In this article you’re going to learn how to install a freewheel cassette. The installation process is incredibly straightforward. Your rear wheel hub contains a threaded part on which you screw the entire freewheel cassette.
YouTube Tutorial
Remove freewheel cassette

Unlike newer freehub cassettes, freewheel has the rotating body integrated with the cassette. Though it’s not so difficult to install a freewheel cassette, removing the old one can be much more difficult. Learn more in the article on how to remove a freewheel cassette.
I use the Park Tool Freewheel Remover FR-1.3 tool and an adjustable wrench to remove it.
Overhaul bicycle hub

With the freewheel removed you have clear access to the bearings on the drive-side. So it’s also a good idea to check them for signs of damage and / or overhaul the entire bicycle hub if necessary. If your freewheel was stuck it’s a sure sign that corrosion might have happened and your bicycle hub has suffered as well.
In my case I replaced all the ball bearings in the rear wheel and could have done it for the front wheel as well. And the wheel was missing a bearing on both sides as it turned out (they need 9 per side).
Install a freewheel cassette

Before actually installing the freewheel make sure you’ve applied a copious amount of grease onto the threads. If you ever want to remove the freewheel you’ll be thankful for it since the grease will significantly simplify this process. Put it on both the threaded part of the hub and the inside of the freewheel cassette.

Screw on the cassette making sure you don’t cross-thread and ruin your bicycle hub. You can use the freewheel remover to tighten the freewheel cassette even further.
With that finished you’ve successfully installed a new freewheel cassette. If you like this article give it a thumbs up. If you have any questions or suggestions for new articles, let me know in the comments below. Cheers.