I just obtained a carbon fork for my bike and was going to use the threadless headset I used previously.
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.
I don't know if the internal support assertion is accurate. If it is, then I'd need a new plug as it doesn't provide support throughout the length of the steerer tube being subjected to the clamping load of the stem.
Any insight or advice?