Headset constantly coming loose

Jterrier

This one has me stumped. The headset on my bike constantly comes loose. All components are ok and installed correctly.

What happens is, i correctly install the fork, preload the top cap (which takes more tightening than I would like, though the top cap is not hitting the steerer), and it is all solid. I torque up the stem, its all good. Then usually after the first ride, it is all loose again; sometimes i can make it come loose simply by doing the 'hold front brake and rock bike' test. At this point the top cap has magically become very loose, and the spacers can be moved around below the stem.

Its a full carbon fork, and the bearings are all good. My options are;

Replace the expander bung, as it may be that, even though i cant detect movement; have added carbon paste.
Make sure the stem isnt slipping up the steerer even though i am torquing it up (alloy stem onto carbon)
Add another shim underneath the conical spacer, as maybe the split washer thing underneath isnt being driven down far enough into the head tube+bearing to hold everything right

Another thing i note; no matter how hard i tighten the top cap during installation, the steering never binds tight, which i think is a bad sign. Tells me maybe things arent being compressed as they should.

Its a fiddly problem this. Anyone?

foggymike

The other thing to check is that the steerer isn't cracked which would stop the stem holding it tightly enough (as well as being very dangerous to ride). That would be a long shot though but worth checking for safety.

Matthewfalle

Even though you have a gap between the steerer top and the steerer it may need to be bigger about 5mm is good.

You can either chop down the steerer a bit more or if not possible just slip a 2mm or so spacer under the top cap: no need to put something huge under there because you already have part of a gap under the top cap.

cooldad

Or you are just not tightening the stem enough and it's moving. Try without the torque wrench.

graememacd

What make is the fork bung? I had this issue earlier in the year with an fsa bung, turns out the bottom fitment that pulls up and makes it expand was on the end of the thread. I tightened that then found the bung would expand properly

Jterrier

graememacd wrote:

What make is the fork bung? I had this issue earlier in the year with an fsa bung, turns out the bottom fitment that pulls up and makes it expand was on the end of the thread. I tightened that then found the bung would expand properly

I think its an fsa, as the top cap and spacers are all fsa. When i checked it, the part that you refer to had indeed dropped clear of the threads; i have rectified it now, but oddly i dont think thats the issue. I note that the expander isnt knurled so it may slip, and even a quarter of a mm would be enough to make the headset go loose i think.

Jterrier

Matthewfalle wrote:

Even though you have a gap between the steerer top and the steerer it may need to be bigger about 5mm is good.

You can either chop down the steerer a bit more or if not possible just slip a 2mm or so spacer under the top cap: no need to put something huge under there because you already have part of a gap under the top cap.

There is about 5mm of spacer under the top cap; I did that deliberately to remove that as a potential issue

Jterrier

cooldad wrote:

Or you are just not tightening the stem enough and it's moving. Try without the torque wrench.

I wonder if maybe there is residual grease on the steerer where the stem grips it, which i need to completely remove....?

webboo

On one of my bikes if I use the correct torque, the headset always comes loose. I just tighten it a bit more.

lesfirth

If you can adjust it initially to remove the play there is nothing wrong with the bung spacers or top cap. Your stem has to be moving on the steerer. As Cooldad says ,tighten it more.

I have never tried to tighten the top cap until the steering binds. That sounds like a real bad idea but with bearings in good condition I would not think it was possible.

foggymike

I don't think he meant to leave it like that, just that it didn't happen if he kept tightening. A sign of the bung not working.

lesfirth

I did not think he was going to leave it like that either,but it is still a bad idea.

Jterrier

foggymike wrote:

I don't think he meant to leave it like that, just that it didn't happen if he kept tightening. A sign of the bung not working.

Exactly; thats the.thing, you Should be able to overdo the top cap, so that the fork wont turn freely, from which point you can then work out how far to back it pff again.

You cant do that with my bike!

So, the bung is slipping or the stem is slipping, or both.

foggymike

Yep, definetly the bung and maybe the stem as well.

lesfirth

foggymike wrote:

Yep, definetly the bung and maybe the stem as well.

Nope!Once you have set the bearing preload to remove any play and tightened the stem bolts sufficiently to clamp the steerer you can remove the bung and throw it away.Some hill climbers saving a few a few grams do.
You guys are not getting your heads around the mechanics of how this headset system works.

sungod

^^^this

the topcap/bolt/bung set preload, but it's the stem holds things in place

barring something broken, or incorrectly installed, the problem is that the stem is slipping

remove stem, degrease clamping surfaces of stem and steerer, refit, set preload, clamp stem

fwiw i use 6Nm on stem bolts, but different stems may need different torque

foggymike

I understand perfectly well how a headset works thanks. The op said he could tighten the top cap and the the headset didn't bind so presumably the bung is sliding up the steerer otherwise it would. It's possible that when the stem is being tightened there is still a bit of play.

Many manufacturers like you to leave the bung in too, especially if it's a carbon steerer. It gives some extra support to the steerer tube in case of stem overtightening as may well happen here given some of the advice above. We used to remove them in the olden days to save some weight which seems comical now, along with drilling holes in everything

dennisn

Jterrier wrote:

This one has me stumped. The headset on my bike constantly comes loose. All components are ok and installed correctly.

, IF the above statement is true then your headset is not coming loose. Just after this statement you talked of doing the job yourself. Well, YOU did it WRONG.

veryslowtwitch

foggymike wrote:

The other thing to check is that the steerer isn't cracked which would stop the stem holding it tightly enough (as well as being very dangerous to ride). That would be a long shot though but worth checking for safety.

+1, highly recommend you check this. I have had this problem and it took two shop visits to work it out. steering was "interesting"

veronese68

Jterrier wrote:

Then usually after the first ride, it is all loose again; sometimes i can make it come loose simply by doing the 'hold front brake and rock bike' test. At this point the top cap has magically become very loose, and the spacers can be moved around below the stem.

This is almost certainly the stem slipping. The only other options are the steerer tube is stretching somehow, so check it for cracks, or the bearing cups are not fully seated.

Jterrier wrote:

Exactly; thats the.thing, you Should be able to overdo the top cap, so that the fork wont turn freely, from which point you can then work out how far to back it pff again.

You cant do that with my bike!

So, the bung is slipping or the stem is slipping, or both.

This is a different issue and is the bung not gripping tightly enough. Not a good idea to overtighten the top cap too much as you could damage the bearings.

svetty

Jterrier wrote:

Add another shim underneath the conical spacer, as maybe the split washer thing underneath isnt being driven down far enough into the head tube+bearing to hold everything right

Invariably this is the issue/solution in my experience.

Jterrier

dennisn wrote:

Jterrier wrote:

This one has me stumped. The headset on my bike constantly comes loose. All components are ok and installed correctly.

, IF the above statement is true then your headset is not coming loose. Just after this statement you talked of doing the job yourself. Well, YOU did it WRONG.

Guys like you are so funny. Idiot.

dennisn

Jterrier wrote:

dennisn wrote:

Jterrier wrote:

This one has me stumped. The headset on my bike constantly comes loose. All components are ok and installed correctly.

, IF the above statement is true then your headset is not coming loose. Just after this statement you talked of doing the job yourself. Well, YOU did it WRONG.

Guys like you are so funny. Idiot.

Well, if all parts are OK and installed correctly then it's all good. Right? Jterrier did one or the other of these two WRONG.

lesfirth

Jterrier wrote:

dennisn wrote:

Jterrier wrote:

This one has me stumped. The headset on my bike constantly comes loose. All components are ok and installed correctly.

, IF the above statement is true then your headset is not coming loose. Just after this statement you talked of doing the job yourself. Well, YOU did it WRONG.

Guys like you are so funny. Idiot.

I will not comment as to whether dennisn is an idiot or not but he does have a valid point.

Ben6899

It's just dennisn's way. He's on of the good guys, really...

dennisn

lesfirth wrote:

Jterrier wrote:

dennisn wrote:

Jterrier wrote:

This one has me stumped. The headset on my bike constantly comes loose. All components are ok and installed correctly.

, IF the above statement is true then your headset is not coming loose. Just after this statement you talked of doing the job yourself. Well, YOU did it WRONG.

Guys like you are so funny. Idiot.

I will not comment as to whether dennisn is an idiot or not but he does have a valid point.

If you follow bike radar forum much you'll see this all the time. "I just bought a new blah blah model blah 1000, did all the work myself, followed all the instructions perfectly, doesn't work, must be faulty parts." Not trying to brag but I've been around a while and I've met plenty of people who, even with the proper tools, let alone the wrong ones, just aren't capable of doing a mechanical or electrical job correctly. How many times on this forum have you heard someone advise another that "No, all you need to build a wheel is an old fork, a spoke wrench, and a good ear. All that fancy stuff is just fluff." Sure, you can BUILD one that way. Having any trust in it is another story. Nothing wrong with trying your hand at things but resign yourself to the fact that if YOU did it and it doesn't work, it's most likely your fault.

Jterrier

dennisn wrote:

lesfirth wrote:

Jterrier wrote:

dennisn wrote:

Jterrier wrote:

This one has me stumped. The headset on my bike constantly comes loose. All components are ok and installed correctly.

, IF the above statement is true then your headset is not coming loose. Just after this statement you talked of doing the job yourself. Well, YOU did it WRONG.

Guys like you are so funny. Idiot.

I will not comment as to whether dennisn is an idiot or not but he does have a valid point.

If you follow bike radar forum much you'll see this all the time. "I just bought a new blah blah model blah 1000, did all the work myself, followed all the instructions perfectly, doesn't work, must be faulty parts." Not trying to brag but I've been around a while and I've met plenty of people who, even with the proper tools, let alone the wrong ones, just aren't capable of doing a mechanical or electrical job correctly. How many times on this forum have you heard someone advise another that "No, all you need to build a wheel is an old fork, a spoke wrench, and a good ear. All that fancy stuff is just fluff." Sure, you can BUILD one that way. Having any trust in it is another story. Nothing wrong with trying your hand at things but resign yourself to the fact that if YOU did it and it doesn't work, it's most likely your fault.

You might be right, but you still come across as a right pedantic smartarse with nothing constructive to add. Some kind of weird forum troll. I came asking for help, and the best you could do is snipe at my words. I dont remember the part where you suggested constructively how i might fix my problem.

g00se

Had a similar issue with an FSA headset and top-cap - maybe your issue is similar? The underside of the topcap was slightly conical - so even with a spacer this 'cone' would touch the top of the steerer before preloading the bearings enough.

Just stick another (or bigger) spacer on top to test it.

dennisn

Jterrier wrote:

dennisn wrote:

lesfirth wrote:

Jterrier wrote:

dennisn wrote:

Jterrier wrote:

This one has me stumped. The headset on my bike constantly comes loose. All components are ok and installed correctly.

, IF the above statement is true then your headset is not coming loose. Just after this statement you talked of doing the job yourself. Well, YOU did it WRONG.

Guys like you are so funny. Idiot.

I will not comment as to whether dennisn is an idiot or not but he does have a valid point.

If you follow bike radar forum much you'll see this all the time. "I just bought a new blah blah model blah 1000, did all the work myself, followed all the instructions perfectly, doesn't work, must be faulty parts." Not trying to brag but I've been around a while and I've met plenty of people who, even with the proper tools, let alone the wrong ones, just aren't capable of doing a mechanical or electrical job correctly. How many times on this forum have you heard someone advise another that "No, all you need to build a wheel is an old fork, a spoke wrench, and a good ear. All that fancy stuff is just fluff." Sure, you can BUILD one that way. Having any trust in it is another story. Nothing wrong with trying your hand at things but resign yourself to the fact that if YOU did it and it doesn't work, it's most likely your fault.

You might be right, but you still come across as a right pedantic smartarse with nothing constructive to add. Some kind of weird forum troll. I came asking for help, and the best you could do is snipe at my words. I dont remember the part where you suggested constructively how i might fix my problem.

OK then. Please explain to me how I'm supposed to know what YOU did wrong? In essence I've told you how to fix the problem. Find out what you did wrong. Read the instructions again. Find a video on you-tube. Take it to the local shop. Ask a buddy to help you. Have someone who knows what they are doing show you. Headsets are pretty straight forward. Still, I'm across the big pond. My advice. Take it apart and put it back together on video. Post it.

lesfirth

g00se wrote:

Had a similar issue with an FSA headset and top-cap - maybe your issue is similar? The underside of the topcap was slightly conical - so even with a spacer this 'cone' would touch the top of the steerer before preloading the bearings enough.

Just stick another (or bigger) spacer on top to test it.

In the second paragraph of the opening post the OP says,"I torque up the stem, its all good".I assume this is correct and the OP is not talking rubbish.
Therefore there is no problem with spacers , the bung or the top cap.The top cap and the bung have done their job.
If he had a problem with the spacers,the bung or the top cap it would not be possible to adjust it and it could never be "all good".
This really is simple!

keezx

In 95% of all cases of loosening headsets, the bung not staying fixed is the cause.
The other 5% are "mechanics errors" , like lower race not being in place 100%, wrong model of bearings, steerer top too high, centering ring damaged or similar.
Not a shadow of rocket science...