Installed new forks last night and it all went pretty well (apart from popping a brake piston out and having to do a bleed). However, there is some play in the headset which I can’t get rid of.

It’s a CK one and the problem appears to be getting the collar which sits into the top bearing race to centre and seat properly. There’s an o-ring inside it which means it’s a pretty tight fit around the steerer tube so it doesn’t move too freely.

The top cap has been done up to the recommended torque, but there’s still a bit of a wobble.

Any suggestions/advice/obvious f**kwit errors?

SC

Are you sure you’ve cut the steerer short enough and straight? Try it with an extra spacer before you try anything else.

That’s good advice for a start.

Steerer is fine. It’s straight and it sits about 2mm below the top spacer so there is plenty of space to pull everything together.

It was cut to exactly the same length as the steerer on the old forks.

Can you repack the bearings on a CK ? Might be worth a go.

Bearings appeared to have all the original grease still in them – pretty clean too.

crown race on the right way up?

Yup.

Well, it went on the same way as it was before… inner flange upwards.

(“inner flange” hur hur!)

Is the daft plasticy split washer bit in place? (the chamfered split ring that sits with the spacers or stem on top depending on your sexual orientation) 🙂

There’s no plastic split ring…

I know the kind of thing you mean – FSA headsets have alu ones, to push into the space between the bearing and the steerer tube.

I’m pretty sure I didn’t see one when I took it apart…

(Off to CK website)

PDFs show no split ring – bearing cap has a chamfered edge to do the same job.

o-ring could be worn, ck recommend changing periodically
(just changed them on both my ck headsets).

It was cut to exactly the same length as the steerer on the old forks.

Unless the new headset has exactly the same stack height then that might not be as sure-fired as you imagine.

I imagine 2mm clearance would be enough but just for the hell of it whack on an extra spacer and see. Some top caps have bevelled edges / lips on the inside that can foul the steerer as you preload. Bit of a longshot I accept but at least it would rule out one possibility.

Is anything else loose that you’re mistaking for play in the headset? E.g. loose caliper bolt.

2mm spacer is probably not enough. It is suprising how much slack is taken up compressing the headset (after havin it apart it takes a bit of force to get everything seated again) to get the top race seated.

I’ve done this before and thought it was OK with a small amount of steerer showing, but could not stop the play in the headset. Add another 5mm spacer and ignore recomended torque. Just nip it up and try it. If it’s still loose then do it up a bit more (common sense is required here, don’t go pulling on a long allen key use a bit of delicacy).

I usually just tighten the bolt until it starts affecting the steering, then back it off half a turn.

If the cap has a chamfered edge to do the same job, it mustn’t be quite pressing down its load (quiet Im trying to type here). Are there some really thin spacers less than a quarter of a mm thickness in there? If so, try removing one or two.

A-ha!

Got it.

Cheeky Monkey’s advice is sound. Instead of using a star-nut, I bought a steerer plug thing which looks like it is well engineered – 3 knurled facets tighten within the tube and grip it, then you screw the top cap into the inner thread. However it has a 1mm lip which sits on top of the steerer tube and seemed to be fouling the underside of the top cap. I stuck an extra spacer on and it seemed to tighten more BUT all it was doing was pulling the plug out! On inspection the knurled surfaces have some copper slip on them and the inside of the steerer is very smooth so it obviously wasn’t gripping.

I’ll degrease it all tomorrow and try again (or whack a star nut in!)

Thanks guys – I’m pretty sure the problem is solved.

Sounds all sweet! Well done!

nice one