This is a longshot, but it's worth a try: Spokes rubbing against each other caused a similar problem for me--and it took me months to finally figure it out. To check: place a drop of chain lube at the point where the spokes cross over each other. If, when you ride, there is an elimination or dramatic reduction in the noise, then you've found your likely culprit.

If this is your problem, sometimes just putting a drop of lube every couple of weeks will solve it. Although ultimately I had to have my wheel rebuilt.

Or it might be something related. Follow these links for endless hours of fun: http://www.google.com/search?hl=en&f...earch&aq=f&oq=