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/