Can never keep my headset tight

definitely using enough spacers so the star nut can do its job?

as you've got a torque wrench, have you checked the bolts after your ride? maybe they are working loose.

Is it a carbon steerer?
I ended up fitting an extra long expander bung in one of my forks.

If I get the LBS to face the headtube and fit a better lower cup (currently has a cheap Nukeproof in there), what are the chances of that sorting it?

Slim as regards the facing, nil regards the cup.

As above, it's the star nut doing it's job properly? What steerer material, prep paste etc. What stem?

Definitely enough spacers: I leave my rides with the headset nicely tensioned, then often after one bumpy descent I immediately notice a bit of play.

Currently an aluminium steerer, although I think I was having the same problem with a steel steerer on this bike (same headset).

I did get a new stem recently -- a Syntace Flat Force, which has a low stack height, and relatively high torque requirement (8Nm). But again, I think I had this problem before, with my Funnduro stem

I clean it down with ~97% alcohol before installing, but don't use cabon paste or anything. I do have some, so could try that if there's a chance it will help.

Slim as regards the facing, nil regards the cup.

Good to know, that'll save me some money if so.

The only other thing I realise now could be that my headset cup isn't properly installed. But I did use a headset press and it does look perfect (and again, I've had this problem on and off for years, with all sorts of frames, most of which had a headset installed already)

Are you using a star nut, or some kind of contraption for your headtube pre-load?

I find some of the pre-load ones would work loose (I know in theory they don't hold any load once the stem is tightened up...)

What headset are you using? I had this on my bikes, and it was especially bad on my gravel bike which gets real hammer.

I was running (variously) the Acros and FSA headsets that came with the bikes. Sort of mid-level, £30-40 headsets. Tightening up every ride. It all stopped when I blew £100 each on Cane Creek Hellbender 70 headsets for them. It's probably just a rubbish headset you've got.

Assuming the headset parts are all installed correctly, I’ve seen it in the past where a washer or something is missing and so when tightened it’s not properly compressing against the wedge spacer that fits between steerer tube and top bearing. If it’s all good then apply some grease to the underside of the bolt head (the interface between the bolt and top cap). I’ve had headsets in the past where they’d develop a bit of play after a few rides and this has always worked for me.

I can't remember if I have a star nut or compression plug in these forks, but like you say this shoudn't be what's holding things together once the stem clamp is tightened so I'm not sure that can be the problem

munrobiker that is what I've been wondering -- the current headset is a mix of what I had laying around; a decent Cane Creek top half with a cheap Nukeproof Neutron bottom

muggomagic, I'm pretty sure it's all in their properly, but I will check

ayjaydoubleyou: that's a good point actually. I hadn't thought of checking the bolts after riding, and when I last retightened it I think they did actually feel a bit loose. I'll check again, as that could at least tell me if the stem is slipping even when at the correct torque, or if the bolts are first loosening up

I should say, I do already run a spacer above the stem, so the stem clamp is fully overlapping the steerer

EDIT: am I an idiot, is there something really basic I don't know...? Do compression rings have to be installed at a 90deg angle? (and by the same logic, split crown races?)

You say you've had the problem for many years - always with this frame? The star nut or bung is irrelevant, that's just how you adjust it. I also run rigid forks, and the only time I've had recurring symptoms of what appeared to be the headset slacking off, it actually turned out to be the head tube had flared slightly so the cups were loose in the frame. Cheap second hand frame that I thought the headset cups had gone into suspiciously easily, so I was half expecting it. I bonded the cups in with epoxy and I'm still using it 3+ years later...

EDIT: I see in a later post the problem's occurred over multiple frames.

I had this on a BMX and it drove me nuts for a bit. The fix was: thoroughly cleaning the stem steerer bolts and threads and then regreasing them as it allowed better torque application to the steerer.

Well, I just stripped it down and I'm as certain as I can be that nothing is missing, backwards or upsidedown

The bolts still felt quite tight as well -- I couldn't check properly as my torque wrench is cheap and I'm not sure it measures backwards

I will grease the bolts and do them to 8Nm again. If no luck, carbon paste. If still no luck, new headset and face

montgomery: yes, on different frames, and this one was unused when I got it, so the headtube should be good

Are you sure the steerer isn't pulling out of the forks? I've never known it happen, but it doesn't mean it can't...
What forks are they?
A photo might help let us see the (potentially) bleedin' obvious...

A photo might help let us see the (potentially) bleedin’ obvious…

It's not like you could put the forks on upside down or anything...

Tension the headset up, then remove the top cap and top spacer and mark the head tube where the top of the stem is. After it comes lose, remove the top cap and spacer and review the mark, you should be able to tell if the stem is slipping or something else is causing the issue

I will grease the bolts and do them to 8Nm again. If no luck, carbon paste

Carbon paste first IME. Greasing bolts may lead to you over-torquing them if they're meant to be installed dry. 8Nm is a maximum, not a target 🙂

and I have a little problem solvers clamp substituting a headset spacer to add a little more clamping force

Is this what you are referring to?

I can’t remember if I have a star nut or compression plug in these forks

Are you suggesting you are using both the star nut / plug and the adjuster? The blurb suggests you use it instead of a star nut / compression plug so are you perhaps using both and having them interfering with each other? It looks like they are adjusted differently - the star nut is effectively pulling the stack together with the stem undone whilst that adjuster expands to fill the gap with the stem already done up.

With the adjuster are you definitely using it correctly? e.g. are you tightening the bolt after adjustment? Without doing that I'd not be surprised that the threads 'walk' over time.

I can only go off my experience of the same issue and also thought it was due to rigid forks.

My forks are carbon so had a carbon fork bung. Turned out it was crap and when I was tightening it, it would pull up slightly. Then when on the trails this tiny bit of play would become noticeable.

I replaced the bung with an extra long one with rough sides to stop movement. I also used carbon paste and then a torque wrench. So far it seems to have fixed it but tonight's job is replacing the bearings so it might start all over again.

If your steerer is metal, ditch the fork bung and use a star nut. Make sure your stem is decent and can clamp equally top and bottom. Use a torque wrench to get the right tightness.

Good luck.

frogstomp, no it's just a simple clamp I'm using, like below, so it really just adds a little stack and clamping force to the stem

timba, I think I'll go back and add the paste then, and mark the steerer like 5lab suggests

suburbanreuben, I doubt the steerer is pulling through, that would be concerning, I will check if I can. Atm the forks on there are just some cheap rigids of a Brave Cairn ebike. My Reba's will be going back on soon, so I'll be able to check if the problem is somehow these forks

frogstomp, no it’s just a simple clamp I’m using

Fair enough. I would still suggest ditching it (even if only temporarily) and seeing if the issue goes away when you're relying on just the star nut / bung - it's just adding unnecessary complexity to the system.

Are your crown race and/or compression ring the same angle as the bearings? They do vary 45° 36° etc so if they don’t tessellate they may wear in over time.
Failing that it must be to do with the preload. It’s not simply bottoming out is it? How much does the stem (or spacer) sit proud of the steerer ?

Can you see if any movement has occurred at the fork crown / steerer interface?

had the same problem on a long travel fork, it was the crappy Cane Creek plastic top cap. Replaced it with a metal one and the problem was solved, good luck

Is the headset actually coming loose? Can you see it coming apart, or are you feeling a wobble with the front brake pulled on?

You sure it's not the brake pads moving a bit in the caliper?

Edit: also the top cap should not be doing anything once the stem is done up properly, so that should never be an issue.

If it's a star nut how was it fitted? I.e. did you use the proper tool? Could be that the star nut is slightly at an angle.

I had this twice, once was the bing slipping, one was not enough space above the top one the steerer. The top cap had a lip on the inside that I hadn’t noticed.

Sounds like something isn't square so can 'rock' loose. I'd get my head tube faced and a new quality headset installed. If it's still happening then it could be the face of the fork where the crown race sits.

Threadlock on the stem bolts?

another +1 for the method of tensioning shouldn't make a difference, once tight and the stem bolts are done up properly, that should be holding everything together. You can then take the tensioning system off even and the stem should stay put (exception are the under stem systems, I used to have one that was an expanding wedge sort but it was shit and I got rid)

You mention

and again, I’ve had this problem on and off for years, with all sorts of frames, most of which had a headset installed already

which sounds really odd, but also points to the common element being the user and makes me wonder if there is some sort of obvious issue - but I can't for the life of me see what given the descriptions.

In a scientific way, of removing / changing things and seeing the effect. Have you got a mate who can install it for you and then see if the problem goes away, or pay a shop - explain why (they might have an idea). Eliminate you being an eejit as the cause 😉

Could you remove all spacers and run the stem on top of the upper cup (with a ton of spacers on top to tension it) and see if that makes it go away.

Even after a lifetime of fixing my own bikes, I no longer have any idea what diam a steerer is other than there are several 'standards' now - you don't have an odd standard and the stem isn't the right size.

Also like the idea of marking and measuring to see if the stem is moving up.

I realise all of the above even as I type them ah 'nah, can't be' but as Holmes used to say, once you've removed everything else, what remains, however unlikely, has to be the answer.

Could also be that the bearing cup is either slightly big or oval which allows the bearing to move slightly. This could have happened during manufacturer or when installing. Or even crappy tolerances in the bearings, steerer, bearing cups etc.

I can’t remember if I have a star nut or compression plug in these forks, but like you say this shoudn’t be what’s holding things together once the stem clamp is tightened so I’m not sure that can be the problem

You can't remember, but you're forever taking it apart and/or tightening it?

I had this recently with my gravel bike, issue was that the bung wasn't tight enough AND there just wasn't enough gap between the top cap and the first spacer.

Could the bearing be installed upside down or top in bottom / bottom in top?

Or a part of the headset missing, like an expansion wedge or spacer.

I'd just buy a new quality headset if it was me, sounds like something is in off. Just remember to not overtighten the stem cap on installation then take it for a quick spin, after take up the slack on the top cap bolt. This might need to be done again after your first ride.

I've had headset that used to loosen over time as well but I replaced it and it was all good.

Rigid MTB forks can put a lot of fore-aft load on the headset under hard braking and impacts and headset bearing seats are often at a 36 or 45 degree angle with some degree of slack around the edges, most often with integrated bearing headsets. The forces on the fork against these bearing seat angles seem to create an expanding / extension force on the system between crown race and stem clamp and in the end the stem moves up on the steerer a fraction.
A headlock to replace the star nut can help, expander bungs, carbon steerers and very light stems with cut-outs and less clamping force/friction don't help.

and again, I’ve had this problem on and off for years, with all sorts of frames, most of which had a headset installed already

which sounds really odd, but also points to the common element being the user and makes me wonder if there is some sort of obvious issue – but I can’t for the life of me see what given the descriptions.

theotherjohn, exactly, I realise here that one of the common elements is me and I do wonder if I'm missing something obvious. But then, I do seem to be covering almost everything mentioned above, with the exception that I normally buy relatively cheap headsets and have never had a frame faced -- but barely anyone seems to be mentioning the latter, which surprise me as I thought that may be the biggest thing I'm missing.

It's possible that whatever issue I have now is specific to this frame, fork, or headset, rather than something I've systematically been doing wrong in the past (i.e. the days before I had a torque wrench, or any rubbing alcohol). So, I think I will put my Reba's back on a little earlier than planned and see if that sorts it. If not, off to the LBS for a Hope.

Personally I'd be looking at a new headset as a starting point; bits from 2 headsets you had laying around has lots of potential from a rouge part to get in there. Once upon a time you used to be able to get a pretty decent Cane Creek or WTB headset for £30-£40, but I'd imagine that those days are gone.

On a less positive note, if you've been riding it loose down bumpy descents for a long time, there's the possibility that you've ovalized the headtube a bit, so the actual cups could be wobbling.

That clamp thing you have, as far as I know it doesn't add clamping force to the stem. I believe that the idea is that once you've tensioned the headset and tightened up the stem, you tighten the clamp, this holds the tension in the headset if you loosen off the stem's clamp bolts (to turn the bars for transport or to swap stems) meaning (in theory) that you don't need to re-tension the headset each time you move and reset the stem.

It'll need to be completely loose (unclamped) when you're tensioning the headset otherwise it'll stop the top cap pulling up the forks and you'll be running with the same tension however tightly you think you're tensioning!

Thanks PJ, yes, I do realise that the problem solvers thing isn't designed as some sort of headlock system -- just figured it must add a little more tension to the system. I bought a couple years ago precisely for this loosening headset problem, but I've no idea if it helped.

And yes, I treat it like an extra stem bolt, so do loosed it off when adding headset preload.

I think a new headset may be the solution. I doubt I've wrecked the frame, or at elast I hope I haven't. It doesn't loosen off a crazy amount -- I can just feel 1 or 2mm of movement in the upper headset bearing when I put my fingers on the headset.

I can just feel 1 or 2mm of movement in the upper headset bearing when I put my fingers on the headset.

It can be difficult to do this without turning the bars very slightly as you test, this can feel like movement. It's also easy to misinterpret calliper movement (or the pads moving slightly in the calliper). Try pushing the front wheel against a wall and 'rock' the bike into it using a pedal; this can isolate the headset.

I do wonder whether you've got a mismatched compression ring in there.

I'm close to certain that the play is in the headset. I'm placing my fingers over the gap between the headset cover and cup when I do the rocking test, so I can directly feel if there is play in the headset. This is how I test if it's preloaded, and it always feels totally play free after I've retensioned it. I will try the wall test to be sure.

As for the compression ring, I did check this last night. Again, I'm almost certain I have the right one in there -- the upper cup is a Cane Creek 40 and the compression ring is a distinctive blue (not sure I ever had another one the same colour to mix it up with).

On a less positive note, if you’ve been riding it loose down bumpy descents for a long time, there’s the possibility that you’ve ovalized the headtube a bit, so the actual cups could be wobbling.

I've also had this, and it took me ages to work out what the issue was - junked the frame.

Get a new one!
You don't sound like an eejit but get the shop to install it, just in case...

How about an 'obvious' answer - the Stem clamp-bolts aren't tight enough to stop the Stem from moving when you ride down a rough descent at speed?

I know you're tightening the Stem clamp-bolts to 8Nm (presumably that's marked on the Stem) BUT...

1) Cheap Torque Wrench may not be actually giving you 8Nm.
2) 8Nm is defined by the Stem manufacturer probably to ensure you don't strip the threads in the Stem, it may not be enough to hold the Stem when riding rigid forks down a rough descent at speed.

I never use a Torque Wrench for Stem bolts but I do run the risk of stripping the threads in the Stem. However I've never had a Stem slip and allow the headset to come loose either ;o)

I think this is the perfect opportunity to buy a new bike, it's the only way to be sure 😜

didnthurt, don't encorage me, I've already been looking at new frames after the mention of an ovalised headtube panicked me...

JAG, perhaps this is true, but they are already damn tight, and I think my current stem has ti bolts, so I need to be careful not to round the heads

I have bought a Hope lower cup off the bay anyway, and will get Woodrup to install it when it arrives and face the frame. And have them confirm to me that it's not ovalised, of course (fingers crossed)

Assuming the headset is fitted and not moving and its clamped up by the stem then its working loose because:
a) lack of pre-tension
b) something moves/worn bearings from above

If the frame is SLIGHLY ovalised then a bit of bearing retainer can help.

Pre-tension .. have you got shims above the bearings? and if not do you need them? Is the top cap able to give proper pre-load into the bearings?

Is there enough gap to take up slack/preload... if you set and remove the top cap is there still 1-2mm clearance?
Is everything properly settled... proper rock forwards and backwards weight on wheel
Are all your spacers flat... if they are slightly thinner or thicker and rotate that would loosen
I'd remove the problem solvers thing... its just complicating matters

Something moves ?
Is it internal .. are the bearings worn so pack down as its in use?

Your challenge here is because you changed stuff and it kept coming loose your chance of ovalizing or wearing bearings etc. is increased so you might be to some extent chasing moving goalposts?