coasting 

I want to drop my handlebars just to experiment with lower riding position, but i don't know if that's how i want to position the bars in the long run so i don't want to cut it down just yet.

is it safe to just lower the stem below the expansion plug so the plug isn't giving outward force where the clamp will be exerting inward force?

Nate552

You just put the spacers on top of the stem so that the top cap is putting pressure on the spacers.

merlinextraligh

yes. move the spacers below the stem instead of above it, torque the stem to spec and you'll be fine.

jsharr

I think the OP may have a carbon steerer and is asking about the additional internal reinforcement given by having the expander plug in the area of the steerer that the stem clamps to in order to avoid crushing the steerer.

I would contact a selling dealer of your bike if it is a stock fork and ask their advice.

DaveSSS 

I agree, but don't go crazy tightening the clamp bolts. The 5Nm that's commonly recommended is plenty.

merlinextraligh

It's done everyday with carbon steerers. In fact what the OP is suggesting doing is going to be safer than he started. By lowering the stem, and reducing the spacers between the headset and the stem, he's reducing the amount of leverage on the steerer tube.

In fact, many lower level domestic pros, who are given free bikes each season, don't cut their steerer tubes, and run spacers above the stem, so that they can resell the bike next season when they get a new free bike.

Assuming that he wasn't running too many spacers for the spec of the steerer tube to start its not going to be a problem


If you're relying on the expansion plug to not crush your steerer, you're over torquing the stem bolts.

The key here is tightening the stem to spec. Buy a torque wrench.

coasting 

thanks for the replies so far.

as some have mentioned, i have a carbon steerer and the initial stem height has 3x10mm spacers underneath on top of a low fsa IS2 integrated headset . it causes no discomfort but it is a bit high so i want to see what is the lowest i can go without causing pain, before i get the final cut done for steerer.

I want to take out 2 spacers from below and as there is already quite a bit of steerer above the stem, it's a bit tricky to set the expansion plug down lower. so i intend to just leave the plug alone and move the spacers above the stem, but only if it is safe to clamp the stem without having the compensating outward force from the plug.

when you have taken out spacers, is that all you did or did you move the plug down also? if you didn't move the plug, were there any bad effects?

merlinextraligh

20mm of spacers above the stem is just not going to be an issue, and you don't need to move the plug down.

Many CF steerers spec no more than 40mm of spacers below the stem, so your total number of spacers isn't an issue, and as said above, moving 2 spacers above the stem actually decreases the forces acting on the steerer tube.

I've got 20 mm of spacers above the stem on an Alpha Q tandem fork right now.

The expansion plug is in the steerer to give you something to thread the top cap into to preset the load on the headset bearings. It's not there to support crushing forces from over tightening your stem.

If you're really worried, go the website of the fork manufacturer and look at their technical information.

coasting 

thanks merlin. i guess i'm just a bit nervous about carbon forks. it is a real design HP signature fork and you might have one on your merlin too. not much info on the real design website so i'll email them.

thirdin77

Check your owner's manual.

I know Cannondale's manual includes a pamplet about how to adjust the expander plug/carbon steerers and how not to mount the stem.

Camilo

What kind of fork are you using?

Soil_Sampler

re-read.