How to install an external cup bike headset without a press:
To do this project at home you will need bike grease, a piece of wood or something similar, and a hammer. The reason for using a piece of wood is because it’s not going to damage your headset or your frame.
Ideally you would take this to a bike shop, but if you do choose to do it at home, be extra careful because you can damage your headset and possibly even your frame.
First step is to lube your headset and lube the inside of your bike with the grease. Then, carefully align the headset in the frame. Feel free to align the logo according to your preference.
Next, take your piece of wood and put it on top of your headset. For the first few taps on the headset make sure to go very slow, being sure that the headset is going in evenly. This is the most critical part so don’t rush it. Constantly walk around each side of the bike to make sure it is going in evenly.
Once you get your headset seated, you will see a lot of your bike grease shoot out of the sides. Wipe the grease off and make sure the headset is fully flush with the frame. Don’t be afraid to give it a couple extra taps just to be safe. Now, all you have to do is repeat the same process on the other side.