RD Identification
 

Greetings All,
Can someone ID this rear derailleur? The bike is a 1985 Fuji Touring IV. I’m not the original owner and other parts have been replaced/upgraded. Thanks for your help!
Robert
https://cimg4.ibsrv.net/gimg/bikefor...f993e40a8.jpeg
https://cimg5.ibsrv.net/gimg/bikefor...0622cf300.jpeg
https://cimg7.ibsrv.net/gimg/bikefor...2bef65d12.jpeg

My first thought was Shimano STX (mtb) https://www.ebay.com/usr/kycho-8 - Pinch bolt is wrong & it is a MTB derailleur
https://cimg2.ibsrv.net/gimg/bikefor...f5b7a93aed.jpg

Took a guess that RSX (road derailleur) would be similar, looks like a good match.
https://www.ebay.com/itm/276094694537
https://cimg0.ibsrv.net/gimg/bikefor...649d005f69.jpg

Many Thanks!

Suggestions for an upgraded indexed RD? The bike has 14-34 6 gear cassette with a triple FD , 48-24.setup currently. Thanks!

Your RD is compatible with indexing. Indexing is done in the shifter. Shimano still makes 6 speed shifters.

If you still want to replace the RD, any long cage (SGS) derailleur will work as long as it's 6 7 8 9 and road 10 speed, and doesn't say Dyna-Sys or Linkglide. You still need a 6 speed shifter for a 6 speed freewheel or a 7 or 8 speed shifter for a 7 speed freewheel

Lets see a pic of the whole bike, what is on there now?

That is a pretty big total capacity and maximum cog size. The only one that I know of, which is silver, is the Deore XT RD-M761 SGS

Shimano Altus comes in silver:

https://www.modernbike.com/product-2...hoCxgsQAvD_BwE

For what it's worth, Grant Peterson likes 'em:

The best-designed cheap rear derailer in existence.

https://www.rivbike.com/products/shi...tspdOuUAt1gtEA

That’s the RD A 415 I believe ( 8 speed) so you COULD put up to an 8 speed cassette if you so desired (with the right hub).

One of the best cheap groups. In some ways I liked the RSX and RX100s better than the 105…

What shifter do you have, or plan to use? Are you currently index shifting?

The shifter determines indexing and would affect the rear derailleur selection. Do you plan to keep the current freewheel?

The current routing in the OP pics looks very unusual, as if the actuation ratio of the RD is being increased. Stock routing for this RD (Position A in the pic below) should be about 1.7/1. The pictured routing is similar to the way some RDs can be used in a manner that emulates a higher actuation ratio RD, (see below), only this is more extreme.

Routing at Position B is used to get a higher actuation ratio that is similar to older Dura ace (aprox. 1.9/1).

See Sheldon Brown's Dura-ace page for details.


https://cimg1.ibsrv.net/gimg/bikefor...5550aa9a9b.jpg

Shimano Deore MT-60 would do the job nicely.

Bike photos
 

Thanks for the helpful information. The bike currently has Suntur index shifters. The double crank is well used and I have a Sugino AT 48.36.26 that I can use to replace the double.
Here are some photos of the bike.
https://cimg5.ibsrv.net/gimg/bikefor...625487d37.jpeg
https://cimg8.ibsrv.net/gimg/bikefor...8d53bd640.jpeg
https://cimg9.ibsrv.net/gimg/bikefor...dee5d36c3.jpeg

Are those shifters indexed? If it is, does it currently index correctly? Or are you changing shifters?

The original Suntour Accushift indexing system was different from Shimano. Don't know if later Suntour indexing were different from early versions.

To find the correct rear derailleur to work with your shifter, specify what shifter will be used.

Those are not indexed shifters.

If you like the friction bar end shifters, stick with them and run 3 x 7 gearing. If you want indexing, put up a WTB for the shimano 7 speed bar ends. If you're not happy with the suntour bar ends you are running, the dia compe eno bar end shifters are fantastic. I'm running them on my 1982 Trek 720.

Thanks for the clarification on the shifters! I’m looking to upgrade the RD that can be used with the current friction shifters.

It's likely any RD, probably 8 speed and under will work with those shifters but they are unusual, they appear to have Cyclone era levers fitted into Diacompe Silver end pods? I assume there's no ratcheting mechanism in them. You'll need at least a med to long cage to reach the Mega Range freewheel.
You could easily upgrade that very fine frame to 7 speed indexed or not. I think it's a 126 rear spread. 8 speed generally requires 130 mm. Or ride it as it is.

It is definitely an odd conglomeration of parts…double Tricolor CS, short cage RSX 8 speed RD, re-done bar ends. I think they might be ratchet shifters which sort of sound like indexing (micro indexing).

Fuji predominantly sourced SunTour during the friction era.

Is the FD a Mountech or ARx? Hard to see, but either would handle your triple with aplomb.

Get a triple BB, a SunTour Arx or Mountech or Cyclone (long cage), and you are set and it would be very much similar to how it might have been set up originally without much outlay.

Do you have a picture of the rear hub, and cassette/freewheel area? Curious as to what hubs you have.

The Hubs are Sansin Gyro- Master. I bought the bike from a guy who was sharing work space at the local co-op, so we were scavenging parts which explains some the non original parts. The FD is a Mountech, maybe original.

I’m thinking an upgraded RD and ride it.

It’s wonderful to get all the advice from those with more experience. Thanks for sharing!
https://cimg9.ibsrv.net/gimg/bikefor...79247bcf9.jpeg
https://cimg0.ibsrv.net/gimg/bikefor...49e0fdfad.jpeg

Checking my parts box I found a Suntour V-GTluxe in good condition. Any problem using it?

Suntour Cyclone GT is always the answer. If you want to match your front derailleur, then you could do a mountech. For this era of bike and those shifters, I'd do Cyclone all the way.

Suntour V-GTLuxe is excellent. Bombproof and as good as anything else before indexing.

OK, so as expected, this is not an indexed setup.

The V-GTlux could work, but the total capacity may be somewhat 'short'. This would mean that with the proper length chain, the small ring & small sprockets combos would have 'slack'. Not really a problem if this ratio is a duplicate.

Suntour made 34t freewheel cogs back when, so I'd bet at least a sixer that your VG-T Luxe and your Shimano MegaRange will play nice. And Fujis had long RD hangers, or at least my '85 League does. (1980 Superbe clears a 26 with room to spare, and I bert I could get a 28 in there. Spec is 23t max. It shifts better than I do.)

I'd be very surprised if it didn't Just Work (tm).

--Shannon

The largest sprocket may not be the problem. As stated, the total capacity is what may be 'short'.