Don Whitehead
Here is some classic and fun stuff on frame breakage from Jobst Brandt, who
is never short on opinions, although most of them are educated:
http://yarchive.net/bike/frame_break.html
2009/3/6 john
> in a crash ? Or maybe some other mitigating circumstance...?? Yes if
> they both broke of course it would catastrophic.
> But both tubes breaking by just riding along ? I highly doubt. Well
> with carbon fiber who knows, it being a material that does like to fail with
> no ductility exhibited...
>
> but with steel or aluminum... No way. I would only believe if i heard
> some hard specifics and all circumstances surrounding the failure....
>
> On Fri, Mar 6, 2009 at 3:59 PM, Long, Steve wrote:
>
>> OMG, I hate to butt in here but I've seen bikes break in half (top tupe
>> and down tube) completely seperating the front from the back of the bike. I
>> just have a hard time seeing how that would not be catastophic. And yes,
>> when this happens, it can happen in the blink of an eye. I've seen it happen
>> in several material types as well, including aluminum, titanium and of
>> course carbon.
>>
>> ------------------------------
>> *From:* obra-bounces@list.obra.org [mailto:obra-bounces@list.obra.org] *On
>> Behalf Of *john
>> *Sent:* Friday, March 06, 2009 3:43 PM
>> *To:* obra@list.obra.org
>> *Subject:* Re: [OBRA Chat] things to do with an old frame?
>>
>> That's what i would do, and then just ride it. Unless that dent is like
>> more then say 3/8" to 1/2" deep, i have a hard time believing that it is
>> "unsafe" to ride. A top tube, experiences bending and axial compression
>> loads and some torsion. If it does "fail" it won't be catastrophic, rather
>> you'll notice increased localized buckling at the dent, or maybe a crack
>> forming (not as likely since the compression will help keep the crack from
>> forming or propagating..).
>> The good news is the dent is right there within eyesight, so easy to keep
>> an eye on. When you notice something bad happening, then make it yard
>> art. I am guessing you will have you own house, yard, and mortgage half
>> paid by the time that rolls around, and of course at least another half
>> dozen frames, bikes laying around.
>> Even if it does break clean through while riding it, the down tube will
>> hold together until you stop.
>>
>> You should post a picture so we all can make "reputable" comments about
>> it. :) great end of the week fun.
>>
>>
>>
>> 2009/3/6
>>
>>> Ask a disreputable shop if it is safe to ride it.
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: "chris robinson"
>>> To: obra@list.obra.org
>>> Sent: Thursday, March 5, 2009 7:27:48 PM GMT -08:00 US/Canada Pacific
>>> Subject: [OBRA Chat] things to do with an old frame?
>>>
>>> I have an aluminum road bike frame that a reputable shop has deemed
>>> unsafe to ride because of a dent in the top tube, so I can't sell it to
>>> anyone and I don't just want to throw it out...any ideas?
>>> _______________________________________________
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>>
>>
>> --
>> jms, pe pdx, or
>> http://bikeeng.blogspot.com/
>>
>>
>
>
> --
> jms, pe pdx, or
> http://bikeeng.blogspot.com/
>
>
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