Originally Posted by
rpenmanparker
Why do you need that custom steerer piece? Why not just remove the cap after the stem is tightened.
Need? Maybe not, but maybe. Hongfu provided a compression device with my fork that fits a full 38mm into the steerer tube. The impression that gave me is that they intend for the steerer tube to be fully supported in the clamp zone of the stem. It seems nearly every carbon fiber fork manufacturer expects a compression device to be used, too, so the idea of not using anything in the ID, or even one of the minimali$$$t expanders didn't sit well with me. But, the provided device weighs a ton (60 grams, or nearly 60% of the weight of the stem on my bike!) and I'm not guaranteed that it won't slip.
It's also an idea I've been kicking around in my head for years after two bad experiences with expanders, both of which had to be torqued just right not to slip but not too much so that they deformed the steerer tube. I won't lie that I got the idea from Aplha Q (I believe) who used to provide a simple sleeve and star nut with their forks, where the sleeve would be epoxied to the fork ID and the star nut driven in like it would be on a metal steerer.
Originally Posted by
Maelochs
What's up with that steerer-tube reinforcement? Is it simply a XF tube wedged down the steerer to reinforce it> I like the idea a lot. (Rathe,r I hated the weight of an expander, but the only one which didn't weigh a ton was pretty pricey on a gram/dollar scale.)
Not sure what a 'XF tube' is but it is a custom piece sized for a tight slip fit in the steerer tube and bonded in place with Loctite 648, not something I found that happened to fit. Here's a cross section of the part:
Nominal wall is 1mm to keep the weight down (18 grams on my scale) and there are M6 threads in the thick section to work with your typical headset cap.
My initial design goals of this piece were:
1. provide a non-slip means of adjusting bearing preload
2. reinforce stem clamping zone
3. further reinforce steerer tube at the upper headset bearing (hence the 60mm total length, enough to get below the upper bearing with my slammed stem)
4. simple installation (hence the lip at the top to prevent pushing it in too far)
I didn't initially intend to run this part without a top cap (I would have made some changes, and plan to in the future, for a cleaner final appearance assuming there is interest and I make more) but figured why not. I think it looks good enough as-is and I saw no reason to leave any protruding steerer tube above the stem given this solid reinforcement. I have the tapped hole plugged with a short plastic screw to keep water out.