Headset play, should I try some grip paste?

doug5_10

Summary: Ribble R872, carbon steerer, ITM expander bung, Deda alloy stem and roughly 1500km on the clock so far.

Headset is coming loose after 30 - 40km with noticeable knocking over rough surfaces, and can feel play (pulling front brake while stationary and rocking)

*Note - I am preloading bearings correctly, tightening top cap before stem etc.*

Originally had a 5mm spacer above stem which though might not be giving enough room and the top cap may have been tightening against the bung. Changed this for a 10mm so that top cap and bung are definitely apart . . . and it has come loose again.

I don't have a torque wrench but stem bolts are as hand-tight as I dare (I've stripped stem bolts before!). I also tried tightening further when preloading the top cap but this just starts to pull up the bung. I can only think the the stem is slipping upwards slightly?

Not sure what else to try other than grip paste on the stem-steerer interface (and probably for the bung as well). Does this make any difference on Alu - Carbon, I thought it was mainly for carbon - carbon surfaces?

jgsi

Thin k about fresh bung perhaps
Clean the inside of the steerer with isopropyl... you dont want grease anywhere near.
Dont overtighten stem bolts - its NOT the answer.
Are the bearings seated properly?

Last resort... new forks alloy steerer - star nut

and some stems do not need any spacers above - yes its true

step83

Be tempted to look at that bung as well as said give it a clean an do the same on the inside of the fork steerer they often use a release agent (powder) which would cause the slip.

balthazar

I'd suspect the headset elements aren't seated fully. If any of the headset components use a wedged shim arrangement to ensure a tight fit around the steerer (many do), it can be difficult to properly determine bearing preload. if you have any doubt here, try tapping the (loosened) stem down with a rubber hammer until you're absolutely sure everything is fully seated. The preload applied by a (possibly not tightly fitting) rubber bung may not be enough to overcome the stiction in these components.

Unfortunately this kind of thing is often best advantaged by a good sense of "feel" which comes only from experience. The dull thud when a bearing race is fully home is easily recognised by fitters, but difficult to describe. Whichever, it's unlikely to be a loose stem, which is easily tested for by trying to turn the handlebars with the front wheel locked between your knees.

Semantik

doug5_10 wrote:

Summary: Ribble R872, carbon steerer, ITM expander bung, Deda alloy stem and roughly 1500km on the clock so far.

Headset is coming loose after 30 - 40km with noticeable knocking over rough surfaces, and can feel play (pulling front brake while stationary and rocking)

*Note - I am preloading bearings correctly, tightening top cap before stem etc.*

Originally had a 5mm spacer above stem which though might not be giving enough room and the top cap may have been tightening against the bung. Changed this for a 10mm so that top cap and bung are definitely apart . . . and it has come loose again.

I don't have a torque wrench but stem bolts are as hand-tight as I dare (I've stripped stem bolts before!). I also tried tightening further when preloading the top cap but this just starts to pull up the bung. I can only think the the stem is slipping upwards slightly?

Not sure what else to try other than grip paste on the stem-steerer interface (and probably for the bung as well). Does this make any difference on Alu - Carbon, I thought it was mainly for carbon - carbon surfaces?

Having owned a couple of complete Ribble bikes myself and having experienced the same problem ON BOTH BIKES I am confident in saying the problem is with the headset and possibly the bung. Throw them both in your used parts bin and buy a decent branded headset and a decent branded fork bung. I replaced the poor quality headsets and bungs in both my bikes and replaced with 1)Ritchey WCS headset 2) FSA Orbit CE headset and Deda fork bungs. Never had a problem since.
You can snug everything back down again with your current headset as many times as you like but the problem is not going to go away. Ribble save money with these bike builds by including cheap components in the places most people don't bother to look, cheap and nasty headsets being the best example. They are just not made to the same tolerances as a decent branded one and they rust in double quick time- garbage is the only word for them.

PS -just seen that your bung is an ITM one- maybe worth giving that one another go with the new quality headset bearings.

keef66

Either the bung is being pulled up the steerer so you're not fully preloading the bearings, or the stem is moving up the steerer. Or possibly both.

Once the stem is clamped onto the steerer you could if you wanted remove the top cap and bolt. It's only function is to preload the bearings (and possibly keep out the rain).
So if it starts off OK then logically it can only be the stem slipping up the steerer.

Carbon assembly paste might be worth a go. I use it on a carbon seatpost in an alu frame to stop it slipping down. Very effective.

mfin

Deda Elementi bung like this tends to be one that doesn't slip, it's a design that seems to work great, I've used them a few times to replace ones that slip... this link isn't one that has stock but is the one I mean...

http://www.tweekscycles.com/components/headset-spares/deda-expander-bung

...I'm not familiar with the bung you are using, but a good deep design can be done up well so it doesn't slip without stressing a carbon steerer too much.

The stem side of things is a red herring, unless it's not tightened enough AND the headset adjuster bolt is working loose.

doug5_10

Dismantled and reconstructed everything tonight, think it is split ring shim that wedges against the top bearing that is coming loose. Its not a great fit and I'm pretty sure the top dust cap doesn't come down flush against it to keep it in place. Will see how we go, but may be shopping soon.

compuwiz_uk

i had a cx bike that i could not get the headset tightened fully for love nor money from day 1 in the same way as above.

lasted about 10 miles at most after adjustment before the looseness & wobble when brake testing the bearing for movement started again.

as you I tightened the bung that came with the carbon fork/steerer on the bike to within an inch of its life after many a cleaning it & the steerer etc & also top cap to the bung to the point of melding the 2 together ( needed mole-grips to fascilitate undoing the top cap bolt from the bung remnents & the bike whipping upside down to gather the rest of the bungs parts from the steerer tube in order to rebuild the bung - ordered a deda bung like in the last post & fitted that & its been problem free ever since

mfin

doug5_10 wrote:

Dismantled and reconstructed everything tonight, think it is split ring shim that wedges against the top bearing that is coming loose. Its not a great fit and I'm pretty sure the top dust cap doesn't come down flush against it to keep it in place. Will see how we go, but may be shopping soon.

Have you got a thin metal spacer between that split ring and the headset top cap? They are used to make sure the top cap does not touch the top of the head tube, not essential if it is already clearing with a small gap... worth checking that gap is there (when everything is tightened) while you are playing.

Only mentioned this to make sure everything is looked at, if it was touching you probably wouldn't get your symptoms, you'd more likely get some mysterious clicking.

The knocking/loose thing I still thing is your bung shifting up the steerer column or your headset adjuster bolt coming loose, particularly if you can set it up fine then it all works itself to knocking again.

Have you had someone else look at it? Headset issues usually aren't complicated at all, just some logic.

svetty

mfin wrote:

....Have you got a thin metal spacer between that split ring and the headset top cap? They are used to make sure the top cap does not touch the top of the head tube, not essential if it is already clearing with a small gap... worth checking that gap is there (when everything is tightened) while you are playing

This is often the problem - a thin shim on top of the bearing and under the headset cap will often resolve headsets that come loose.

I'd endorse the comments above re the bung slipping. I've only had one Ribble but it still has it's original headset after several winters use and it's still smooth and play-free....

wishitwasallflat

doug5_10 wrote:

... also tried tightening further when preloading the top cap but this just starts to pull up the bung ...

The bung only has two purposes:

1 to act as an anchor which the bolt through the top cap pulls up on to apply preload
2 to reinforce a carbon steerer where the stem tightens against it

It should not slip up when the pre load is applied. It must be loose if it pulls up, so replace it. If that doesn't fix the issue then something else is also contributing.

doug5_10

There is the wedged split ring shim that sits against the top bearing and a paper thin spacer that sits between that and the top dust cap. As I said, I'm pretty sure the shim has some wriggle room even when everything is tight down. I'm not sure on the bung though, even if it does get to the point that it starts to slip upwards, I seem to be able to fully preload the bearings and tighten the stem up with no play whatever, it only then loosens while riding. Any slippage from the bung or the top cap coming loose after the fact is surely null and void because the stem is already tight? I'm a pretty competent mechanic, LBS is only really used for the dark arts of wheel truing

compuwiz_uk

sounds like the trouble i had to me.

the bung was just rattling loose from the vibrations while cycling even though it tightened up fine indoors before the ride.

the bung i had was similar to this when i bought the bike new ( boardman CX team ) cant find an exact picture match but its close enough



& no matter how much i cleaned up the inside of the steerer or the bung & tightened it to what i assumed to be within an inch of its life ( far tighter than i preferred but i just wanted to get home so rammed on a handful of tightness for both the bung & the cap ) this lasted the most aount of time ( around 40 miles before it came loose again - this time i undid the topcap nut & out came the top half & bolt of the bung ( whooops ) fished out the bottom of the bung & the metal plate body of the thing from the steerer tube & then disconnect the topcap from the rest of the bung molegrips to the rescue )

that bung now resides in the spares box as i fitted a better bung (the deda style like linked to earlier when it was available to buy more readily ) & in it went fairly easily - couple of false starts due to piss poor fittign technique by me ( fitted it in the steerer in its full slack position & then could not get it to tighten up, needed fitting slightly pre tightened so just slid in the steerer hole requiring a slight bit of a tap on the steerer tube jiggle everything on the bung loose again if it stopped going in till it was completely inplace ) then it tightened down easily with normal pressures & never had a moments trouble since.

balthazar

doug5_10 wrote:

There is the wedged split ring shim that sits against the top bearing and a paper thin spacer that sits between that and the top dust cap. As I said, I'm pretty sure the shim has some wriggle room even when everything is tight down. I'm not sure on the bung though, even if it does get to the point that it starts to slip upwards, I seem to be able to fully preload the bearings and tighten the stem up with no play whatever, it only then loosens while riding. Any slippage from the bung or the top cap coming loose after the fact is surely null and void because the stem is already tight? I'm a pretty competent mechanic, LBS is only really used for the dark arts of wheel truing

Exactly right. As noted in comments above, the bung and bolt have no function after the stem is tightened.

From your further comments I'm even more convinced that the split shim arrangement is binding and preventing proper preload. If the shim is settling during riding, have you tried loosening the stem and tightening the head bearings then? If that doesn't work (the act of riding over bumps in effect doing the duty of a rubber hammer, forcing the bearing elements home momentarily), then I cannot visualise what is still wrong: it's a simple stack of bearings, races, and spacers after all. The fork crown and clamped stem represent absolute limits that nothing can move past.

Semantik

Just get a new headset

6wheels

doug5_10 wrote:

There is the wedged split ring shim that sits against the top bearing and a paper thin spacer that sits between that and the top dust cap. As I said, I'm pretty sure the shim has some wriggle room even when everything is tight down. I'm not sure on the bung though, even if it does get to the point that it starts to slip upwards, I seem to be able to fully preload the bearings and tighten the stem up with no play whatever, it only then loosens while riding. Any slippage from the bung or the top cap coming loose after the fact is surely null and void because the stem is already tight? I'm a pretty competent mechanic, LBS is only really used for the dark arts of wheel truing

I've had this problem, and this is how I put it right.

Take the fork off and give the steerer tube - where the stem locates- a rough up with 400 grit emery. This will help to remove any glazing thats on the steerer tube.

Then do the same with the stem, nice circular rub to break through the coating, as anodising does make any components very slippery. Give the steerer and stem a quick wipe and when assembling I do the top screw a little tighter than the bottom.

If that fails you need to get the vernier out and check for ovality. HTH

svetty

6wheels wrote:

.....Take the fork off and give the steerer tube - where the stem locates- a rough up with 400 grit emery. This will help to remove any glazing thats on the steerer tube.

Then do the same with the stem, nice circular rub to break through the coating, as anodising does make any components very slippery. Give the steerer and stem a quick wipe and when assembling I do the top screw a little tighter than the bottom.....

Just be careful if you go down this road as sanding the external surface of the steerer and the internal surface of the stem clamp will accentuate the difference in diameter making the stem a looser fit on the steerer - NOT what you need. You just need to ensure the surfaces are not slippery-smooth. Using carbon paste achieves the same thing without removing material......

I'm not sure about having one bolt tighter than the other either (and why the top one vs the bottom??). You should nip them up alternately a bit at a time to even the load until you reach the recommended torque figure quoted for your stem. Over-tightening by 1Nm is unlikely to cause damage but more than this isn't necessary and risks cracking.

I still think that it's more likely a bung slippage issue stopping you from getting adequate preload or the headset top-cap binding on the head-tube.....