Old cassette + new chain = skip, but only on granny?
 

Anybody else had this happen?


The old chain was pretty toasty (according to my Park chain gauge), so I was expecting issues. But this is a new one - it only skips in back when I'm on the small (26t) ring. Doesn't matter which cog. Mystifying.


SP
OC, OR

Chain too long?

Don't think so. Used the "big-big plus two links" method that's always worked before.

More possibilities (all wild ass guesses):
* RD's spring is tired.
* RD is slightly gummed up/dirty.
* RD indexing is more bias towards the outer ring.
* worn chain was more flexible than the new one.

Chain tension is highest in the smallest ring.

???

Search: "free body diagram."

Chain tension is highest about the same in the smallest ring, speed and grade being equal.

I'd look at things related to the chain alignment first.

Expecting issues- got issues. Not that mystifying.

It's because your cassette teeth and or granny are worn down. Put the old chain back on and replace all the worn drive parts at the same time and in the future be more vigilant about replacing worn chains. Or just ignore the issue, but the old cassette and granny will cause premature wear of the new chain. The unmatched wear issue usually manifests on the smaller cogs/rings.

I've once installed three chains on a Shimano 6500 cassette at 2,500 intervals. I was pretty meticulous about maintaining the chains and cassette. The fourth chain install started to skip at about 300 miles. I had to junk the newish chain and cassette at that point.

Now I use two chains to one cassette and haven't had any issues. I've heard of some people who replace cassette whenever they do a new chain.

Got any pictures of the granny ring? Sometimes the skip actually happens up front.

Update: swapped out the cassette, problem solved! Thanks for the input.

SP
OC, OR