I am currently building a bike up. I have a carbon fork, with a carbon steer tube, and I have to install it using a compression plug. I picked up one of these this morning:


I'm just wondering if anyone has done this procedure before. I'm thinking I might run into a problem getting the vertical tension right on the headset at the same time as the tension is correct on the compression plug. Also, should I be using installation paste?

  • Yeah. Torque wrench is an essential tool for carbon
    – user5901
    Jan 15, 2013 at 2:33

2 Answers 2


I think that the torque needed to seat the stem snugly enough is way smaller than that which would damage the steering tube.

And by the piece image and design, I would say the tension that is correct to seat the headset bearings is good to keep the plug inside too.

By the way, after you tighten the stem bolts, you could even take the plug out of the bike and ride it anyway (I had to do that some times, but just for a short period, of course...).

  • Thanks. FYI I found some step by step instructions here that were quite useful: bikeforums.net/archive/index.php/t-360915.html Nov 21, 2011 at 2:55
  • This is very old, but don't ever, ever EVER remove the expander afterwards on a carbon steerer. It is there partly because a hollow carbon steerer tube does not like being compressed by the stem and stembolts.
    – DennisK
    May 21, 2023 at 16:33

The top cap bolt doesn't actually bear any weight once everything is assembled. It's only there to get the stem in the correct position before you tighten the pinch bolts (and as a back-up in case the pinch bolts get loose). So that won't be a problem.

Also: composite materials are a lot more susceptible to damage from over-tightening things. Get a torque wrench for this job. Yeah, they're a little pricey - but if you can afford carbon fiber, you can afford a torque wrench.

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