Have a relatively new KMC X10sl chain I need to make a couple of links longer to accommodate a 40t one up cassette ring
Also have a couple of brand new shimano links I removed from another chain (10 speed XT) recently
Can I simply add the shimano links to the KMC chain with a missing link or will this cause all sorts of skipping and indexing issues?

I guess other option would be to swap the chains on my two bikes around and add the shimano links back into shimano chain but that would then mean running the slightly worn KMC chain on a brand new drivetrain (and it may not be long enough anyway)

Which would be the best of two evils?

No one?

I have some spare new KMC X9sl links if that’s any use.
(I don’t think it is though 🙂 )

Yeah thanks Steve
Your all kindness 😉

I can’t see an issue with trying them out mixed in. A few turns in the bike stand would soon show if there are going to major issues, and a short test ride after that just to make sure. What’s the worst that could happen?