Cup remover, headset press, hammer, and some grease
Before we start, a word about using the proper tools. This job is possible to accomplish without a proper cup remover tool and headset press, but we highly recommend using the correct tools. Using the wrong tool to remove your headset cups could result in a gouged headtube at best, or fatal damage to your frame at worst. Likewise, when pressing headset cups into your bike's headtube, having them go in crooked can have dire consequences. Using a proper headset press minimizes this risk. Take your time and use the correct tools, and if you don't feel that you're up for this job, take your bike to the local shop to have them do the work.
Step 1. Begin by sliding the cup removing tool into your head tube. You can remove either the top or bottom cut first
Step 2. Before you use the hammer, be sure that the edges are resting only on the inside lip of the cup and not any part of your frame
Step 3. With one hand over the opposite end of the headtube to keep the frame from moving, begin to hammer out the headset cup. Holding your hand over the cup will also keep it from flying out and giving you an embarrassing black eye
Step 4. Ease up as the cup starts to exit the headtube. Repeat the above process on the remaining cup
Step 5. Now it's time to install your new headset cups. Begin by checking the inside of the headtube for any damage from removing the old cups, and then greasing the inner surface to ease installation.
Step 6. Only install one cup at a time to minimize the chances of one going in crooked. Once the cup begins to enter the headtube, stop to make sure that it is perfectly straight. If so continue pressing it in, but if not you'll need to use your cup remover and try again.
Step 7. Once you've fully pressed the cup into the headtube, have a very close look to make sure that there is no gap between the outer edge of the headset cup and the face of the headtube. Repeat the process on the remaining cup and then follow your headsets directions to finish off the installation.
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