Originally Posted by
oldbobcat
By the way, I have never seen a butted steerer..
From Sheldon Brown:
Too Low! Danger!
Note: Steerers are butted at the bottom, so the hole in the steerer is constant-diameter until near the bottom, then the walls taper inward in the butted section.
It is vitally important that the stem extender (or stem) is not inserted so far that the wedge is installed where the steerer is narrowing, or it could come loose unpredictably.
When this happens, only the edge/corner of the quill or wedge contacts the steerer, and it is trying to "grab" a slanted surface.
This is sometimes a problem on smaller frames if you try to insert the stem or a stem riser too far down into the steerer.
Originally Posted by
oldbobcat
Because the Technomic has so much rise beyond the steerer, the leverage on its connection are greater. It therefor needs to extend further into the steerer, which explains why you're seeing the minimum insertion line. By cutting the stem down, say, an inch, you will lower the height and reduce the leverage. In a sense you'll be converting it to a "semi-" Technomic having more rise than a normal stem but less than an uncut Technomic. I would recommend cutting at least enough to bury the minimum insertion line.
Exactly!
Originally Posted by
oldbobcat
You might have to extend the threading on the quill binder bolt..
Agreed!
Originally Posted by
oldbobcat
A safer, less invasive work-around would involve purchasing a quill converter and a threadless riser stem. There'd be no cutting and machining and no question about getting a strong interface between your handlebar and steerer.
You'll have to pry my cold dead hands form the handlebars before you can make that kind of modification on my mid 80's Merckx Corsa Extra!