Should amateurs install their own headsets?

Question

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?

Answer 1

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.

Answer 2

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.

Answer 3

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?

0. 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.

1. 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.

2. 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.

3. 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.

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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.

Answer 4

Beware, don't assume all bike shop mechanics know what they're doing. I saw a mechanic force my headset cups in completely wonky and that was using the proper parktool headset press. He didn't seem to care when I pointed it out, just said it'll be fine. Also I know of a shop that uses a vice and blocks of wood to push headsets in 🤦‍♂️.