I’ve read recently that chain length is something that can be an issue if it’s either to large or small ?

Can someone explain why and what effect either would have on a bike and better still explain how exactly to tell the chain is the right length ?

Thanks

Put chain round largest chainring on front and largest cog on back. Pull it taught, and where the links meet, add one full link and chop there. If youre using a power link type thing, you’ll have to account for that.

If it’s too short you will not be able to get all the gears or will snap the chain or your mech.

If it’s too long it will flop about.

http://www.pinkbike.com/news/Tech-Tuesday-Chain-Length-Basics-2012.html
(put much better)

An explanation of the big to big combination and add 2 links

How to replace a Chain and find the Correct Length