Originally Posted by
rosefarts
It seems that no matter how tight the stem is, the steerer is slick enough to gradually loosen.
OK, good to know. This has not been my experience, though, on two aluminum and one steel steerer. I can see how this might happen on a carbon fiber steerer since the stem bolt tightening torque is more critical (and probably less).
On one of my bikes, the factory instructions for adjusting the headset are:
1) Loosen stem bolts
2) Tighten top cap to eliminate play in headset
3) Tighten stem bolts
4) Tighten top cap to a specified torque.
It would seem to me that if the stem were able to slide on the steerer, step 4) would result in excessive headset bearing tightness.