Originally Posted by
rsbob
This just started occurring. There is no jarring and it doesn’t happen when shifting to a new gear, but occasionally, it seems like the chain is missing a tooth with a resulting clunk. Happens only occasionally. Front derailleur adjustment needed?
Could be a slightly bent tooth on a chainring, or a stiff or bent chain link, or indeed a combination of these that only occasionally aligns. I'd check those first, although if it's slight it may not be obvious.