Symox

hello,
I'm a DIY mechanic and was inspecting my bike's fork and noticed that the compression/expansion nut wasn't centered on the stem bolts. Upon removing it I realized that it was not as long as the stem's height (please see pics). I don't know if this is normal but it appears this expansion plug was only placed to allow preload of the fork as it wasn't so tight that the spacers wouldn't slip back and forth easily. This is for a 2007 Specialized Roubaix with a carbon fork/steerer tube

Questions:
1) Should I replace with an expansion bolt that is as tall as the stem?
2) Should I just recenter it and not overtighten it (6nM ish) and live with it?

Thanks for the help!

Andrew R Stewart 

1- Sure, especially if you will sleep better for it.

2- Sure and it will likely work well. Just don't over tighten the stem binder bolts. Andy

FBinNY 

Sorry, but you're missing something (or at least it doesn''t show in the photo).

What you show is not a true compression plug (unless it has an internal thread and a screw to engage the top cap)

I make the point because you seem to misunderstand what the compression plug is about. It's to provide a "nut" fixed in the steerer (think star nut in traditional threadless systems) that will accept a bolt that can be tightened to push the stem and any spacers down and "compress" or preload the headset.

This particular design is intended to provide isolate plug producing a fixed force against the steerer, allowing it to stay put,without glue, and not expand farther as the top screw is tightened. It's height/depth doesn't matter as long as it's within the working reach of the top cap bolt.

So, the sequence is as follows. Locate and tighten the expander enough for it to stay put, and avoid the temptation to overtighten. Assemble fork, headset, spacers, stem, top cap and bolt. align stem to front wheel, tighten the bolt to preload headset, then tighten stem buts to keep everything locked together.