Today, for the second time, I broke a link in the chain of my Giant FCR-1 road bike. It's a decent-quality bike, two years old, with about 2000 miles on it. I weigh 160 pounds and am not a gonzo rider, so I'm at a bit of a loss as to why this has happened again. (I've ridden bikes for 30 years and never had a chain break before). The guy at the local shop who fixed it the first time (last summer) didn't have an explanation either. The chain runs smooth and quiet, and there's no obvious misalignment. Did Giant have a problem with quality control on their chains at some point? Should I spring for a new one, or just replace the link again and hope for the best?

Lee

just get another chain if you are worried. what was the mode of failure? side plate pulling away from the pin? plates breaking? was the chain properly connected(new pin, master link)?

Most common causes of chain failure

1) Improper installation
2) Improper reinstallation
3) Shifting under extreme load

Inspection of the chain will tell you which one it is.

Operator gave it to you straight. If you break a chain, it's usually either because the closure pin was closed badly leaving a link vulnerable to the side stress of shifting. Also if you shift under load the side stress is enough to overcome the peen on the rivets, allowing plates to move out to where they eventually fall off on one side, after which the chain will break the next time it's loaded.

Once you break a chain, simply repairing it without verifying the cause just sets up the next failure. At this point, given that it has 2,000 miles on it, I suggest you start fresh rather than risk a third break.

Consider getting a SRAM chain, they come with a master link to close the chain, no futzing around with installing pins with a chain tool.