I recently put a new O-ring chain on my bike. I thought I could just count the links and cut the chain the same as the old one. The one I replaced had 108 links but it was not an O-ring chain. I broke the new one down to 108 and put it on my bike and I was 3-4 links short.
So I figured out the hard way, just take the old one off, lay it on the work bench and place the new one beside it and match up the length.
It's really fun putting the links back on! :ugg:
The master link is no joy either, I had to use the chain breaker to press the plate on. I don't know how you'd do it with out the breaker??