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Old 02-17-12, 08:54 AM   #1
himespau 
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mounting a derailleur adapter claw

So I have a couple of old frames I'd like to hang more modern rear derailleurs on. One bike I just got the frame, which lacks a derailleur hanger, and the other has a cheap RD that has a claw as part of it. I went to the LBS and asked for adapter claws. At first they didn't know what I was talking about but eventually dug some out of a drawer (after telling me I should just go buy another cheap RD instead because it'd come with one as part of it). So when I got home, I realized they didn't give me the bolts that you use to keep them in the dropout.

Are these a standard size that I can pick up at a hardware store (along with a washer and a nut to keep in place), or are they something special for this part? I thought I read something somewhere about the nut being special to fit into the dropout partially? Though I could have dreamed that.
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Old 02-17-12, 09:09 AM   #2
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The original part is special. The screw is normal enough but it is threaded into a very specifically shaped gadget. First there's a D-shaped portion of the part that fits inside the dropout, with the length of the D preventing it from turning with the screw. This D sits flat against a backing plate or a flange, which overlaps the inside face of the dropout.

The good news is that the only thing that part does is to hold the derailer in place with the wheel off the bike. If you're OK with positioning the derailer by hand before cranking down on the wheel nut or q/r - you'll do just fine without it.

OTOH I can't see anything stopping you from assembling your own positioning bracket out of whatever.
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Old 02-17-12, 09:31 AM   #3
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On the other hand, it looks like through sheldon's site that Harris is selling adaptor claws for $4 and they're only like a 20 mile round trip away. Maybe one nice saturday I'll just ride down there and see if I can get claws from them that come with the back bit. Or maybe I'll go back to the lbs I got these claws from and see if they have the d-shaped bit and backing plate you mention (though I doubt it) as I'm going back there anyway to get them to cold set one of the frames I want to use.
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Old 02-17-12, 08:08 PM   #4
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Yeah, get the right claw or claw backing nut. Last time I did one, the chain rubbed the claw nut; I just moved a 1mm washer from the left to the right and that fixed it nicely. That wasn't enough to mess up the centering, fortunately.
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Old 02-17-12, 11:46 PM   #5
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Quote:
Originally Posted by himespau View Post
Are these a standard size that I can pick up at a hardware store (along with a washer and a nut to keep in place), or are they something special for this part? I thought I read something somewhere about the nut being special to fit into the dropout partially? Though I could have dreamed that.
Yes, the nut is special, but I suppose you could finagle something to fit. It should end up looking something like this:
http://harriscyclery.net/itemdetails.cfm?ID=963
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Old 02-18-12, 07:56 AM   #6
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Yeah, an adapter claw is basically a generic derailleur hanger and should come with the hex bolt and shoulder nut included.

Shimano still makes a couple models of Tourney RD's with integrated claws and your LBS may have older models as well. None of them are particularly expensive but any would be perfect for city bikes. What did you have in mind that you didn't want to go that route?
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Old 02-18-12, 09:25 AM   #7
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Well, I'm going with two bikes. One is the old fuji mixte I'm building up to make a city bike. That one, a member here sold me an 8 speed Deore LX set of shifters and FD and RD and I just needed a hanger for it. I knew what the front looked like but didn't know what the back side was supposed to look like so I didn't think about it until I got home. The other bike is my main bike that started off as a low end lbs mtb that I've put drop bars on and have turned into a commuter. I don't know if it came with tourney parts or if the guy I bought it from on CL put them on, but I'm tired of having to adjust the RD, so I wanted to put something higher end on that too. Will probably just buy them again from Harris or someone who knows what they are and figure the $10 or whatever the first lbs charged me for them was a learning experience.
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