I replaced my chain recently... probably less than 300 miles ago. Last ride, I thought my rear der was bouncing between 12 and 13, as it wasn't shifting right to begin with... but then I started paying attention and realized NO... in fact, the chain is skipping over the teeth on my 12 cog.
The cassette has maybe 1,000-1,200 miles. It is a Tiagra, but I didn't think the lower end cassettes were prone to wearing out too fast- I guess I would have thought the opposite, even. It's a 12-28
This is the second chain on this cassette
I have a 39/53 up front- I really don't spend much time in the 12 cog... even if the cassette was getting worn out, the 12 cog is about the last cog I would expect to blow out on me.
What am I missing?
Group is 6600, if it matters.