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Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

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Old 10-27-08, 02:49 PM   #1
drpaauwe
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Cinelli-style sloping crown fork. Diagnosis please.

Well, I bought this great Bob Jackson, used, this summer. Since then I've noticed very strong "speed wobble" except it happens even at like, 10 mph. Blazing fast, I know.

I thought maybe the frame was too noodly or I was too fat. Today I read somewhere (maybe something from Jobst Brandt?) and someone mentioned they had a cracked fork and it made that type of wobble worse. Then I definitely read something by JB that said Cinelli-style internally lugged forks can crack. Then I'm thinking about how it sounds like my stem has been creaking/popping when I stand up to pedal...
I looked over at my bike across the office...

I rode carefully home and pulled the wheel out of the front fork and here's what I saw where the right leg meets the crown:

and


I am telling myself this is just a crack in the paint, but I fear it is the leg separating from the crown.
What do you see?
If the fork is trashed, would that have been causing my wobble problem or is that more a function of the geometry of the frame and fork?

Help?
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Old 10-27-08, 04:51 PM   #2
Nessism
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Not sure but looks like the fork blade is starting to separate as you noted. If that were my fork I’d retire it before it puts you on your head.
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Old 10-30-08, 02:51 PM   #3
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The first fork I built had that crown, and it is doing the same thing. I know for a fact that I didn't get it hot enough and that there is probably not 100% filler penetration. Fork has been going strong like that for a number of years. I would at the very least mark the ends of the cracks with a fine point sharpie so you can monitor the cracks, and more idealy, I would retire the fork. If you keep riding it, keep a close eye on it.
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