Originally Posted by
steve-d
My question pertains to the HS tightening plug. A mechanic I know said the plug does two things: (1) tightens the HS so the bearings are properly pre-loaded; and (2) it provides internal support to the carbon steerer tube so when the stem is clamped the tube won't break.
Your mechanic is correct.
The FSA expansion plug is easy to use but the one I had did not offer enough support behind the stem (not long enough to reinforce the steer tube behind the stem clamp).
To avoid cracking the steer tube I recommend that you not exceed 5 nm when torquing the stem clamp.
Al