how do I stop my headset coming loose

oldwelshman

These new headsets are a pain!!
Went for a 50 mile ride today and had to stop 3 times to tightem headset!!!
I adjusted it so there was no play in headset, then locked two allen bolts to lock handlebars and away I went.
15 miles later loose again on bum[y ground.
How tight do you tighten the steering bolts onto carbon forks? I tightened them again after adjustment and same again !!

redddraggon

Is it the expanding bung you are talking about? I'm guessing you are worried about crushing the carbon steerer, but you could tighten the stem up a bit more*.

*Disclaimer: if it all goes horribly wrong don't blame me.

meagain

Is it the aheadset OR the stem that is loosening (or I suppose both!)? Shouldn't need to rely on the stem clamp bolts to hold the fork/steerer securely. If the ahead, then is the star washer (or bung) firm?

Same disclaimer as redddragon!

System_1

Do you have a carbon steerer and therefore an expanding bung rather than a star nut, as it could be the expander slipping within the steerer tube. I had a similar problem which went away for a while after tightening the expander REALLY tight but in the end just bought a better quality one and haven't had a problem since.

oldwelshman

It is ahead i think with star washer.
I do not want to overtighten stem bolts as I have done them quite tight, would have to put extension bar on to get tighter !!
My understanding was that you adjust the aheadset allen bolt until no play in heaset then tighten the stem bolts.
I think that when going over bumps the stem must be moving a bit up the column and making the heaset bolt loosen slightly.
I guess I will have to try to tighten it more.

schlepcycling

Are the headset cups all installed and seated properly?. If the headset cups are not correctly and fully pressed into place then It could be that you're loading the bearings correctly then the securing it all in place with the stem only for the cups to 'move' (get pressed further into the headtube if you see what I mean) during use thus causing the headset to appear to loosen.

Park tools do a good 'how to' for headsets this one is installation and there's another one for adjustment.

http://www.parktool.com/repair/readhowto.asp?id=65

onbike 1939

^^^^ I'd agree with that and it's not something you should wait and see about. If the headset keeps loosening even after the stem bolts are tightened then you have a problem and the quicker you dissemble the headset and have a looksee the better.

Monty Dog

If you've adjusted the bearings to make sure there's no play, then you are reliant on the stem bolts to hold it securely. The star nut/ bung is only there to enable you to apply the right amount of end-load for adjustment, but after you tighten the stem bolts, you could wind it off and it shouldn't make any difference. If you're concerned about over-tightening the screws, either take it to your LBS or get a torque wrench. Running a big stack of spacers can cause problems too.

cee

expanding bung? :shock: sniggersnigger



Sorry ill get my coat

oldwelshman

Monty Dog wrote:

If you've adjusted the bearings to make sure there's no play, then you are reliant on the stem bolts to hold it securely. The star nut/ bung is only there to enable you to apply the right amount of end-load for adjustment, but after you tighten the stem bolts, you could wind it off and it shouldn't make any difference. If you're concerned about over-tightening the screws, either take it to your LBS or get a torque wrench. Running a big stack of spacers can cause problems too.

I also thought you could back off the star nut as I thought it was to adjust bearing ready to lock with stem.
I also thought as it was new the headset may have re seated itself, but not 3 times !!
I guess I need to tighten a bit firmer.

grahamharpin

This stuff is supposed to increase the friction between the carbon / carbon joint, maybe worth a try?

http://www.tacx.com/producten.php?fl=tr ... ce%20Tools

hamstercp

Just a daft thought...you have checked that the steerer tube isn't pulling out of the fork. It's not unknown for the bonding to fail on a carbon fork.

neeb

Do you tighten the top cap after you've tightened the stem bolts? I know it's the stem bolts that keep the headset in place and of course when you first tighten the top cap it's just lightly to get the pre-load correct, but for some reason I find if you do the top cap bolt up reasonably tightly after you've tightened the stem bolts it helps to keep everything in place.

Toomanybikes

get a locking headset spacer and put in on the steer tube, below the stem,

Get tthe headset bearings down nicely and then lock the heasdset spacer in place.

I greatly doubt the stem will move again after that is in place.

synchronicity

Once the stem is done up you can theoretically ride around without the top cap + expander bolt. Weenies do it just to save a few grams of weight. On an ahead system, the stem itself is what locks everything into place, not the bung.

What I tend to do is first tighten the expander bolt, tighten the stem bolts, then give the expander bolt another cinch to secure it into place (it won't add any more preload to the headset if the stem is bolted down well).

It is not normal for a headset to loosen itself 3 times in a ride... not even three times a year! This is why people tend to spec good headsets on quality bikes that see a lot of miles... Not just chris king. I've had good luck with FSA headsets too.

You could try getting a "cinch spacer". I don't know if that's the proper term... they come on all decathlon bikes. They basically act like a spacer, and you cinch them up along with the stem... it means if you flip the stem around or adjust the number of spacers you don't need to keep adjusting the headset preload tension. I think they keep everything nice and tight as a bonus.

neeb

This stuff is supposed to increase the friction between the carbon / carbon joint, maybe worth a try?

http://www.tacx.com/producten.php?fl=tr ... ce%20Tools

This stuff really works, I haven't tried it on a steerer but I used it on some handlebars that kept slipping even when the bolts were done up slightly beyond the recommended torque and it completely solved the problem. The stem manufacturer who recommended it said that some stem/bar combinations were just a little out in terms of widths etc by a fraction of a millimeter, and I guess the same could be true of steerer/stem combinations.

Just to go back to basics - how are you judging the tightness of the stem bolts? If you haven't got a torque wrench it's very subjective. Try cleaning the steerer and the inside of the stem clamp with acetone just in case there is some contamination there. Try to do the stem bolts up evenly, i.e. rather than tightening one all of the way then the other, tighten them each a bit at a time in turn. Apologies if you are doing all this already.

Nuggs

redddraggon wrote:

Is it the expanding bung you are talking about? I'm guessing you are worried about crushing the carbon steerer, but you could tighten the stem up a bit more*.

*Disclaimer: if it all goes horribly wrong don't blame me.

Thank goodness you've changed your avatar. I couldn't get the image of Cartman riding your new bike...