Originally Posted by
Martian63
Newbie here again. I just had a new chain and cassette installed at my LBS. I just noticed when I had it on the stand that when in the small chain ring and the smallest cog the chain sags down and actually rest on the chain stay. I don't ride here so never noticed it riding. Could the LBS mechanic sized the chain too long? The new cassette is an 11-28. It replaced a 12-30. I don't know enough to know if that makes a difference. Thanks guys for sharing your knowledge.
Yes, the chain is too long. The chain should not have so much slack as to drag on the chain stay. There are numerous articles in this Forum and the Internet describing how to determine the correct chain length. Plus, I'd think twice about going back to that bike shop for service -- it doesn't get more basic than installing a chain properly.