I was having a nice ride home this evening when, something unusual happened.

Starting from a complete stop in my usual gear, there was an odd dull pop sound followed by a completely free forward spinning chain. I found that a heavier gear would crank and I quickly realized that whatever the problem may be, it was something I had not encountered before. So, I altered my route to include my LBS.

The shop owner shows me my rear cartridge, an entire gear (the number 5, on the right side shifter) was gone. Somehow I managed to crack the gear in two with a bash of my hoof.

The rear cartridge and chain were both replaced for the first time in mid august.

The owner then proceeds to tell me that this is because I am heavy (260 lbs), and that I should alternate gears more to preserve the cartridge.

He put a new cartridge in (my second replacement in a year, this time free of charge), and took down my bikes serial number to file some sort of claim with Giant. The other mechanic checked my chain and recommended that I invest in a more robust chain (he named a German company), and cited 20% longer life for something twice the price.... felt like an "up-sell" to me.

I'm hoping this is a fluke, but I think it could also be inferior parts used by the LBS.

The cartridge the bike (Escape 2) came with lasted approx 2000 miles of heavy bashing in all conditions.