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Building a bike from scratch sounded like a fun challenge, but a frame builder firmly told me to get the headset installed professionally. Videos online make it look easy even if you don't have the right tools, and while it'd be easier/safer/higher-quality/faster to have an LBS do it, there's always that sense of pride of doing it all yourself.

Is installing a headset without professional tools and guidance an unfixable disaster waiting to happen (e.g., sawing the steer tube too short or installing the star nut crooked)? Is it in a different league than bottom brackets and wheel building?

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    Just to note: I have giant clamps to install the cups, pipe to install the crown race, and washers to (somewhat) center the star-nut in the steer tube. It's not just me with a beer and a hammer.
    – Laoshi
    Apr 18 at 16:59
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    What's the potential cost of getting it wrong? Multiply that number by the probability you're going to get it wrong (be honest with yourself here). If that number is higher than you're willing to risk, hire a professional.
    – Paul H
    Apr 18 at 17:32
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    building a wheel requires significantly more skill (and patience) than fitting a headset. I will give you an answer in a minute.
    – JoeK
    Apr 18 at 18:40
  • Wheel building is on another level from headsets and bottom brackets which, it could be argued, are on near equal level in terms of skill level required.
    – Jeff
    Apr 19 at 2:41
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    @PaulH This would be great if you had the right numbers to plug in, but that's kind of my problem, I don't know what could go wrong. (JoeK's answer mentioned cracking a head tube - who knew?). From the answers/comments, It seems there isn't a whole lot that would be permanently damaged if someone wasn't forcing parts in, but yeah it may be too much of a risk. I was also unsure about having wonky steering from a bad install, which would add to the "cost".
    – Laoshi
    Apr 19 at 19:53

3 Answers 3

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The headset is a straightforward unit. Two cups are pushed into the frame with an interference fit and the crown race is smacked onto the top of the fork in a similar way.

In the past, when I have had to, I have performed a headset swap using some large lumps of wood and a mallet. Your setup is luxurious in its detail.

Some people will not approve, but this is my answer, and if you want to (or have to) fit your headset with what you have to hand, you should, while understanding there is a risk of damaging your equipment.

Provided each part is pressed on square, there is very little to go wrong. You do one cup at a time, and if it starts to go off line, knock it out, try to determine the problem and if you need to scuff off any imperfections with a file or adjust the setup of your "tooling" and start again. If you are totally cack-handed, you can crack the head tube, damage the cups or both. You would have to be trying very hard though, the parts have inherent material elasticity that allows you to feel a problem before it becomes a permanent deformation.

It is important that the frame has been reamed and faced properly, which is generally done by the factory to a good enough standard. If it's a framebuilder-constructed frame, they will have done this as a matter of course. If you made the frame yourself, get someone to do this for you because the tools are insanely expensive.

Cutting the fork is simple. Once the headset is fitted, put the fork in, put everything on complete like you want it, spacers, stem, etc., mark the line on the steerer tube, take the fork out again and either cut here to use a 3-5mm spacer above the stem or cut 2-3mm below this line if you are prepared to take a risk. Make sure you cut it square. It's helpful to use a pipe cutter to start the cut, then either finish with the hacksaw using the line as a guide or finish with the pipe cutter and spend some time filing the outside of the steerer tube to get it down to the right diameter to fit the stem (the pipe cutter creates a bulge as it cuts). Even if you use a fork steerer cutting guide, you can still get a cut on the squiff so the pipe cutter is a useful tool, and cheap.

Fitting the star nut is easy. Some top caps are designed with the star nut fitting in mind and have a special shape to the bottom of them: you just put the star nut up snug and knock it in by hitting the top cap with a rubber mallet until it bottoms out. Other top caps don't have this feature but there are ways to improvise, I'm sure you'll figure it out.

We obviously assume you are using a fork with a metal steerer tube, as you are using a star nut. Carbon steerers require significantly different prep for the cut and that's an answer for another question.

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    You can also use a powered saw to cut the steer tube. A radial saw or miter saw is easy to use - just block the tube in place for a square cut. A table saw is a bit harder - you'd need a sled or other sliding apparatus to keep the tube aligned as it slides past the blade. For a steel steer tube, use a metal-cutting blade meant for ferrous metals. For a carbon fiber steer tube, use a decent wood-cutting blade that you don't care if the carbon fiber dulls the blade - so don't use your $250 80-tooth 12" Forrest Woodworker II blade... Apr 18 at 22:03
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I'd once bought a naked new Italian steel frame that I intended to build up myself. There were three things that I had done by the shop that sold me the frame. That was mainly because I didn't want to buy the rather expensive tools for just a one-time use. These were: facing the BB shell and having the threads re-cut, facing the head-tube and the steerer and having the classic head-set pressed in and having the seat tube reamed and mated to the seatpost.

Today I would still proceed the same way. Some works are better done by professionals.

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  • +1 to this. I built up a bare frame about a year ago and made exactly the same choices about what to let the shop handle.
    – Adam Rice
    Apr 18 at 19:29
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If carried out carelessly, even changing a chain can cause bad damage to the frame.

Consider headset installation against other commonly carried mechanical tasks on a bicycle. Why does nobody (usually) warn against tightening a seatpost collar at home, but one usually suggests going to a mechanic to press the headset in?

  1. The more often you practice some operation, the better you get at it. It is even better if you have received some sort of a formal/practical training for it.

  2. Many people learn how to turn screws at some point of life. Righty-tighty, lefty-loosey, correctly sized wrenches and all that. We meet many screws in our daily life. Turning bolts on a bicycle generally does not stress anyone out.

  3. With press-fit interfaces, the situation is different. We do not meet them in daily life (i.e., we do not press stuff in/out all the time). People do not necessarily have intuition about what tools to use and why, what preparations to do, what measurements to make, how to control the process etc.

  4. Having right tools for the job is critical for increasing probability of success. For threaded interfaces, one is likely to already have a wrench, hex key or similar at home. Press-fit tools are less universal as they do not serve multiple purposes and are not used in daily life.

Now, compare a professional bike mechanic vs an amateur. The former person has dealt with pressfit installation before, has likely received some training on it, and has access to right tools. The latter person performs it maybe once in a lifetime (or once per bicycle he/she owns), has only seen instructional Youtube videos, and has to buy expensive specialist tools for the job, or struggle with DIY substitutions.


In the end, it is your call, and nobody can make it for you. The risk/reward here is a personal choice.

My personal story: I have pressed in/out about three headsets at home so far. Until I had acquired all the required specialist tools, it was a pain to do. Even with the tools, I had to undo and redo installation of a pair of (angleset) cups. For a fourth headset of the IS type, nothing had to be pressed in at all.

All these bikes turned out fine (so far). I have never sawed a steering tube too short. Same story with the starnuts, although it is always scary to see them go in at an angle initially. The headset cups are worse, and I would not try doing them without a tool and without measuring the interference fit. My worst experience is the crown race installation. If it is not one of a split kind, then putting it on without a proper tool is a nightmare.

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  • Good point about the pressing part. I was most worried about the star nut, but I'll pay extra attention to centering the cups.
    – Laoshi
    Apr 19 at 19:29
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    If you bodge the starnut installation, there is usually a second chance. Just push the first one deeper into the steering tube out of the way, and try again with a new one. By the way, I think you can ask a bicycle mechanic to do exactly this one operation, while completing other stuff (cutting, cups etc.) yourself. I know people who build their wheels at home, but come to a professional for the final step of tensioning and truing the resulting wheel. This way, it costs less in money as it takes less amount of professional labor time. Ask your bicycle shop if they are OK with that. Apr 20 at 7:40

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