No biggie: Fully remove the top cap from the expander plug. That should have a larger hex key bolt in the top of it, that you can use to tighten in place before putting the top cap back on.
Edit: That said, I’m curious as to why that lower wedge is that way up, as it looks like it *could* be meant to help expand the plug when tightened. Maybe another picture would help once it’s disassembled.
toast0ne on
Correct
jmorisoniv on
The top cap screws into an expander plug, part of which came out with the top cap. The other part of the expander plug, the wedge, fell off into your steerer tube.
Before doing anything, you should know that this means that you have a carbon fiber steerer tube, and that there is the right way to work on a carbon fiber steerer tube, and the way that potentially causes catastrophic failure of the steerer.
The expander plug in a carbon steerer tube servers two main purposes
1. Allows for preload of the headset
2. Provides support for the CF steerer against the compressive forces of the stem
Once you carefully remove the wedge from the steerer as many have suggested (if you do stick something in there to fish it out, be careful not to scratch the steerer or push the wedge further in), and remove the upper portion of the plug from the top cap, carefully reassemble the expander plug and then put it in the steerer. The top cap of the expander plug should sit flush with the top of the steerer. You will need to then tighten the plug (there’s usually a 5mm bolt in the expander) according using the specified torque. You will need to look this up – they’re all different. Start with the bike manufacturer’s website. You MUST USE A TORQUE WRENCH to do this, or you risk catastrophic failure of the steerer. If you don’t have one, just bring the whole thing to your local bike shop.
If you manage to reinstall the plug, you’ll have to reinstall the stem and top cap. Both of these must also be torqued to specification – see my comments above about a torque wrench and catastrophic steerer failure. You must also know that both stem clamping bolts should sit over the expander plug. This is because the expander plug serves to resist the compressive forces imparted by the stem on the steerer. You can’t just move the stem up and down without adjusting (cutting) the steerer to the appropriate length so that the expander can properly resist the stem’s clamping force.
I will likely get down voted for advocating for the use of a torque wrench. Great. Try it the other way and see how it goes…
3 Comments
No biggie: Fully remove the top cap from the expander plug. That should have a larger hex key bolt in the top of it, that you can use to tighten in place before putting the top cap back on.
Edit: That said, I’m curious as to why that lower wedge is that way up, as it looks like it *could* be meant to help expand the plug when tightened. Maybe another picture would help once it’s disassembled.
Correct
The top cap screws into an expander plug, part of which came out with the top cap. The other part of the expander plug, the wedge, fell off into your steerer tube.
Before doing anything, you should know that this means that you have a carbon fiber steerer tube, and that there is the right way to work on a carbon fiber steerer tube, and the way that potentially causes catastrophic failure of the steerer.
The expander plug in a carbon steerer tube servers two main purposes
1. Allows for preload of the headset
2. Provides support for the CF steerer against the compressive forces of the stem
Once you carefully remove the wedge from the steerer as many have suggested (if you do stick something in there to fish it out, be careful not to scratch the steerer or push the wedge further in), and remove the upper portion of the plug from the top cap, carefully reassemble the expander plug and then put it in the steerer. The top cap of the expander plug should sit flush with the top of the steerer. You will need to then tighten the plug (there’s usually a 5mm bolt in the expander) according using the specified torque. You will need to look this up – they’re all different. Start with the bike manufacturer’s website. You MUST USE A TORQUE WRENCH to do this, or you risk catastrophic failure of the steerer. If you don’t have one, just bring the whole thing to your local bike shop.
If you manage to reinstall the plug, you’ll have to reinstall the stem and top cap. Both of these must also be torqued to specification – see my comments above about a torque wrench and catastrophic steerer failure. You must also know that both stem clamping bolts should sit over the expander plug. This is because the expander plug serves to resist the compressive forces imparted by the stem on the steerer. You can’t just move the stem up and down without adjusting (cutting) the steerer to the appropriate length so that the expander can properly resist the stem’s clamping force.
I will likely get down voted for advocating for the use of a torque wrench. Great. Try it the other way and see how it goes…