My Tarn Ti came with a Prestine PT-1860 which is a fully integrated headset. It works fine once done up but annoyingly comes fully apart if you undo any the top cap and stem. Is this just a rubbish headset design or a ‘feature’ of fully integrated headsets? Alternatively does anyone know any tricks to keep it together like all my previous headsets would (king, hope etc) where you would need a rubber mallet to knock the steerer down after removing the stem.

I’m missing something. Why are you removing the stem?

I’m not. I’ve an oneup stem with the preloader built in. If the headset develops play you need to straighten bars then it needs to be detensioned. At that point the headset goes massively loose making assembly a pita (you have to align the bars prior to preload while trying to keep it sufficiently tight that the preloader can take the slack.

Yes Im considering throwing it away.

Ah, yes. If the headset is developing play through normal use, I’d be looking to fix that 😁

We talking cartridge bearings that drop directly into the headtube?

Stick a hope one in?

Are you tightening the stem bolts in two stages?

OneUp instructions says:

1) Install bar. Top bar clamp bolts tighten down to stem body with no gap. Bottom bar clamp bolts will have a gap. Torque bolts to 6Nm

2) Install top cap spacers and top cap by clicking into stem before installing on bike.

3) Install stem onto steerer, align and tighten top 2 steerer bolts (9Nm).

4) Preload headset bearings, tighten lower steerer bolt (3Nm)

5) Torque preload lock nut (3Nm)

In any case, it’s not a failing of the headset design – holding everything together without bolts isn’t part of its brief.

Headset has only developed play when it was probably not tight enough and has them worked itself looser.

Yes using correct procedure. Step 4 is the preload bolt not the stem to steerer bolts. The difficulty comes when trying to get bars straight and gap sufficiently small (the peload can only take so much slack) and do up the bolts. If the headset stayed together this would be easier as you would not be trying to hold in together and straight at the same time. I know the headset is not designed to stay that way in use but a lot of previous headsets I have used held themselves together, I think by the upper split ring being pushed into the upper bearing and not coming back out.

I’m probably doing a crap job of explaining. On this bike if you put the bike in the stand and removed the stem the forks would fall out straight away. On previous non integrated bikes when you do this the forks stay where they are. Maybe I should just try a different (hope or cane creek) headset. Just need to work out which bits it needs!

On this bike if you put the bike in the stand and removed the stem the forks would fall out straight away. On previous non integrated bikes when you do this the forks stay where they are. Maybe I should just try a different (hope or cane creek) headset. Just need to work out which bits it needs!

They stay in place because the top headset cover is a tight fit onto the fork and maybe in the headset you have it isn’t?
I don’t use a stand so when I take the stem off nothing happens to the fork but if I lift the bike up the fork will start to slide down under the weight of the wheel and fork.

Aye, on some designs that spit ring, once driven into the gap, will hold the weight of the forks. I’d never rely on that though and would always use a pedal strap or similar if I was removing the stem with the front wheel off the ground. I’ve seen forks fall out of a frame (without a wheel attached) and the subsequent damage.

FWIW I always rest the bike on the ground when straightening the bars. I just don’t think I can visualise “straight” otherwise 😂

Again, I’m not sure a new headset is the answer.

No I can’t do straight in the stand either. On this particular bike I have to do it with the front pushed into a wall as that is the only way I have found to keep it in the right place. Your probably right about it not being the headsets fault. With a star nut or taped steerer I don’t imagine the same issues would apply (current steerer not suitable for taping though the new pikes waiting to go on should be).

Good point on the cover @kerley, the hope ones do tend to be a snug fit.

Didn’t someone (Reverse maybe?) make what is basically a spacer which does up like stem so that you can mess around with your stem and top cap without losing the preload on your forks/headset?

Would that help with your problem?

Edit
Here it is.
Steerer clamp

On a good headset the compression ring and the top cover o-ring should keep everything together if you’re rearranging headset spacers for example, with wheels on the ground though.
I’m with you, sounds like your headset is bobbins, but I wouldn’t rely on a decent headset holding the fork without a stem when elevated in a stand.