Hey guys.
After about 10+ years oft mountainbiking I got myself a gravelbike last winter and I am struggling to properly mount the stem on the cf steerer tube ever since.
Long story short, this is what I’ve tried so far:
-) putting carbon mounting paste on the steerer tube (inside and outside) to increase the friction
-) upgrading to a bigger expander (the right one in the picture, which fully supports the steerer tube throught the entire height of the stem, the scale reads metric) so I can tighten the stem screws beyond the manufacturer torque without damaging the steerer tube.
-) after adjusting the steerer bearing with the top cap, I removed the top cap again and increased the torque of the expander and the stem screws in an alternating manner.
Are there any other secrets to mount the stem properly or did I just end up in an unlucky material combination between the stem and the steerer tube which will just not lock in?
I know it’s quite and old topic that was already discussed many times, but I’ve already tried most of the recommendations I could find online and i am bit desperate by now. So I thought it’s worth giving it a shot here.
by HolyHorst
8 Comments
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What’s the symptom that you are trying to solve? Headset becomes loose because the stem somehow works its way up on the steerer?
Usually there’s enough friction between the stem and the steerer to keep it in place with the stem tightened to 6 Nm or whatever is the maximum torque on the stem. The expander and the top cap should not play a role in keeping the stem from moving.
But with a carbon fiber steerer the expander plays a significant role in supporting the steerer from the clamping force of the stem. Your old expander is pretty useless in this regard, but the new one is one of those that I would consider really good.
Your stem is slipping on your steerer tube?
I guess that either your fork is undersized or your stem is oversized. What stem and fork is it?
How tight and hard is the stem to put on the steerer tube?
What is the stem material and brand?
Enve works better than even the longest plug. Also too much paste can result in slippage.
I forgot to mention that I have also put
-) grease on the expander wedges
-) locktight on the main screw of the expander.
You have to first tighten the nut in the comoression stem to 5nm then the top cap screw to 5nm. If im confusing i can show or explain it. Had the same issue with my new gravel bike. Learnd it from yt vid
What torque setting are you using for the expander?