Originally Posted by dwood

It is really a misnomer when someone says they 'stress relieve' a spoke. When you squeeze adjacent spokes together, or press on the rim, or any number of other ways to 'stress relieve' spokes, you are not changing the metallurgy of the spoke one iota. Stress relieving most metals involves heating them to an elevated temperature, allowing them to 'soak' at that temp for a specific length of time, and then letting them return to room temperature, usually slowly.

What is really happening with bicycle spokes it that they are trying to reach the shortest distance between the rim and hub. The end at the hub seats itself. The nipple seats itself in the rim. Any twist in the spoke [due to friction between the spoke and the nipple when it is tightened] is allowed to unwind itself by either the nipple turning in the hub or the spoke unscrewing itself from the nipple. Once this is done the spoke is stable.

A spoke normally tightened never reaches it plastic region.