Rear Derailleur mounting bolt thread?
07-04-08, 04:21 PM
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Rear Derailleur mounting bolt thread?
I'm in the process of building up a frame and the rear derailleur won't thread on. This is a new one on me; do these things come with different threads? The derailleur is a Shimano 105 and the frame is a Softride.
Of course, my lbs is closed until Monday. I'll be taking it into them then if I can't figure this out.
Any help would be greatly appreciated!
Bob
Of course, my lbs is closed until Monday. I'll be taking it into them then if I can't figure this out.
Any help would be greatly appreciated!
Bob
07-04-08, 08:06 PM
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All of the rear derailleurs and frame dropouts I've ever worked on are threaded M10x1.0 mm.
07-04-08, 10:00 PM
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Try running the derailleur mounting bolt through the hanger from the wrong side. If the starting threads have been buggered, that might be enough to chase them out.
07-05-08, 11:50 AM
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I had the exact same thought last night, so I pulled the wheel and tried it. The bolt failed to engage the threads. I'm going to stop while I'm ahead and let the bike shop handle this one.
07-05-08, 11:58 AM
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Not always, I couldn't get an old Campagnolo Gran Sport RD into my '83 Dawes Galaxy, although an '07 Tiagra worked fine
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07-05-08, 02:18 PM
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I have no idea what Campy used decades ago but they tended to do their own thing and still do.
07-05-08, 08:16 PM
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Campy uses M10x26 which is VERY close to 10x1.0. Close enough that you can, obviously, screw a Campy derailleur into a non-Campy hanger and vice-versa. Anything with a longer run of threads would be a problem.
07-06-08, 01:15 PM
#8
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If the RD won't thread on, you might have a damaged 1st thread on the mounting bolt. Common problem if the derailleur has been dropped. Rounded off threads won't go into the hanger. Inspect the threads carefully under a magnifying glass.
07-06-08, 02:00 PM
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+1. Also, sloppy manufacuturing can leave a burr. You might be able to use a file and remove an offending burr from the treads.
07-06-08, 06:31 PM
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There's also a slight risk to damaging the threads in the dropout hanger. So to test whether you've fixed the problem with bad threads on the derailleur bolt, get a 10x1mm nut from HomeDepot/Lowes/OSH, etc. These are used in lighting fixtures; typically for holding the glass-domes onto the lights. Test the threading with this nut and when it goes on smoothly, you can install the derailleur without worry.
07-09-08, 11:17 AM
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Since the bike shop wouldn't be able to even look at it until next week, I went to the local hardware store and picked up a M10x1.0 tap and solved the problem for $6.79.
Been working the bugs out of the build since then.
Been working the bugs out of the build since then.
