction to this quote from Zipp's sales guy was that it's fatuous on its face. No way could a ball bearing dissipate 10 watts, let alone could ceramic bearings SAVE 10 watts. This would be enough to cause significant heating of the hub.

So, a quick, back-of-the-envelope calculation. For a hub to dissipate 10 watts at a speed of 30 MPH, you'd have about 4 Kg of resistance at the bearing. If this were true, you couldn't take a hub in your hand and spin the axle with your fingers.

The use of ceramic bearings in bikes is a perfect example of the way that the bicycle industry has been groping for apparent improvements that really have no functional value. Sells bikes to cool twenty-somethings with bad educations, wide eyes, and high credit-card limits, though, and that's the cynical goal.

Steve Maas (sinking, again, into bad-tempered-old-man mode in) Long Beach California

Richard Risemberg wrote:
> This from ZIPP, who makes (very expensive) ceramic bearing wheelsets.
> Very interesting, and little of the blatant sales pitch in it.
>
>>
>
>> .........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.......
>
>
>> Bill Vance
>> National Sales Manager and Factory Guy
>> ZIPP Speed Weaponry
>
> http://www.velonews.com/tech/report/articles/5327.0.html (Near middle of
> page)
> --
> Richard Risemberg
> http://www.bicyclefixation.com
> http://www.newcolonist.com
> http://www.rickrise.com