Because of: 1. the economy and 2: a newer, lighter, more expensive bike won’t help me, I continue to do tris and time trials on my 1989 Klein Quantum. I had already replaced / upgraded everything on it, except the fork and headset. And, because I like the flexibility of unthreaded forks for different stems / angles / spacers, I decided to replace my threaded Klein steel fork with a 1" carbon fiber fork with aluminum steerer and FSA headset. As a side benefit, my Campy Chorus headset had pitted bearings that had to be replaced anyways. Note: This does not apply to a carbon steerer.
Here is what I did. Note: I have a bike stand. This job is a lot harder without one.
- Measure the current height of the top of the handlebar / base bar from the floor.
- Remove the current stem
- Unbolt the two headset nuts. There are special thin wrenches for this if you keep the old headset. If not, two pairs of channel lock pliers work fine.
- Unbolt the front caliper
- Remove the front wheel
- Remove the fork
- With a long punch (I used a 8" 1/2" diameter brass punch used by auto mechanics), punch the cups of the headset out by inserting the punch inside the head tube.
- Clean the inside of the head tube
- Install the new headset according to their directions. In my case, I tapped the new headset in with a rubber or plastic mallet. Do not use a steel hammer unless you tap on wood!
- Slide the fork into the headset and head tube
- Install the front wheel and lock
- Take bike off stand and place on ground
- Slide the new stem in place
- Slide the stem up and down so that the height where the handlebar contacts the stem, i.e., where the top of the handlebar would be, is the same height as in step 1. Lightly tighten the stem.
- Double check step 14.
- Triple check step 14.
- Mark the top of the stem. I used red.
- Recommended: Add 10 - 20mm of 1" spacers to provide flexibility later on.
- Mark the top of the spacer on the tube with a different marker. I used black.
- Tighten the stem, attach the handle bar / base bar, install the front caliper.
- Take the bike for a ride and see if you like the stem height.
- Put bike back on bike stand
- Remove handlebar / base bar
- Remove front caliper
- Remove front wheel.
- Loosen stem and remove. Hold onto tube so fork doesn’t fall out suddenly
- With a tubing cutter, cut tube 3mm below top mark (black)
- With a file or dremel tool, gently deburr the outside and inside of the tube.
- Clean metal filings out of tube.
- Install fork and hold in place
- Install front caliper
- Install front wheel
- Take bike off bike stand and put on floor
- Install a combination of spacers that you think will work to get the stem in place.
- Slide stem on
- If top of stem is below red mark, remove stem and add enough spacers so that top of stem is at red mark
Note: I prefer to use as few spacers as possible, mainly for aesthetics - Install star nut into top of tube. I used a small punch to keep it going in straight. This is a bit of a challenge. If you destroy the star nut, you can get a replacement at your LBS.
- Install spacers so that top of top spacer is 3 mm over top of tube. Top spacer must be 5mm or higher.
- Install cap and screw into star nut and tighten to headset torque spec. Note: The star nut just holds the stem in place until the stem is tightened and does not support any weight.
- Tighten stem to spec. I torqued stem to steering tube with 104 in-lbs and stem to handlebar with 87 in-lbs.
Done. Total time about 2 hours.