Bicycle Mechanics - Facing head tube on a carbon fiber frame?

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paul_858
08-03-08, 01:19 AM
I noticed as I was assembling the bike that the chris king headset upper cup/bearing and bearing cap weren't lining up correctly.
It appears that the upper/lower cups may be out of alignment (parallel).
Is it common to have a CF headtube faced? Are the tools different than those used on metal frames?
Severian
08-03-08, 06:54 AM
No and there are no tools. If your CF frame is out of alignment then return the frame. TTBOMK You cannot cut carbon without destroying it. Do your best to make sure before you do anything drastic. Get a very good set of vernier calipers and measure the length of your head tube very carefully.
if it appears that your head tube is shaped more like a rhombus than a rectangle then you've got a bad frame.
Soil_Sampler
08-03-08, 07:16 AM
does your Calfee headtube have a metal insert?
did you use a headset press, or diy?
HillRider
08-03-08, 07:50 AM
does your Calfee headtube have a metal insert?
did you use a headset press, or diy?
Why do you think it's a Calfee frame?
Soil_Sampler
08-03-08, 07:55 AM
Why do you think it's a Calfee frame?
research.
http://www.bikeforums.net/showthread.php?t=447500&highlight=
paul_858
08-03-08, 09:46 AM
Yep there's a metal insert in the head tube. The headset was pressed by the shop when I purchased the frameset.
joejack951
08-03-08, 09:48 AM
How did you determine that the cup aren't lining up correctly?
paul_858
08-03-08, 09:56 AM
How did you determine that the cup aren't lining up correctly?
It's more of an assumption the cups are the issue.
Once I had the steerer cut, I went ahead and installed the stem/spacers/compression plug/cap.
When i tightened down the compression plug, the front of the bearing cap presents no gap between it and the cup. The rear of the cap has a gap, visibly noticable and also by touch you can tell there's an issue. When on the stand the the bars will rotate freely, but the moment you put any weight on the front end, the bearing cap is grinding against the cup.
Soil_Sampler
08-03-08, 09:59 AM
buy a new o-ring
paul_858
08-03-08, 10:12 AM
buy a new o-ring
I considered that as a possible issue so I pulled the cap. Rotated it 180 degrees and reinstalled. the point of issue is still the same.
Soil_Sampler
08-03-08, 10:20 AM
get the bottom of the stem faced.
paul_858
08-03-08, 10:27 AM
get the bottom of the stem faced.
As in squared? or are you suggesting that I have the bottom of the stem cut at an angle to try and load the rear of the cap more?
Soil_Sampler
08-03-08, 10:42 AM
As in squared?
yes.
http://www.chrisking.com/tech/tech_headsets.html#nothread
My headset seems to be adjusted correctly, but it binds when the bars are turned.
2. If it is a threadless system, the bottom face of the stem may not be perpendicular to the bore thus causing the bearing cap to cock and rub the cup. Solution: Face the bottom surface of stem square with steerer tube
paul_858
08-03-08, 04:02 PM
Replaced the stem with a new one, fixed the problem.
HillRider
08-03-08, 05:40 PM
Replaced the stem with a new one, fixed the problem.
It's nice to know Calfee didn't make a defective frame.
paul_858
08-03-08, 08:47 PM
agreed.
dvs cycles
08-04-08, 09:34 AM
It's nice to know Calfee didn't make a defective frame.It would not be his first if it was.
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