Compressor plug for carbon steerer - any recommendations?

[moose8]

My bike's headset just won't stay tight - it is all carbon (fork and steerer and frame) and no matter what it loosens. It appears to be because of a cheap plug or nut or whatever it's called. A guy working on my bike suggested if it loosened after my last long ride I should look into a expander plug. It loosened after it had just been tightened, so now I am looking for one. I found one from FSA but was wondering if anyone has any suggestions for such a plug for use in a carbon steerer, or if they are just all the same. Thanks. Here's the one I was thinking of getting:

http://www.amazon.com/FSA-Compressor-Black-Expander-Plug/dp/B002SR1GT2

[kurto]

That one should suffice. If you want something in a particular color, check out the KCNC http://fairwheelbikes.com/kcnc-expander-plug-p-1189.html

[oliver1850]

How long has the bike been built up? Sometimes crown race or cups can seat more completely when riding, leading to loose headset.

I've used FSA and Reynolds expander plugs with no problems, although I believe a bonded in plug is the best way to go.

[moose8]

How long has the bike been built up? Sometimes crown race or cups can seat more completely when riding, leading to loose headset.

I've used FSA and Reynolds expander plugs with no problems, although I believe a bonded in plug is the best way to go.

The bike has been built around a year and a half

[Mark McM]

I think you mean the expander plug (expands to grip the inside of the steerer tube).

If the headset won't stay in adjustment, it is doubtful that it is the expander plug. The job of the expander plug/top cap is for setting the initial headset pre-load. Once the pre-load is set, the headset is locked in place by the tightening the stem on the steerer tube. After the stem is tightened, the headset should stay locked into adjustment even if you remove the expander plug. (Note: Some carbon fork manufacturers recommend leaving the expander plug in place to help reinforce the steerer.)

As mentioned, one possibility is that the crown race or cups haven't completely seated. Or, the stem may not be properly tightened on the steerer. Or, the bearing race seats may not be cut square (or the bottom of the stem clamp may not be square). Or, it is even possible that the steerer itself is cracked/damaged. In any case, you should get the to bottom of what is causing the headset to loosen.

[gavingould]

No issues with FSA units on road and cx bikes here. Proper adjustment and torque are paramount.

[rando]

If it loosened while you were tightening the screw into the top cap, before locking down the stem, it can not show for a couple miles. Unless there is a gap between the top of the steerer and the expansion plug that is not your problem though.

[eddief]

http://forums.thepaceline.net/showthread.php?t=133109&highlight=enve+plug

[R2D2]

I think you mean the expander plug (expands to grip the inside of the steerer tube).

If the headset won't stay in adjustment, it is doubtful that it is the expander plug. The job of the expander plug/top cap is for setting the initial headset pre-load. Once the pre-load is set, the headset is locked in place by the tightening the stem on the steerer tube. After the stem is tightened, the headset should stay locked into adjustment even if you remove the expander plug. (Note: Some carbon fork manufacturers recommend leaving the expander plug in place to help reinforce the steerer.)

As mentioned, one possibility is that the crown race or cups haven't completely seated. Or, the stem may not be properly tightened on the steerer. Or, the bearing race seats may not be cut square (or the bottom of the stem clamp may not be square). Or, it is even possible that the steerer itself is cracked/damaged. In any case, you should get the to bottom of what is causing the headset to loosen.

I'll add one other point that may come into play. Sometimes the top cap can come in contact with the top of steerer tube. Make sure there is enough space between the two.

[moose8]

Eddie - I sent you money for the enve one. Why not bling it up on the cheap?

As to all the other replies, thank you, and man if it's not one thing it's another. I had a super bad accident with a bad headset so you guys have me running scared. This is definitely one for the bike shop to deal with. Good thing my hoarding tendencies mean I have 7 other bikes to use, though I fear since I got engaged the extreme bachelor tendencies may have to come to an end because I guess some people don't view bikes as decorative in a one bedroom apartment.

[John H.]

My headset kept coming loose with the Enve plug.
I switched it out for a Specialized plug and now my headset stays tight.

[eddief]

as has been said, stem fixing bolts are loose, crank down the correct torque on the expander so the steering column does not have play in it when the front brakes are applied and you rock the bike back and forth...and the steerer works smoothly left to right in the headtube/bearing complex. Then you properly torque the stem bolts...then the plug is more or less not in the picture at all. The Enve top cap is beveled on the underside and I think that bevel makes it so you have to use a 3-5 mm spacer under the top cap. Without the spacer cranking down on the expander bolt will not work correctly.

This guy from Enve makes it all to damn clear:

https://www.youtube.com/watch?v=cQe9TJJq1PE