I recently bought a new chain, freewheel and chainrings for my "vintage" bicycle from Nashbar (the bike is 18 years old with six-speed freewheel). The chain came with a "master link" that I was able to install with difficulty using my bare hands after a lot of pushing and muttering.

After the chain was installed, I realized it was a little too long (because of a new smaller chainring) so I decided to remove a link. I found it impossible to remove the master link. So, I took out my cheapie chain removal tool (almost as old as the bike) and was able to accomplish the task in about 1 minute.

Is there some trick to this "master link" thing that I'm missing?

I think the outer plates have to be squeezed together before it will undo; I sometimes have trouble with mine .

Didn't it come with instructions?

What brand of chain?

Its best to practice with the chain off the bike with a clean chain. You have to relieve tension on the chain, press the sidewalls together, then press the ends of the link together. You dont need pliers or any other tools to break a Sram masterlink.

It is a "Nashbar" branded chain (Item NS-CCH if anybody wants to check it out), so I don't know who the manufacturer really is. It came with no instructions, but the master link looks similar to the SRAM Powerlink that Nashbar sells. However, unlike the SRAM, one half has both pins and the other half has two holes...one round and one slotted.

Looking at the link, it appears you have to push the thing so that the pin in the slot moves to the larger part of the hole. In practice, I found that impossible.

That's the "ease of assembly" type link, not really meant to be taken on and off like the SRAM. Fact is, I usually just chuck the link and go with the chain puller as I usually have to shorten the chain. Just as easy.