Adapt claw RD to direct mount use?
 

What's the best way to use an RD that has a claw on a frame with a dropout hanger?

Assume the RD doesn't have a captive bolt.

Last time I tried this the hangar bolt wasn't long enough to get through the frame dropout to use the nut from the claw to capture it on the other side.

So...

1) Try to find a longer bolt?
2) Thread the nut onto the bolt first then the bolt to the hanger, using the nut as a jam nut?

Any other ideas?

Maybe I am not understanding the question. If the frame has an integrated hanger... I don't think the nut is needed.

I, too, am confused? What is a captive bolt? Generally, all that is required, when faced with an integral derailleur hanger, is thread the derailleur bolt into the hanger. There is no need for a lock nut like the one included on your hanger bracket.

Of course, as I mentioned, I did not really understand what your concern is. None the less, I do hope that I have been a help.

I think the captive bolt is a part of the derailleur. For example, the Campy Nuovo Record hanger bolt was loose but some of the suntour cyclone hanger bolts were held "captive" in place (with no springs either.)

Here is a picture of a captive hanger bolt:
http://farm3.static.flickr.com/2574/...223_z.jpg?zz=1

Huh? What? Need pic for illustration.

Depends on the derailleur... But, if you remove an originally mounted claw hanger you may also need to add a "stop washer" inserted between the derailleur and the dropout to limit the forward swing of the derailleur.

I just mention this because that sometimes presented problems when attempting to modify some old Simplex Prestige derailleur models which had come factory fitted with Simplex claws.

:( If this is the case, let me know and I'll explain the issues in detail - and with illustrations.

Yes... Photos of your derailleur and mounting bolt would be VERY useful... :innocent:

Using mkeller's pic here...the surface of that locknut extends past the edge of the arm of the RD, so when you cinch it up against the integrated hanger the RD is still free to pivot. If I have a Suntour RD that had a claw...the claw is threaded, so when the hanger bolt is run through it you stop just short of the claw, then the lock nut from the other side sets that "gap" allowing the RD to pivot.

But, If I remove the claw and mount directly to the integrated hanger the RD arm cinches up right against the hangar (since there's nothing to space as in the captive bolt scenario) locking it in place and not allowing it to pivot. In previous attempts the hanger bolt has been too short to go through the integrated hanger (which has always been thicker than the claw) and leave enough threads for good purchase for the locknut on the other side. In this scenario the integrated hanger would "replace" the claw...it's just that the increased thickness of the integrated hanger doesn't leave enough thread on the bolt for a locknut (and I did find some 10mm jam nuts...still not thin enough).

Does that help? Pics tonight if it doesn't.

Well, if the top pivot is unsprung (like almost all SunTour derailleurs, and Campy NR/SR style), then it doesn't really need to pivot - it will change just fine. For these derailleurs, the top pivot is really only used when removing/reinserting the rear wheel. So having it locked into place while riding isn't a problem.

I used an old Raleigh branded Suntour Vx with hanger to replace a 1st gen. Cyclone RD on my friend's Puch. I just removed the hanger, mounted the Vx with a thin washer between the bolt and derailleur hanger and adjusted the screw. Then I adjusted the RD as I would normally and Bob's your uncle. That was my only experience doing this.

Duh, of course, there was the piece missing from my brain. Thanks. If I have to change a wheel I can slightly loosen the hanger bolt.

Yep, and that makes perfect sense now thanks to ctmullins. I was creating an issue where there wasn't one...having the pivot is nice but not necessary.

BTW, need another Raliegh branded RD (and FD)? I saw a pair at the co-op yesterday :)

Nah. Thanks, though.

If I understand the exact problem, tightening the mounting bolt causes the internal jam nut (the one that's within the derailer knuckle and merely protrudes a bit) to tighten and bind the pivot before the bolt is securely tightened into the frame hanger.

Hence, the thin, external lock nut allows for the bolt to be lightly screwed into the frame before securing the nut, and the internal jam nut doesn't get over-tightened (which would prevent the derailer being swung back during wheel change).

One solution to the bolt being too short to allow the lock nut being installed is to LocTite the bolt directly to the frame's hanger, so that heavy torquing isn't required. This should allow the internal jam nut to maintain it's pivot clearance adjustment during the derailer installation.

The better solution is to secure the internal jam nut to it's adjusted clearance position using Red LocTite. This will prevent the pivot from tightening up while you install the derailer with normal torque to the frame's hanger. The Red Loctite, once set, won't let go in a million years w/o heat.
I would add a Thin, lubricated washer or two between the internal jam nut and the hanger so as to allow the nut to turn more freely as the bolt is tightened. The extra slipping surfaces will reduce the torque trying to rotate the internal jam nut out of adjustment even if a lower-spec threadlocker (blue) is used.

This problem would have been avoided if Suntour had just added a shoulder to the bolt which bottomed on the hanger. Clearance could then be adjusted with shims, much like other derailers (even some Suntours) are. Having the mounting bolt pivot freeplay externally adjustable with a locknut isn't necessary, but I suppose the locknut does make up for the fact that the claw hanger, being as thin as it is, has a pretty measly torque rating as far as securing the derailer.

Trick is keeping the bolt retaining nut from tightening as you tighten it onto the frame.

Have you considered just getting another rear derailleur, if you are not asking it to click
with a indexed lever anything with a long cage will work..


Above scheme is OK , unless you let excess LocTite run into the area around the bolt and glue it in place.