RE: [CR]


Example: Racing:Wayne Stetina



After working in the field of aircraft structures for twenty years I can tell you that predicting fatigue lives still is a bit of a black art! Big players are the maximum cyclic load level and the number of load cyclics over what is called the endurance limit. Other players include stress concentrations (nicks, sharp corners, etc.), corrosion effects, surface finish, etc. With steel, if the cyclic load is kept below the endurance limit, you will theoretically never have a fatigue failure. That explains why there are still so many thirty year old steel frames around. Of course big sprinters probably load frames above the endurance limit but unless you had the frame instrumented it is just a guess. Aluminum on the other hand, when subjected to cyclic loads does not have an endurance limit per se, but will eventually fail by fatigue. Think about that the next time you are flying in a thirty year old airplane! Actually, follow on testing takes this into account, but at some point aluminum airframes are retired.

Paul Raley I will take old steel ridden gently please, 50 deg and sunny in Leonardtown MD

ADP <aphillips9@mindspring.com> wrote:
>Giacomo brings up a really good point here for us neophytes (me too!) who
>are looking for a classic steel frame.
>
>Racers are tough.  Anything not steel, that has been raced hard on (by a
>big guy!) can be bent after just a season.  Had a customer come in with a
>carbon fiber bike that the rear wheel wouldn't even line up properly
>anymore.  She got it from a racer. My upstairs neighbor has got serious
>bottom bracket sway in his scandium Quattro.  Scott is a stocky, powerful,
>400+ mile a week guy.
>
>Steel is more resilient, but my SO - big ring grinder that he is (man with
>knees of steel!) has broken a few frames - broke (era content here) an
>early 80s Merckx seat tube near the bottom bracket, and did a job on a
>Paramount.
>
>So I know I can always get things aligned, and we can usually tell when
>something has been bent in a crash, but how much risk does one take when
>purchasing a classic lightweight that has been raced hard?  When do steel
>frames fatigue?  Or do they?
>
>I know I'm at less of a risk with my interest in smaller frames that fit,
>but something like a 56cm could be really beat!  How do you tell?
>
>I figure people like Dale, Brian and Richard, who actually get into things
>with torches can provide some insight here.
>
>Ann Phillips - Atlanta GA
>likes bicycles of drinking age!
>
>
>
>
>
>
>
>>Date: Wed, 5 Mar 2003 06:26:53 -0800 (PST)
>>From: "James \"Giacomo\" Bellora" <bellovelo@yahoo.com>
>>To: classicrendezvous@bikelist.org
>>Subject: [CR]Skinny Racers?
>>Message-ID: <20030305142653.42041.qmail@web21301.mail.yahoo.com>
>>Content-Type: text/plain; charset=us-ascii
>>MIME-Version: 1.0
>>Precedence: list
>>Message: 15
>>
>>Believe me boyz, not all racers are 5' 3" and weigh 135 lbs.  Just look at
>>the Belgium Classics riders who brave Flanders cobbled bergs or
>>Paris-Roubiax's Arenburg Forest.  Cipollini ain't not skinny
>>wanker.  George Hincapies is 6'1''.  Half the USPS team are 'tempo
>>monsters' who are -170-190 lbs and torque the crap out of their
>>frames.  Better yet, track riders are even bigger (esp. the match
>>sprinters).  Many of the pro race frames can certainly handle large
>>powerful riders--as long as you choose the right one and not the one with
>>the prettiest paintjob.  The Virginia/DC/MD area is mainly punch climbs
>>(rollers) and dead windy flats.  The majority of the dudes I race against
>>are definitely bigger than me (5'11"-160 lbs).  Not many Pantanis around
>>here.  The bicycle companies certainly have to design bikes (and wheels)
>>to handle the bigger dudes too.  This is why I race on a DeRosa Planet,
>>beefier than the tincan UD or Merak.
>>
>>
>>Giacomo Bellora, Falls Church, VA
>
>
>
>
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