Re: [CR] Phil disk brake, Vitus 172


Example: Racing

In-Reply-To: <7140CF56B91B4D42B329B086C3D67324@ownerd556865ac>
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Date: Tue, 6 Jul 2010 13:30:30 -0500
From: Harry Travis <travis.harry@gmail.com>
To: paccoastcycles <paccoastcycles@sbcglobal.net>
Cc: JB Froke <jbfroke@mac.com>, hmsachs@verizon.net, classicrendezvous@bikelist.org
Subject: Re: [CR] Phil disk brake, Vitus 172


Replies so far are consistent with everything I understand. I'd also think that some saddles would soften more in the course of a season.

Pursuing one branch of this notion or belief: As frames and forks go out of alignment, and the curved fork has been mandrel-bent so it visibly bends further in response to road shock, might there be anything to changes in instantaneous bending resistance of the fork blades after much use?

Harry Travis Pine Barrens of NJ USA

On Mon, Jul 5, 2010 at 10:51 PM, paccoastcycles < paccoastcycles@sbcglobal.net> wrote:
> I always saw it as two camps as regards frames "fatiguing". The camp who
> thought that frames didn't fatigue and those who were wrong. I'll have to
> say that there was quite a bit of passion on the part of those who insisted
> frames "got tired". Instead, I thought it was the riders who got tired of a
> given frame. Better to know the truth and just admit that you want a new
> frame. A new paint job will make a bike ride like new again. Oh, the wives
> tales!
>
> I owe a fair amount of my skepticism on this subject to Harry Phinney who
> worked at my shop many years ago. I learned some from everybody who worked
> there. Harry has a degree in metallurgy. I was priveliged to have his input.
>
> Chuck Hoefer
> Pacific Coast Cycles
> Oceanside, Calif.
> ----- Original Message ----- From: "Jim Merz" <jameshmerz@gmail.com>
> To: "Harry Travis" <travis.harry@gmail.com>
> Cc: "JB Froke" <jbfroke@mac.com>; <hmsachs@verizon.net>; <
> classicrendezvous@bikelist.org>
> Sent: Monday, July 05, 2010 8:06 PM
> Subject: Re: [CR] Phil disk brake, Vitus 172
>
>
> Not sure what your point is here. I guess you are bringing up the question
>> of frame getting "soft" from use. I think you can put this into the
>> category
>> of old wife's tale. The stiffness of a steel tube is based on the outside
>> diameter and the wall thickness. Improving the tensile strength from
>> alloys
>> or heat treating does not change the stiffness, and putting the tube
>> through use does not detract from the stiffness either. The only things
>> that
>> would reduce the stiffness of a built frame is if it is cracked, or that
>> the
>> wall thickness is reduced from rust. The benefit from using a very high
>> tensile steel such as 753 is that a strong rider can flex it quite far
>> without yielding it. But it is not "stiffer" than a frame made with the
>> same
>> gauge and diameter of 531. It will also resist buckling much better from
>> hitting bumps and other impacts. Maybe the tale was started so pro's could
>> get a new bike every year!
>>
>> Jim Merz
>> Big Sur, CA
>>
>>
>>
>> On Mon, Jul 5, 2010 at 7:10 PM, Harry Travis <travis.harry@gmail.com>
>> wrote:
>>
>> Ted:
>>> Will I find in your or selected other CR listers' or other engineers'
>>> remarks more on the wear of steel frames? Re:The "soft" , but not in
>>> "softening"
>>>
>>> >From the Wikipedia Reynolds tube entry (put here just for newbies like
>>> me,)
>>>
>>> 653 - Was a mixed tubeset which combined tubings of different steels;
>>> made
>>> up of 753 stays with 653 main tubes and 531 forks [7]. Following feedback
>>> from Eddy Merckx that a pure 753 frame was too harsh for certain stages
>>> of
>>> the Tour de France, Reynolds produced a 653 tubeset which combined 753
>>> stays
>>> with 531 main tubes and forks[citation needed]. The 531 used was a
>>> thinner
>>> gauge than usual, produced specifically for use in the 653 set[citation
>>> needed]. Eddy and other riders were very pleased with the result, which
>>> combined a light, ultra-stiff and efficient transmission with a more
>>> forgiving and comfortable ride[citation needed].
>>>
>>> [7] Tony Oliver, "The Touring Bike"
>>>
>>>
>>> I know you are only reporting supposedly well-informed gossip. But, it is
>>> from teen agers and guys in their twenties, few of whom could not have
>>> wanted new gear and envied those favored with such.
>>>
>>> In the religious wars over frame materials I've just not seen the report
>>> you
>>> offer here, in passing. For that matter, and this is even on-topic, I
>>> asked
>>> on bike.rec.tech whether anyone would report having replaced AND DESTOYED
>>> a
>>> functional aluminum handlebar of many years use, just because it was old
>>> enough and used enough to be suspect of being near the end of its fatigue
>>> life, and nobody affirmed he had done so.
>>>
>>>
>>> Harry Travis
>>> Pine Barrens of NJ
>>> USA
>>>
>>>
>>> _______________________________________________
>>
>
>
>
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--
Harry Travis