4

I tried to find it online but I couldn't. I'd like to know recommended top cap torque too.

1
  • Top cap should not have a torque spec, as it is an adjustment that is done by feel to apply the headset bearing preload prior to tightening the two (?) stem bolts. The stem bolts DO have a torque spec, as they are what actually is clamping the stem to the steerer tube and MAINTAINING the preload that was initially set using the top cap. Now the compression plug, THAT could have a torque spec (I have had bikes where a compression plug had a designated torque spec).
    – Ted Hohl
    Jul 5, 2022 at 14:07

1 Answer 1

1

If you cannot find an actual torque spec for the compression plug, you can probably “rough it.” The purpose of the compression plug is two things: provide a fixture that the top cap bolt can draw against (to preload the headset bearings), and to support the inside of the carbon steerer against the clamping force of the stem bolts.

As long as the plug is not loose, it will provide the support needed, so that is not a critical torque. However, the plug needs to be tight enough to not slide when the top cap is adjusted AND to be tight enough to not loosen due to vibration while riding.

One additional note, on a carbon steerer it's possible to overtighten and expand the plug so that it slightly bulges the steerer, and then that may cause the headset to come out of adjustment after you think it's OK because the stem later moves slightly due to the bulge. Just a tip in case you have the headset adjusted properly but then keep finding it goes out of adjustment for seemingly no reason.

A more generalized search for compression plug torque listed 8 N-m for a 1-1/8” carbon steerer. I also found another source that mentions 8-9 N-m. So there are some ballpark-numbers that you can get you close.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.