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Old 02-19-09, 07:10 PM   #1
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Threaded fork/stem problem

I had my threadless fork threaded at a local shop. My problem is, the quill stem only goes down about half way. When you take it apart, there is definitely enough room for it to go down further. Even if I take the bottom part of the stem off it still goes down the same length. I can look down the steer tube but I don't see anything impeding it. I took it back to the shop and they couldn't figure it out either. They said maybe I could hone it out a bit? The bars sit at a decent height, but I just want adjustability if I ever go with different bars. Any ideas?
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Old 02-19-09, 07:13 PM   #2
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I had my threadless fork threaded at a local shop.
Are you serious or did you actually mean you had threads extended?
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Old 02-19-09, 07:20 PM   #3
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The fork was made for a threadless headset/stem and I had a threaded headset installed. Honestly, I'm not sure of the process involved. Its the only part of my bike I didn't build because of lack of tools to do it.
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Old 02-19-09, 07:27 PM   #4
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Oh, I know your problem. A lot of threadless forks have a butted steerer. That is, the wall thickness changes along it's length, usually getting thicker as it get closer to the crown. I'll bet that's your issue. Threading a threadless steerer is not at all recommended. Even if it's not butted, the inside is not designed to take a stem and probably has an uneven finish. You could have a machine shop machine the inside of the steerer to an even diameter but that's DEFINITELY a BAD idea.

Get a fork with a threaded (from the factory) steerer.

edit: getting it machined/reemed wouldn't be a bad idea - it's be a HORRIBLE idea. Feasible - but only if you don't value your own life.

Last edited by GV27; 02-19-09 at 07:34 PM.
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Old 02-19-09, 07:32 PM   #5
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Gotcha...It seemed as if the quill had a slight taper, but now that makes more sense. Guess I'll learn to live with it. It hasn't been a problem yet...
Thanks for the info!
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Old 02-19-09, 09:39 PM   #6
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Originally Posted by generate View Post
I had my threadless fork threaded at a local shop. My problem is, the quill stem only goes down about half way. When you take it apart, there is definitely enough room for it to go down further. Even if I take the bottom part of the stem off it still goes down the same length. I can look down the steer tube but I don't see anything impeding it. I took it back to the shop and they couldn't figure it out either. They said maybe I could hone it out a bit? The bars sit at a decent height, but I just want adjustability if I ever go with different bars. Any ideas?
Butted steer tube?

Small frames (short steer tubes) in particular my have this problem when the bottom of the stem hits the beginning of the butt at the base of the steer tube. You don't really want to ream it to allow the stem to drop lower. The butting is somewhat gradual to prevent a large stress raiser at the transition. Reaming will remove this taper and cause more concentrated stress, possibly leading to steer tube failure.
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Old 02-20-09, 06:31 AM   #7
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So the basic problem is that you can't get the handlebars low enough with a quill stem? What kind of stem are you using, and what is it's angle?

I have a couple of Columbus -tubed bikes, and they have a spiral reinforcement in matbe the bottom 5 cm of the steer tube. Combined with my small frame sizes and the extension limit, I really can only put a quill stem at one position if it has an angled clamp.
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Old 02-20-09, 05:34 PM   #8
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Butted steer tube?

Small frames (short steer tubes) in particular my have this problem when the bottom of the stem hits the beginning of the butt at the base of the steer tube. You don't really want to ream it to allow the stem to drop lower. The butting is somewhat gradual to prevent a large stress raiser at the transition. Reaming will remove this taper and cause more concentrated stress, possibly leading to steer tube failure.
edit: ah, never mind - you're saying the same thing I was......at first I thought you were saying I was nuts for suggesting the steerer was butted.

THe steerer on my RockShox SID fork is what DT (I don't know if anyone else does or not) would call "continuous butted" - the wall thickness just starts tapering from where it goes into the crown clear to the top. Which is a bit strange as a cut steerer is stronger both because it's shorter AND it's average thickness is greater......to get it to an even thickness no way you could hand ream it - you'd need a machine shop to do it on a lathe.
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