Originally Posted by
Bob Dopolina
I'm saying that you are not supposed to use a star nut on carbon. If there is an alloy sleeve bonded inside you should be ok. Looking at your photo it doesn't look like there is an alloy sleeve in there. It looks like raw carbon. Alloy is shiny and carbon is flat grey.
You first need to determine which you are dealing with.
The next question is about how much you are going to cut the steerer. If it so much that you can't tap the star nut deeper into the fork (and have it still be biting alloy and not carbon) then your only option is to cut the steerer to length and then go with a compression plug. If you are only swapping headsets and even stems the difference will only be a few mm. For this you should be able to tap the star nut deeper into the fork and trim what needs to be trimmed.
Do you have access to a star nut setting tool (every shop should have one)? It is important that the start nut is tapped down evenly so the threads are perpendicular to the axis around which the headset turns. If this is off it could result in a 'sticky' headset. This makes adjustment more difficult and reduces bearing life.
First, thanks for the help here. I really do appreciate it.
I understand that I can't use the star nut on a carbon steerer unless it has an alloy sleeve. I'm almost positive that it's not a carbon surface. I think it's an aluminum sleeve that's in there right now. Why would they use a light gray carbon on the inside of the tube and regular black carbon everywhere else? This and the fact that there was already a star nut installed leads me to believe it has an aluminum sleeve in there right now.
I don't have a star nut setting tool, but I could take it to the LBS for that.
I've never seen a starnut in a steerer loose enough to just 'tap' down. All require some sizable amount of force to move down the tube...
falling to the bottom and rattlin - not on the 3rd rock.
you could go too far for the bolt length, but Don;t DO That!
I guess I was thinking that if the star nut is inside the aluminum sleeve (assuming this is an aluminum sleeve here) and the sleeve is glued into the larger diameter carbon steerer, then knocking the star nut too far down would cause it to drop free into the carbon steerer tube. This seems totally possible to me.