It’s important that your headset cups — the steering bearing parts that fit in the frame — are tight and secure. Here’s how to press them properly into place.
If your steering doesn’t turn smoothly, your bike won’t handle right. For the two bearings that make up the headset to work right they have to be properly aligned. In some frames this is taken care of by bearing holders built into the head tube, but in many frames the whole headset is a separate component that fits in the head tube.
The headset cups fit tightly into the head tube, so tightly in fact that the outside of the cup is very slightly larger than the inside of the head tube. This is known as an interference fit, and is what makes sure the bearings don’t move in the head tube.
That means you need a lot of force to get the cups into place. That can be done by hammering the cups into place (protecting them with wooden blocks) but a far better way is to use a purpose-made headset press.
Our guide below shows you what we believe is the best method to fit a headset cups. We've included a list of the tools and materials that you will need to complete the job and in some cases where you can buy them. If there are others that you prefer then feel free to let everybody know in the comments.
Pressing headset cups into a frame is one of the jobs that many bike owners fret about. It's really quite simple to do, but it really does require the right tool for the job and that is a headset press, a simple screwing mechanism which ensures the cups remain properly aligned as you press them into the frame.
1 Grease the head tube Use a little grease to ensure a smooth, easy fit that won't damage the head tube, or the alloy headset cups. We're using a copper based anti-seize compound by Finish Line. It's ideal for ensuring there is less chance for corrosion, or cold welding with metal on metal parts.
2 Spread the grease around Prep the upper and lower ends of the head tube. Use a finger to wipe the compound round the edge. You're looking for about three quarters of an inch of the inside edge covered.
3 Fit the bottom race We will begin with the lower cup of the headset. Release the bottom plate from the press. Lower the press shaft through the head tube. Place the bearing on the bottom plate and slide both back on the shaft. The press tool will have a spring loaded lock which work with detents on the press shaft to take up excess shaft length. You can see the spring lock between my third and forth fingers. Once the headset cup is squarely presented to the head tube and the lower press plate is locked to the shaft you're ready to begin.
4 Turn the press handle to push in the cup The trick is to go slowly and keep an eye on the lower cup to ensure it's being pressed in evenly. It should be, because the weight and squarely applied force mean that force from the side is minimised. Keep turning the handle. It'll be quite stiff; this is quite normal and actually a good sign. If the cup isn't a tight fit it can come loose, leading to premature wear and damage to the head tube.
5 Keep going until you feel the handle reach its stop and the lower cup is fully home. Don't just assume it's in place though. Inspect the point at which the lower cup and head tube meet. There should be no gaps anywhere around the circumference of the union between both elements. If there it, then give the cup a final tweak to close it up.
6 Fit the second cup To get the top cup in, we've turned the frame upside down in the workstand to make the job easier. As with the lower cup, remove the lower press plate first. Lower the press shaft through the cup (on top and out of this shot now that you've turned the frame upside down), taking care to use a stepped bearing drift to locate the shaft and handle assembly squarely in the lower cup. Place the upper cup on the base plate (as shown here) and when everything is squarely presented you can begin to turn the winding handle and press the cup in.
7 Going in square Here we've stopped halfway and removed the tool to show how the cup should be going into the head tube: squarely and evenly. With this style of headset the lower cup has an external bearing, and the top cup (pictured here) fits inside the head tube, wth only the lip of the cup sitting on the edge of the head tube.
8 Fully home Once the top cup is fully pressed home, remove the press. Inspect the union between the top cup and the edge of the head tube. As before there should be none. You now just need to slide the crown race on the fork and drop the top cup bearing shield into position before fitting the fork.