For a bike to function, it relies on four sets of bearings. Two are in the wheels. The third is the headset, which gives you steering, and the last is the bottom bracket, which allows the pedaling motion. Of all these, it’s the headset that’s easiest to maintain.
The headset sits inside the frame’s head tube, and cradles the steerer tube of the fork. This allows it to rotate when the rider performs a turn using the handlebars. Most modern bikes use a so-called “Aheadset” arrangement, where the handlebars are mounted on a straight stem that physically clamps itself onto the steerer tube. Older bikes used bent “quill” stems, which were inserted into the steerer tube and had an expanding wedge at the end to make the mechanical connection.
Why would you have to maintain a headset in the first place? Well, you’d want to keep your headset bearings running smooth so that your steering remains natural and linear, without any interference or grittiness. The lower headset bearing, in particular, is very susceptible to dirt and water ingress when riding in the rain or through wet ground conditions, especially if you ride a bike with no fenders.
Fortunately, with the right tools and supplies, servicing a headset is very easy. You’ll need the following.
- Hex keys or Allen wrenches, or maybe even Torx keys, to dismantle your stem
- Paper towels or a rag
- A headset remover tool and a headset bearing press, if your headset is the press-fit variety
- A torque wrench for putting everything back together
To go about it, first, remove your front wheel. If you run a front fender, remove it from the fork.
Loosen the top cap on the steerer tube all the way and remove it. Make a mental note of the spacers you run, and how they’re arranged.
Loosen the two opposing pinch bolts of the stem, then lift the entire stem, handlebars and all, off the steerer tube. Remove any remaining spacers that were under the stem, as well.
Once you get to the conical spacer that sits flush with the frame, make sure the fork is supported. Remove the conical headset top cover and the compression ring underneath it. Once the compression ring is loose, the fork is now free to fall out of the steerer tube.
Remove the fork from the bottom of the head tube. You may need a rubber or plastic mallet to gently tap on the steerer tube to help the fork out.
At this point you are now free to remove the top and bottom headset bearings. Depending on your type of headset, you can either remove these by hand (for an “integrated” headset), or you might have to tap them out (for a “press-fit” headset). Make a note of which bearing goes where.
For bikes that have a tapered steerer tube, the bottom headset bearing is larger in diameter; for straight steerers, the two bearings are the same diameter.
For integrated headsets, the bearings themselves are usually also chamfered (diagonally surfaced) such that they’re going to go in only one particular way – the chamfered side goes inside the head tube.
Check the condition of the headset bearings by trying to spin them with your fingers. If there is any grittiness or resistance, you’ll need to replace the bearings soon.
If the bearings still move freely, you’re good to go. The next step is to clean them by using a degreaser and a paper towel or rag. Wipe off as much of the old grease as possible. Do this too for the bearing seats on the head tube, the compression ring, and the steerer tube itself.
Take your grease and apply a fresh coat to all the surfaces you just degreased. A light coat is enough. Any excess grease will ooze out of the head tube once the parts are reinstalled.
Now reinstall all the parts, starting from the lower headset bearing. Then take the steerer tube, insert it through the head tube, and install the upper headset bearing. You may have to press these bearings into the head tube if your bike has a press-fit headset. For an integrated headset, just slide the bearings in.
Follow up with the compression ring. Once that is in, the fork can generally keep itself inside the frame without falling out. Slide on the conical headset top cover, then the spacers and the stem in the order you took them out. Don’t tighten any bolts at this point.
Reinstall your front wheel.
Now we adjust your headset pre-load. Reinstall the top cap. Turn the top cap bolt only until there is no more slack and the top cap is flush with the stem or spacers. After this, pre-load the headset by tightening the top cap bolt very slightly – only until it is snug. You don’t want to over-tighten this bolt because it will bind the headset bearings and result in bad steering.
To check your headset pre-load, put the bike on the floor. Apply the front brake with one hand, hold the headset top cover with the other, and rock the bike forwards and backwards. You want the top cap bolt tightened only just enough so that there is no knocking or play in the headset when you rock the bike. Once there is no knocking, you’re all set.
Finally, set your handlebars straight, and turn the stem pinch bolts in until they are snug. Take your torque wrench, set to the appropriate torque, and alternately tighten the bolts a little at a time until they’re properly torqued up.
Wipe off any excess grease. Reinstall any other accessories such as your front fender, and you’re done!