Question about Shimano Cn-Hg701

It seems to me that you've never changed a chain yourself.

Let me recommend another video. In my opinion, he explains it best for laymen and is a likeable guy:

https://www.youtube.com/watch

Important: If the chain is already too long, it will have worn out the chainrings and sprockets. Then it won't be fun with the new chain. A chain gauge is therefore a must-have. You can say that a new chain needs to be fitted every 2000 kilometres. This prevents the lengthened chain from grinding out the sprockets/chainrings too much. If you miss this point, it's better to stay on the old chain and ride down the sprockets/chainrings. If the chain starts to jump over the sprockets, you'll have to replace everything. Then it can be dangerous.

Addendum: If in doubt, simply buy the longer one. Shortening is always possible. In most cases, you will have to shorten the chain by a few links anyway.

Counting the links of the previous chain is the easiest way. Otherwise, there are formulae for calculating the correct chain length.

https://fahrrad-rechner.de/kettenlaen...