Does not sound right. Make sure you have a good set of calipers to measure. If it's new a chain should last at least a few thousand Km.
You probably do NOT need to change your cassette unless it's really worn, most cassettes will last 3-4 chains. Going from 11-25 to 12-25 should not be a problem if you choose to get a new one.
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Originally Posted by
rjones28
Addiction is all about class.