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Old 07-20-11, 07:28 PM
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jonwvara 
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Location: Washington County, Vermont, USA
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Bikes: 1966 Dawes Double Blue, 1976 Raleigh Gran Sport, 1975 Raleigh Sprite 27, 1980 Univega Viva Sport, 1971 Gitane Tour de France, 1984 Lotus Classique, 1976 Motobecane Grand Record

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A tale of two VGC Luxes

Here are two VGC-Luxe rear derailleurs, one of which is the older non-captive bolt style (the nice clean one) and the other of which is the newer captive bolt style (the filthy one that has been plundered for spare parts). Interestingly, the date code on the older is UD, while the newer is UF. If I'm interpreting that correctly, one was made in April of 1978, and the other in June of 1978. That would seem to pretty well nail down when Suntour switched over from one style to the other (assuming they made the switch all at once, rather than phasing it in somehow.)

Here's what BF member headset had to say in response to an earlier post of mine asking if the captive-style bolts could be removed:

"I believe 'captive' simply means the bolt is held on the derailleur with a special recessed nut. The 'nut' looks like a thick washer with two recesses in it and to get it off you need a two-pronged recessed nut tool. I made a tool from a short section of pipe that fit the diameter of the nut and ground the end down to create two pins that engaged the recesses. Holding the nut in place you use an allen key from the other side to loosen it.
Suntour did an amazing job with this actually, once you remove the hanger bolt there are very thin shims behind it to fine tune the play in derailler's swing."

Okay, I still haven't had one apart--haven't made the necessary tool--but if I understand that right, the washer with the recesses that holds the bolt captive is cranked presumably down tight against an internal (to the derailleur body) shoulder on the bolt, and a series of thin shims under the bolt head cause the bolt to fit snugly but not tightly in the derailleur body, allowing it to pivot when bolted tight to the dropout hanger so you can remove the wheel. This is the only type of Suntour derailleur I have ever used, though I've used a great many of them.

On the older style, I would have thought that the bolt just extends through the derailleur body and the whole assembly gets rigidly bolted to the hanger. That means you have to loosen the bolt to pivot the derailleur enough to remove the wheel, but that's manageable enough.

What has me confused here is that the non-captive bolt pictured here--which is 11 mm in diameter in the unthreaded portion--has a very short 10 mm shoulder just above the threaded portion. The washer in the photo fits snugly over the shoulder, which extends just beyond the body of the derailleur when the bolt is in place. When the whole thing is screwed tightly into the dropout, the bolt shoulder presses against the washer, which presses against the derailleur hanger, but because the washer is a little thinner than the bolt shoulder, there's a little gap--it may show in one of the photos--between the washer in the derailleur body. That allows the derailleur to pivot, but very sloppily--there's maybe 1/8-1/4" of play at the end of the derailleur cage.

What am I not understanding? Are there supposed to be some shims between the bolt head and the derailleur body to effectively shorten the shoulder? That would effectively shorten the mounting bolt enough to have the shoulder not be in the way anymore, but in that case why does the bolt even HAVE a shoulder? I suppose it could be the wrong bolt, but the head fits the recess in the derailleur perfectly, so I'm guessing that it's the right one.


Attached Images
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PICT0065.jpg (100.6 KB, 15 views)
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PICT0064.jpg (100.5 KB, 11 views)
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bolt2.jpg (99.3 KB, 12 views)
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PICT0066.jpg (86.7 KB, 11 views)
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PICT0067.jpg (84.5 KB, 15 views)
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Last edited by jonwvara; 07-21-11 at 03:23 PM. Reason: kaizen
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