Good people of Bike Forum,

I have a 1993 (?) Trek 820 "Antelope." It has a threaded headset. Recently it began to develop "indexed steering." I'm endeavoring to replace the headset, both to fix the problem and for my own education. But this whole process is making me feel like the Mr. Bean of bike mechanics.

1) I got a brand new Tange-Seiki 1" threaded headset with a 26.4mm fork crown race diameter. Try as I might, I could not get the crown race onto the fork. It would slide down to the larger-diameter "area of resistance" beyond which it refused to budge despite vigorous hammering with a fork crown race setter. Giving up,

2) I put this headset back in the box and got an identical headset with a 27mm fork crown race diameter. This was still tough to get on, but I did it. However;

3) With both headsets, I have three problems:

3a) The fork's steerer tube is taller than the stack height of the headsets. Screwing on the lock nut all the way causes the its built-in plastic "seal" to get pushed out by the steerer tube, and leaves the top of the steerer tube exposed.

3b) Although the bearing cups look like they're the same size as the old ones, when the headset is fully assembled, the bearings in the lower cup are not completely concealed by the cup. This could be OK, but it smells funny.

3c) More serious than the above, I have major "play" in the headset. By that I mean when I engage the front brake and push the bike forward/backward, there is a major, major wobble. The bike is unrideable. It doesn't matter how hard I tighten the headset. Even if I tighten it to the point that the handlebar will barely even turn, I can't reduce the play.

To sum up: 3a leads me to believe I need a different headset with a larger stack height. 3c leads me to believe I'm using the wrong "size" headset. Is it possible that I'm trying to install the wrong kind of headset? I guess I just assumed that the bike requires a 1" because it's the most common, and I thought that a 1" threaded headset is a 1" threaded headset.

I still have headset #2 installed. I'm going to dig #1 out of the box and compare each piece to the original. But I need to do a little bit of this first:

Ignoring the lock nut, are you able to turn the upper race onto the fork past the point of no play to the point where it actually starts binding up?

For issue 3c,are you positive you have the bearings facing the correct way?

No. There's 1" JIS (japan industry standard) and another one. Sheldon Brown has more to say:https://www.sheldonbrown.com/gloss_i-k.html#jis

Nope, I can't get past the point of no play. It binds up way before that.

I have a feeling BikeMech's barking up the correct tree vis a vis problem 3c.

For problem 3a, I'd try getting one or two thin spacers so that the steerer tube doesn't push out the plastic ring in the top nut, might even need a 5mm spacer. Check with the LBS. Hopefully you didn't chew up the threads by putting the top nut on too far.
https://www.niagaracycle.com/product_...ducts_id=11171

BikeMech, you nailed it. I was following the instructions to the letter. Unfortunately... the damn instructions were wrong!

Here is the CORRECT diagram for anyone else in this situation:

headset..jpeg

After flipping the bearings over, all is well.