DogsBody

Don't have the model number yet; but I have a question:
It is obvious that the rear derailleur has a hole for mounting something in it just behind the ?dropout? (where the derailleur hooks onto the axle).
I assume this is for anchoring the derailleur in the proper position; but the frame that it is on has no provision for a bolt.
IS a anchoring bolt (or whatever the method/hardware might be) absolutely required?
Or does simply ensuring the axle nut is tight take care of it?
*Edit*
This image shows a very similar derailleur.
The hole that I am talking about is where you can see the phillips-head just behind the ?dropout? in the upper right of the pic.
-Looks like there is a shaped ?dropout-anchoring plate? bolted there.
Is that little fitting neccessary for installation?

Steev

The piece that the Philips head screw retains sits in the end of the drop-out and keeps the derailleur in position while the wheel is out of the frame. How come the derailleur you pictured is backwards to the standard part? Is it for a left side drive system?

Sixty Fiver

This derailer has a removable hangar which is used on bikes with no attached hangar... and it is backwards.

If your bike has a derailer hangar you can remove this... if you need to use it it will have to be reversed.

Bianchigirll 

is it really on backwards or does it go on a bike with track dropouts? look at the little tab on the bottom of the right side of the hanger

DogsBody

heh. Either the image is reversed, or it is made on mars.
I used that image to show the "bit" I was curious about; sorry for THAT reference cross-up.
Here is better image to reference.

The part I'm curious about is where the hex bolt with the flat-head screw driver slot is just behind the axle nut.
The basic question (redux) is; Is that positioning piece required for proper set-up? Or can one just ensure that the derailleur is retained by the axle nut alone?
-The bike in question has what appears to be NO allowance for the "shaped" piece (that would normally be bolted via the hole in question) that would sit at the back of the frame dropout.
The wheel mounts right at the back of the frame dropouts when installed (or so it appears).
Excuse my lack of knowledge in this area; trying to figure out if the derailleur needs that piece or not, and am a little befuddled.

Sixty Fiver

The little screw and shaped nut is an anti rotation device... the wheel should not go all the way to the back of the dropout as that shaped nut should slide in behind the axle.

There are a few sizes of screws and nuts to fit different width dropouts so my wag is you have the wrong one although things look okay in that pic.

The VX is an excellent derailer btw.

JanMM

Reversing the image still looks not right.

Dan Burkhart 

I think the image was photoshopped together with a reversed image of the hanger.

Jeff Wills

Some derailleur "claws" were made that way so you could put a derailleur on a bike with rear-facing "dropouts". This was necessary in the early days of mountain bikes when people were adapting large-wheel BMX bikes for multiple gears.

Bianchigirll 

I think what you are asking about is the little anchor nut in this image. check your bikeshop they should have one. you may have to buy the whole hanger but $3 isn't bad. it holds the derailuer in place when you take the wheel off. sometimes bikes had something on the other side too as an aid to center the wheel.

https://www.ebikestop.com/index_derai...ble-DP1071.php

JohnDThompson 

It's really on backwards. Even on track dropouts, the "angle of the dangle" would be all wrong as pictured.

DogsBody

Right looks image not? lol
Scrambling reference for I was.
Image first available i grabbed.
Okay. Gotcha.
Yes those Suntour VX's are wonderful little systems: I have tuned them before, just never done a full reassembly of a Bike with one that was in pieces before I got my hands on it...
Learning the ways of cycle ninja is not as easy as the Layman might think.

Jeff Wills

Nope. Look at the picture again. The claw is integral with the derailleur, not an add-on like most derailleurs. In other words, this derailleur won't work on a frame with a built-in hanger! Also not that there's a stop on the forward edge of the "claw", which prevent's the derailleur from rotating forward. If the claw were reversed, that stop would either get in the way or be useless.

mcgreivey

I've seen pictures of ST derailleurs with these backwards claws. If I recall, some bikes for the domestic Japanese market had rear-facing dropouts. SunTour's open side-plate cage design meant this was not a problem.

DannoXYZ 

If you look carefully at the upper-pivot bolt that screws into the claw-hanger, you will see that a 6mm allen-key will fit right in. Hold the nut on the back with an adjustable-wrench. Unscrew the pivot-bolt from the claw, flip the claw around so that the opening faces to the right, and re-screw the upper pivot bolt back in. This diagram is actually 1-generation older than the picture the OP posted:


The little hex-bolt on the claw with phillips-screwdriver opening holds a semi-circular nut on the back with a flanged inner surface. This flanged nut slides into the 10mm slot of the dropout perfectly. Once the entire assembly is slid to the far back of the dropout, you tighten that little bolt to hold the claw in place on the dropouts. This bolt+flanged nut prevents the claw from pivoting so the opening stays aligned with the dropout slot for easy wheel installation and removal.

Here's some pictures of what the claw looks like on the back side with the flanged nut.

And what it looks like mounted by itself. Things make a lot more sense when you see it separated from the derailleur:


It may not be obvious, but if you attached a derailleur to this claw, it would sit 5mm too far outwards. You may also notice on the Suntour claw, that the part where the derailleur's upper-pivot bolt attaches is curved outwards? This clearly indicates that the claw is backwards. In the proper-orientation, this little bend goes inwards and compensates for the thickness of the claw by moving the derailleur in towards the sprockets. With it in the bent-in position, it will place the derailleur inwards in the exact location as if it had been bolted into a dropout with integral derailleur-hanger.

On the opposite dropout, you can get a similar semi-circular flanged-nut with bolt to clamp into the dropout slot to act as an axle-stop. This way, you can just slide the axle all the way back until it stops on both sides and the wheel will be centered between the chainstays.

canopus 

The picture the OP posted is not backwards and is normal for bikes (as others have stated here) that have rear facing dropouts such as bmx and cruiser bikes from that time frame.

It is the wrong part for the application if this is going on a 10/12 speed frame like in the pictures that DannoXYZ posted.

Sixty Fiver

Danno - As always, thanks for the excellent explanation and the time you took to put up such excellent pics and diagrams.

I am aware of the reverse clawed derailers but have never seen one in person as I think these were limited to domestic distribution and there are some odd little derailers that were only made for children's bikes in Japan.

DannoXYZ 

I think it's the same derailleurs. They had different claws to fit different applications. When bikes with integrated hangers became more popular, I was always delighted that the Suntour derailleurs could be unbolted from their claw-hangers and bolted directly to the bikes. Not quite so easy with some of the other brands.

Sixty Fiver

Suntour derailers were always brilliant in their design... even the low end model like the Honour was a very reliable unit although it's weight kept it off any racier machines.

But then we have our Cyclones and Superbes for that...

DannoXYZ 

Don't know if we answered your question. But the frame's dropout doesn't NOT need to have any special fittings for the claw-hanger. The little flanged-nut and hex-bolt actually doesn't bolt into the dropout. It just sits at the end of the dropout-slot. The wheel would then slide into the slot on the claw-hanger and sit about 10mm further foward than the actual end of the dropout slot. You can get a matching bolt+flanged nut for the left dropout to stop the axle on that side at the same location.

DogsBody

Thanks all for the great input.
I have sorted it out.
Funny part of this is that when we got this bike originally this derailleur was on it.
As it turns out someone messed-up big time: The cage was a short, and the system needed long (So this semi-novice was a little confused for a couple of days).
I have since installed a an older Shimano deore derailleur w/long cage, and now have a beauty Suntour for another build in the future.
Once again thanks for all help!!
PS. I'm working on my terminology to aid me in being less of a putz in explanations: Onward, and upward!!

DannoXYZ 

BTW, I'm looking for one of those reversed claw-hangers if anyone has one. Otherwise, I'll just make one... or two or three if anyone wants one.