Originally Posted by
gsa103
Yes, time for new cassette. The middle of the cassette usually wears the fastest since you tend to ride more there and smaller cogs wear faster (fewer teeth to engage).
I've been running my commuter bike as a makeshift singlespeed (chain fixed on one cog in the existing cassette). Last night I installed a new rear derailleur and chain to convert to a 1x6 configuration. The cog I'd been using in the single speed setup is now skipping like crazy, but all others are fine. D'oh.