Originally Posted by
Road Fan
1. You need to have the portion of the quill that will expand, be it conical or wedge, to apply pressure below the threaded area of the fork. This is what limits how high a given stem can be raised... If you don't do this there can be a stress riser in the steer tube material, and the threaded area has sharp edges which impair the strength of the steer tube to such stresses.
I was thinking about this while riding my commute home this evening. (My commute gives me more than hour each way to run my own thoughts without interruption. Everyone should have that luxury every so often.
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I confess I've never heard this reasoning before. I always assumed the minimum insertion line was so that you'd have enough length of contact, not that it was related to the threads. But it doesn't matter whether I cut the steerer tube or not. The depth of the threads down the steerer tube into the HT is what it is. Having 11mm extra on the top of the steerer tube simply means that I should insert the stem 11mm more than the mark on the stem,
assuming the threads are cut to a typical depth down the tube. I don't think inserting the stem that far will be a problem as it fits into the steerer that far and more with no trouble. Whether the handlebar will be high enough for me is still a function of the stem, not how high the steerer comes up. The only limitation created by the extra length would be to limit how far
down I could put it. Anyway, from my "all my bikes are different and they all fit" perspective 11mm isn't so much.
On the question of whether it is the original fork, I would have expected that, if there is any standard practice to this at all, the length of threads on the steerer tube would correlate to the HT length. Which is to say that if the fork was meant for a longer HT then the threads wouldn't extend as far down toward the fork crown. In fact they extend quite a ways, plenty far for the bearing race not to run out of threads. It suggests that the fork was meant for this frame but the steerer tube was left longer by the factory, perhaps so that the owner could have it cut after the headset was chosen.
After looking at the headset with four 3mm spacers in place I've decided that I like how it looks. It is certainly distinctive. The shiny bright aluminum spacers are a perfect match for the bright finish on the headset and the chrome of the fork crown, giving the front of the bike a sparkly appearance. I can always remove them later just like I can always seek out another stem if I can't make this Cinelli work.
Assembly begins this weekend!