Originally Posted by
Sixty Fiver
I have seen machine built wheels de-tension themselves as soon as the tyre was installed and inflated... it sounds like someone running their fingers across a harp as they all lose tension because of wind up in the spoke that was not relieved.
Pre-built wheels can be a good deal as the sum of the parts is often less than what you have to pay for them singly... but they need to be checked.
I hope you will permit me to correct a couple of misconceptions you exhibited in your post. First spoke unwinding is a serious problem, but it is not because it significantly loosens spokes. In most cases unwinding won't even be as much as a quarter turn, and that is hardly enough to noticeably loosen spokes. What it does is throw the wheel out of true. Still serious, but a different thing altogether.
Second, stress relieving spokes is a different process than releasing the windup in them. Both processes are important, but they are different. Stress relieving is done by squeezing pairs of partially tensioned spokes together to raise the micro areas of high stress above the yield point. Releasing spoke windup is done by compressing the rim in a fully tensioned wheel (in several steps around the rim) to temporarily loosen the spokes so they can unwind. When the rim is released, the spoke are pulled taut again. Then a final round of truing/tension adjustment and checking is required.
I mention this as it is important for novice wheel builders to keep these things straight. More information about it can be found by Googling "Sheldon Brown Jobst Brandt stress relieving"