Slipping Star Nut / loose headset

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Slipping Star Nut / loose headset
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Posted: May 10, 2021 at 11:10 Quote
Hey guys, I'm hoping someone here will have a few new ideas for me.

The headset on my Ibis Ripley (3 years old) wouldn't stay tight so I had my LBS replace it (100% new parts) with the same original factory Cane Creek parts.

Now, I've ridden 3 months on the new headset and since day 1, I go ride and the headset loosens up during the ride. I'd come home and feel the slop between headset and frame, unscrew the stem bolts, then do a quarter turn on the headset bolt, re-tighten the stem bolts (torque'd to spec). Cool - problem solved, right up until I go ride again.

Then I'd ride, it'd loosen up and I'd repeat the process until I pulled the star-nut right out of the top of the tube.

So now I've replaced the star-nut, used the Park Tool to set it in properly and torqued everything up, confirmed the right spacers - around 3mm of gap below the cap - it all fit and worked perfectly when new. Everything felt great, and then after the ride, the darn thing is loose again.

I'm fairly sure the star-nut is just creeping up the steerer tube again.

I'm not sure what to do next - I've replaced everything in the area and it just won't hold pre-load. I can't see any damage to the frame, and the LBS would have called that out to me. It's new parts everywhere.

Has anyone seen this before / have any good ideas to deal with a situation like this?

**edit - I'm abour 200 lbs fully geared up - that shouldn't be a problem

Posted: May 10, 2021 at 13:12 Quote
What fork is it your running?

Star nuts can sometimes slide upwards on steel steerer. You can either try lashing another star nut down the steerer and using a longer bolt to thread into both star nuts,or you can use an expander wedge for carbon steerers

Posted: May 10, 2021 at 13:20 Quote
felimocl wrote:
What fork is it your running?

Star nuts can sometimes slide upwards on steel steerer. You can either try lashing another star nut down the steerer and using a longer bolt to thread into both star nuts,or you can use an expander wedge for carbon steerers

Thanks!

It's a Fox Factory 34 mountain fork.

I was thinking about the second star nut option - I'll give that a shot

Posted: May 10, 2021 at 13:38 Quote
A star nut's job is not to hold the stem on. Its job is to preload the bearings. It's the stem's job hold everything together. You can actually remove the top stem cap after you've tighten the stem on properly.

Looks like the issue is with the holding power of the stem.

Posted: May 10, 2021 at 14:56 Quote
the-one1 wrote:
A star nut's job is not to hold the stem on. Its job is to preload the bearings. It's the stem's job hold everything together. You can actually remove the top stem cap after you've tighten the stem on properly.

Looks like the issue is with the holding power of the stem.

Fair point. If I'm tightening the stem bolts to spec (5nM) and it's slipping, what should I try next?

Posted: May 10, 2021 at 15:24 Quote
This sounds terribly wrong. The star nut is not the issue. As stated prior, it only preloads the bearings. Is it possible that you are torquing the stem to the lip of the top cap? Do you have a spacer on top of the stem? If everything is correct as you say, then the issue is with the stem, which sounds odd to say the least. Not uncommon for the stem and bars to twist together from something but to have it come loose is not.

Posted: May 10, 2021 at 15:36 Quote
Mountainfrog wrote:
This sounds terribly wrong. The star nut is not the issue. As stated prior, it only preloads the bearings. Is it possible that you are torquing the stem to the lip of the top cap? Do you have a spacer on top of the stem? If everything is correct as you say, then the issue is with the stem, which sounds odd to say the least. Not uncommon for the stem and bars to twist together from something but to have have it come loose is not.

Hey Frog - thanks for this. Agree it's weird. I don't have a problem with the wheel staying true (forward) after torquing everything in place, so I don't think I'm hitting the stem to the lip of the top cap - but I will 3x check that tomorrow AM.

Posted: May 11, 2021 at 8:52 Quote
cr3ynolds wrote:

Fair point. If I'm tightening the stem bolts to spec (5nM) and it's slipping, what should I try next?

If it is still slipping at 5nM, then try 6 or even 7nM. Just be careful not to strip or snap the bolts.

Posted: May 11, 2021 at 15:01 Quote
What is very weird too is that your stem is obviously moving up over time, but never rotates? This seems very unlikely to me. On a strong impact, or even a sudden change of direction while riding, if the stem is not fixed to the steerer, it should rotate (which is really dangerous, as it would likely result in a crash).

I don't see how it would only ever move up in a perfectly aligned way.

Posted: May 11, 2021 at 16:12 Quote
Most likely it’s just not tightened enough in the first place. I have a Ripmo and have ran into a similar issue where the headset feels 100% tight in the shop, but after a ride it loosens up just slightly to create a knock in a rock garden. Another 1/4 turn on the preload and it’s good to go and doesn’t loosen back up. I just attribute it to the seals settling in after service.

Posted: May 12, 2021 at 6:58 Quote
I've been following this thread the last couple days and out riding yesterday, it occurred to me that if the bike is developing a knock in the headset area, but the stem is not loosening, then the likely culprit are the spacers. If they are plastic or a very soft metal or damaged, then one could set the bike up on the stand and everything would work well; however, after an impact, these could compress, causing play.

My diagnosis also assumes that the crown race is properly seated and the bearings are free of play and installed in the proper direction. I am also assuming that the headset is complete and installed correctly. Since OP mentioned that the shop adjusted things, I hope the above is true; though, to be sure, just because an LBS does the work does not mean it was done correctly!

It cannot be the star nut because as we all know once the stem bolts are tight, the star nut no longer factors into the equation. Plus, when a star nut pulls through, it scores the inside of the steerer, leaving noticeable scrapes. It also does not seem likely that the stem is loosening because OP tells us that the stem and wheel remain aligned. If there were not enough gap or if the stem loosens, the bars would not remain aligned with the wheel.

Posted: May 12, 2021 at 18:34 Quote
thanks to everyone for the ideas.

Today I re-torqued the stem bolts and then secured them with hi-strength loc-tite, and I think that may work.

someone mentioned the star-nut pulling up and scoring the inside of the steerer tube - yes, totally. this picture was of the old star-nut that got pulled thru. So yes, lots of scoring as it made it's way up inside.

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