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Old 12-01-08, 08:49 PM   #1
Isocline
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Bent Steerer Tube Repair

Hello All...

I have a 1984 Centurion Pro Tour 15 that I picked up last week for cheap

The only repair needed is the bent steerer tube. If you know this bike, you know that the fork is pretty
speacialized. It has mounts for the cantilever brakes, and its got some chrome and stuff. I LOVE this bike frame and can't wait to ride it.

I've been told by a couple frame builders that this tube can be straightened.... I don't see any cracks in the steel. The tube is Tange #2, the frame is chromoly.....

I attached a couple pics. What do you guys think I should do if I REALLY want to use the original fork?


Here is a link to the Fork Pics: http://www.downtowndj.com/StuffandThings/Fork.zip
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Old 12-01-08, 11:14 PM   #2
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Looks repairable, I'd replace the steerer tube. Pretty easy job although it will need repainting.
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Old 12-01-08, 11:36 PM   #3
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Ok, replacing the steerer tube is something I hadn't considered. The fork itself would need repainting? Is the steerer tube welded to the crown? Are there people who can do this for me? My girlfriends dad works with steel welding at a yacht company....he asked me about replacing the tube, and I didn't know what to tell him. So many questions
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Old 12-02-08, 08:40 AM   #4
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The steerer tube is brazed to the fork crown. To remove the old tube the crown would have to be heated and the bent tube pulled out. Another way to get the old steerer tube out is to drill or grind it out. No hack jobs allowed; you need to maintain a tight between the crown and the new steerer tube so go easy if you decide to grind the old one out. Heat on the crown will destroy the paint, either during removal and/or during installation of the new steerer. It's best to remove the paint before hand on the upper portion of the fork or it will smoke and burn when the fork is heated.

Hope this helps.
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Old 12-02-08, 09:12 AM   #5
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Ok...this getting good. I DO have a torch and 10 years of experience with brazing HVAC coppper pipe with silver solder. Maybe this is a dumb question, but: With what is the steerer tube brazed with? Solder?
Is it similar to unbrazing copper? Thanks a bunch for your help! I've looked through the forum and can't find any info on this.

Finally, I suppose I'll need to order or machine a new steerer tube? Sorry for all the questions, but I love this bike. I'm planning a 70 mile ride to a campground in GA on New Years...:-)
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Old 12-02-08, 09:14 AM   #6
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Also....the frame is chrome underneath the paint....might look dope with just a chrome fork. Otherwise I could repaint, but the decals might pose an issue....maybe I could take them off with a chemical and save them....Anyway...just rambling...
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Old 12-02-08, 11:35 PM   #7
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Honestly now, all this information is available in the archives so dig deeper for more information on things like brazing materials and such. That said, I'll get you started...there are two common brazing materials used for bicycles: brass and silver alloy. Most likely your bike is brazed with brass. You can get pre-threaded steer tubes from various sources (do a search), and welding supply stores can provide you with brass brazing rods and flux. You will also need a proper torch, not a bottle of propane. And make your self a fixture to hold the fork into alignment while you tack the steerer into place.

Good luck.
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Old 12-03-08, 07:48 AM   #8
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Thanks I was just using the wrong search terms. Brass brazing....on it
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Old 12-03-08, 10:33 AM   #9
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Ok...just to update. After some more research: I think that removing the crown race (without damaging the crown), machining a new keyed, 1", threaded steerer tube sounds like too much work. I found a similar fork at my LBS for 40 bucks....I'll post some pics when I'm done.
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Old 12-03-08, 07:38 PM   #10
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Quote:
Originally Posted by Isocline View Post
Ok...just to update. After some more research: I think that removing the crown race (without damaging the crown), machining a new keyed, 1", threaded steerer tube sounds like too much work. I found a similar fork at my LBS for 40 bucks....I'll post some pics when I'm done.
You wimped out.
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Old 12-04-08, 08:34 AM   #11
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Well, honestly...I'd like to ride the bike soon and searching for "unbrazing" etc., on the forum didn't yield many results that I felt applied to directly to replacing a steerer tube. In fact, I can't find one article on the net anywhere that specifically addresses the process. I found another frame builder's forum, but its going to take a while to derive specific instructions from that archive of material...its comprehensive to the extreme.

I want to repair the damaged fork. However, I don't feel like I completely understand the process and I'd hate to permanently ruin it..its a beauty.

I know that its not anyone's responsibility to walk me through it, but I'd like to do it right. Even if that means taking it to a frame builder.
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