[C-Dawg]

Ok, so I had a Salsa El Mariachi built up last week with a niner carbon fork. I had this fork on another frame previously. That previous build didn't last very long 'cus I damaged the frame while working on it (long story, I'm dumb). Anyways, the fork was moved over to this new frame and after a ride or two, the step has loosened enough to where there is some slop in the headset. I had this same exact issue with the previous build while it lasted. I have to loosen the stem bolts, then tighten the top cap back down, then retighten the stem bolts to get it all tight again. I'm using a torque wrench and tightening to approx. 5 ft.lbs. Does anyone know of anything I can do besides getting more carbon assembly compound? Can I tighten the bolts a little tighter than a little over 5 ft.lbs.? I'm terrified of going too tight on a carbon steerer. Besides that issue, the fork is awesome!

Obligatory new bike pic attached.

 

[PeopleForScience]

Did you try a different stem?

 

[C-Dawg]

I have a Thompson on there now. I've also tried an Easton Haven stem. Both have the same result.

 

[wrich73]

what kind of headset do you have?

 

[GRAVELBIKE]

Which expander are you using? I've found that a longer expander works much better in forks with carbon steer tubes.

 

[rinkle]

I once had the same problem with a steel fork. It ended up actually being the top cover assembly of the headset was bad. It didn't seat right. So it would feel like it was tight but would loosen up while riding it. It took awhile to figure it out.

 

[C-Dawg]

The headset is a brand new cane creek 40.

The expander I'm using is the one that the fork came with.

I hope it isn't the headset, it's brand new! These also seem to come highly recommended as well.

I rode it again today and it seemed to stay tight, but I tightened everything up a smidge more before I rode. I'll try some more carbon assembly compound. I'm pretty paranoid about these issues, especially since it is a carbon fork. Maybe I'm just not cut out for a carbon fork, lol. The idea of it shattering has me terrified.

 

[wschruba]

It can be helpful to use a torque wrench to set the expander in the tube. The top cap bolt should not exceed the torque you used to install the expander.

Also: double check that you have the split, wedge-shaped ring pressing on the headset bearing. Without it, you will either never get rid of the play, or the headset will feel fine testing in the stand, but after your first stop, will jar loose.

 

[GRAVELBIKE]

If the expander is the one I'm thinking of, replace it with one like this:

Also, make sure your top cap is not bottoming out on the top of the steerer.

 

[ozynigma]

Also, make sure your top cap is not bottoming out on the top of the steerer.

Ditto, I had this happen took ages to figure that the couple of mm the top cap appeared clear was being compressed out by the top bolt. I put an extra 5mm spacer between the top cap and stem (which is one way to solve it.)

 

[kwarwick]

The expander and top cap's job is really only to assist with setting pre-load on the headset bearings... once you tighten the stem down completely these pieces no longer perform a function (other than filling the hole in the top and perhaps preventing the stem from crushing the steerer tube).

If you are able to get everything setup without any play and some play develops after riding then the problem is almost certainly with the interface between the stem and the steerer tube. I've had similar problems with carbon steerer tubes and the one thing I found that really helped was to clean off any traces of oils or grease on both the steerer tube and the inside clamping surfaces of the stem. Rubbing alcohol does a pretty good job. If that doesn't work then you can try the carbon assembly compound, but I've never found that necessary after clearing with rubbing alcohol.

 

[C-Dawg]

Thanks for all of the replies! I haven't replied sooner because I haven't had much time to ride and test out after re-tightening everything down. I've had 3 rides without having to go and re-tighten the top cap and stem. It seems to be holding fine now. The main thing I thought of before posting this question was the top cap bottoming out, which is the main reason I have a small spacer above the stem. I hope this isn't a no-no, the top of the stem is still a mm or so above the top of the steerer tube. If problems come back, I'll first clean everything up really nice and dry and reapply carbon assembly compound. Everything that is being tightened down to carbon is done using a torque wrench to prevent me from having a bad day. If that doesn't work, I'll try a new expander. Thanks for all the tips!

 

[J3SSEB]

I had the same issues on a Niner fork too. All it needed was an extra spacer below the stem cap.