I know a couple of you on here ride Cypresses, and I happened to run across this when I was researching Giants. Apparently the rear axle was made a little too hard and can crack. Here's the link, Giant will replace the rear axle and your rear tire for free for you if you have a defective one. They list the serial numbers that have this problem and the info about it here:


The Giant Rainier 2004 MTB has a recall on it as well.