From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Spoke broke
Date: 14 Jan 1999 18:31:44 GMT

Doug (who?) writes:

>>> Why reuse spokes??They cost only about $10 for straight gauge-

>> Can you say, "Throw-away Society"?  It is my personal philosophy to
>> reuse *anything* that can be (note; not to the point of sacrificing
>> safety), and spare the landfills.

> So do you drain the oil out of your car.., run it through a coffee
> filter and put it back in the car?  Most things have a useful life
> and once spokes have been used (and stressed thousands of times)
> their useful life is over.

Not so.  A good stainless spoke probably has a longer life than your
bicycling career.  I have a pair of wheels that is well over 200000
miles old having had many rim replacements.  Spokes are not stressed
to more than 1/3 their yield stress and therefore, do not fatigue age
with use.  The reason they break, is that they have residual locked
in high stresses either from manufacture or installation or both,
that leave them near their yield stress locally.

Once a set of spokes has been stress relieved and is working well, you
do yourself a great disservice by throwing them away when rebuilding
with a new rim because you must go through the weeding out of spokes
that will break due to peculiarities that leave them with residual
stress.  Even a crashed an folded wheel does not damage spokes if they
are not kinked because loads on wheels only reduce tension rather than
increase it.  The slight increases that occur when a wheel is bent
sideways are insignificant to the strength of the spoke.

All this is not the case for Rolf or similarly low spoke count wheels
where individual spokes are far more highly stressed.  You don't get
something for nothing.

Jobst Brandt      <jbrandt@hpl.hp.com>