The Golden Boy 

That is a pre-indexing, pre-Accushift derailleur made for 5 and 6 speed freewheels. Any indexing you may get out of it is purely coincidental.

Any "modern" indexing shifter (after the advent of SIS) is going to have a cable tension adjuster barrel- if your derailleur doesn't have it, it's not index compatible. Even if you do have an adjuster barrel, it doesn't mean the derailleur is index compatible (Suntour V-GT Luxe). Sprint had two very similar looking derailleurs, one without and one with an adjuster barrel. The one with the adjuster is the Accushift compatible version.

Suntour lost a lawsuit with Shimano about the switching from indexing to friction- so the "friction" settings on most Accushift shifters is just a lighter click- it's not "friction."

Accushift is finicky even when it's set up within it's parameters. Accushift shifters, mated with a corresponding (meaning within it's Accushift series) derailleur with good cables and housing, and a good 6-7-8 speed chain. 6 speed is the most forgiving- the spacing is effectively the same between cogs and the width of the cogs for both SIS and Accushift. Once you get in to 7 and 8 speed territory... I don't go there.

I have set up several bikes with Accushift shifters (Command Shifters, Superbe Pro shifters, SL shifters) and derailleurs (XC Pro, XC Comp Superbe Pro and Sprint) mated with Shimano 6 speed freewheels.

Lots of people can have lots of varying degrees of success mixing and matching different parts in an Accushift system- and what's acceptable to one person is uselessly ****** to another. I'd suggest staying as close inside the Accushift universe as possible.

dddd

My own early Superbe friction derailer seems to effect more in the way of return force on the cable than many other derailers, at least as felt at my Superbe friction levers.

And I'm recalling that I often used tools to heavily tighten my Accushift Command shifter friction screw so as to realize firm indexing retention.

So that particular rear derailer may be less than happily compatible with those levers, unfortunately.

However, I mentioned oiling them, mainly to give crisp indexing, but ALSO so as to dissolve any thickened grease that can defnitely cause any friction shifter to slip slowly due to the high viscosity.
It's the very same as when a handlebar stem quill sometimes tends to slip until the old grease is dissolved or diluted with fresh lube, a layer of slimy old lube just does not allow good grip!


As for the indexing compatibility of old derailers, there are two main issues:

First is the cable-to-cage actuation ratio ("actuation" for short) that needs to be the same. Suntour, Shimano, Simplex, Gipiemme, Campagnolo and Ofmega all shared the same actuation on many of their pre-indexing friction derailers and which was copied exactly when Shimano and Suntour first introduced SIS-style indexed shifters.
Changes in the actuation of SIS derailers came only when Shimano introduced their second (600) indexed gruppo featuring longer cable travel, but their Dura-Ace derailers kept their vintage actuation ratio all the way through the 8s era.
Suntour similarly changed their actuation ratio when their very low-cost 3040 series parts came out, presumably to better deal with lower-quality cabling on the cheaper bikes.

Secondly, index shifting requires close positioning of the top pulley to the freewheel which does not change too much as the different cog and chainring sizes are selected.
So it is often a problem getting vintage friction derailers to index-shift well, especially when modern (i.e. super-flexible) chain is used. This is a bigger problem when wider-range freewheels are used with the old friction derailers, since they were not designed to maintain the chain gap according to the requirements of indexed shifting.
And many of the older friction derailers lack any adjustment of the chain gap or "B-tension" as it is called.

So in order to make friction derailers index, a lot of things have to somewhat occur together, but often this happens by pure dumb luck.

Case in point is when I used a Campagnolo Gran Turismo derailer with 7s Shimano Ultegra SIS levers:
The Ultegra levers are designed for the newer Actuation ratio requiring longer cable travel, so when used with the older friction derailer would index only a wider-spaced six-speed freewheel.
And the chain gap was really excessive, so I had to take the derailer's cage-pivot apart and drill a tiny hole for the end of the spring to wind tighter (the GranTurismo being a dual-sprung derailer so this pulled the body foward and thus pulled the pulley upward).
The derailer also has no cable adjuster, so adjustment is done only at the pinch bolt.

Another example of mixing is when I used Accu-7 Suntour Command levers with a vintage Shimano Titlist rear derailer, which had too much chain gap to reliably index a big 7s freewheel. But I got it to work by stretching (over-stressing, and thus relaxing) the B-tension spring, and which brought the pulley up closer to a smaller Suntour PowerFlo 7s freewheel (and then finally indexed reliably).

Many of the 1980-ish derailers offered by Ofmega, Gipiemme and others were apparently Simplex-built copies of Shimano friction derailers so also actuate just as most Suntour Accushift derailers and Shimano 74xx SIS derailers do. The 740x rear derailers thus also work excellent with most shifters from the Accushift parts family.

Beginning with 600SIS though, Shimano's derailers (which are now most plentiful) were designed for greater cable pull, so their matching SIS levers were updated to move the cable a bit further. So these (non-740x) rear SIS derailers need to have their actuation altered (by moving the cable to the other side of the pinch bolt) in order to work with Shimano 740x or Suntour Accushift levers.

One old friction derailer that will not index is the Huret Allvit, which has an odd, regressive (i.e. non-linear) actuation ratio. No shifter available can handle that.

LeSexyFishorse

7 speed for me with the Sprint accushift indexed perfectly. Almost as good as the 8 speed DA I was running. Switching to the Superbe DT shifters it still worked but needed some coaxing. In both situations I ran a Yaban 7 speed chain, Shimano, KMC X series, decathlon and a few other local cheap bean local brand China chains would make the indexing finicky on both shifters.

So I think I might have fixed it. While messing around with the DT shifter and trying to screw it in as tight as possible I thought I would go through settings once again just to see if it might change something. I remembered what you said about the lawsuit and it just being a "lighter click". I remembered noticing that there were very light bumps when I first set it to be 7s friction. The bumps were not as pronounced as in the indexed setting so much so that you forget them when you are actually riding but they are ever so slightly there. I noticed the same very light bumps under 6s friction setting. Crucially I noticed that when transitioning between the 7s index and friction setting cluster to the 6 speed index and friction cluster the shifter gets quite tight as it feels like there is a ridge separating both clusters inside. The 7 and 6 speed clusters feel "recessed" including the friction setting with the screw having more slack when in the clusters and the space in between them elevated with the same screw having much less slack. I have not taken apart the shifter so I dont know if it is an actual ridge but I figured if enough friction was the issue why not put the setting on that ridge and try it out. Glad I did because I was about to disassemble the shifter completely and start messing with the RD if it didnt work. So far that setting seems to work perfectly. I have not even needed to use pliers to tighten down the screw. Went for a 1 hour ride with about 2km of steepish climbs which I did several times both seated with power and out of the saddle with the chain crossed horribly with no issues at all. Added a little diagram of what I mean below, please forgive the 5 year old writing. My question to those who have taken this type of DT shifter apart is will this break something internally in the long run? Will do more testing over the week.
P.S. I love friction shifting .

The Golden Boy 

The internal of the shifter is a snap ring holding in a ball bearing that rolls on a plate with detents for each index. I'd guess you're kind of between the detents on either side of the plate.

The plate looks sort of like this:

IMG_0063 by Dave The Golden Boy, on Flickr

LeSexyFishorse

Thats cool! so I guess if im in between its cable on alloy or steel so it should be ok? Think it might mark the ring over time? Im guessing even if it does there should be no performance effect since its not essential for indexing?

The Golden Boy 

There's some great pix of some well used Accushift shifters on Naoki's blog:

https://commandshifter.blogspot.com

Senrab62 

I've read through this, as a potential point of reference, but am I correct in understanding that the OP is using a friction derailleur for indexed shifting?

The Golden Boy 

That's how I interpret it.

Keep in mind, despite different pull ratios and cable adjusters, methods of cable attachment and the myriad of differences and tolerances between indexing systems and old friction systems- sometimes you can get things to work that shouldn't work. But as a general rule don't expect things to work out of their intended systems. If they do work- it's coincidental. I've heard of people getting V-GT Luxes to index... It was never intended, it wasn't engineered for it... but some people, apparently, got it to work.

Additionally to that, people have gotten mix-n-match systems to work "good enough" for them. Maybe 5 out of 7 gears worked reliably... but that was good enough. For them.

On the other hand... Accushift is finicky to begin with. Some people disparage Accushift/Suntour because it really doesn't work well out of its intended universe. I remember a guy had a really cool bike, and he had some sort of Accushift shifters- and talked about how terrible they were... but he was using a Shimano MTB derailleur... and didn't feel he had to change the derailleur for the shifters to work- they were just garbage.

I've played around with bunches of old systems, trying out other people's hacks- I had some 6 speed Dura Ace Shifters pulling a Suntour XC Comp derailleur on a 5 speed Suntour Perfect freewheel- I swear that setup indexed perfectly. I don't know if it would on any other bike- but I ran that for about a year. But I just stayed into Accushift 6 speed and SIS. Closest I come to crossing the streams now is using the 10 speed indexing plate on Accushift shifters. (I should buy a few more of those things...)

Senrab62 

I appreciate the thorough reply. I, am not, going to be using indexing at all (superbe pro friction) but have been researching everything suntour in preparation.

LeSexyFishorse

For this bike I intend to run as a friction setup. I did however run it indexed despite it being a friction RD with no issues other than the some sloppy shifting. This was during the shakedown runs when I was trying to isolate the slipping issue. As has been mentioned however, this setup is finicky due to not being designed for it. I likely just got lucky. For your reference the indexed setup was:
Suntour RD VeloBase.com - Component: SunTour Superbe Pro
Suntour Superbe Pro DT shifters 6,7 indexed VeloBase.com - Component: SunTour Superbe Pro (6, 7 index)
Superbe Pro 53T and crank VeloBase.com - Component: SunTour CW-5000, Superbe Pro
Yaban SLA 7 speed SLA/SLA-H8-YABAN CHAIN INDUSTRIAL CO., LTD. (marked as 8 speed but was sold by a local shop with 6,7,8s packaging prob older version)
Uniglide Dura Ace 7 speed cluster on DA 7400 hubs VeloBase.com - Component: Shimano MF-7400, Dura-Ace (7sp). If I remember correctly, HG 8 speed cluster greatly improved indexing as well.

In case you ever decide to try it.

I must say I'm loving friction very much. Outside of going all out or in maybe a race scenario, the ergo tradeoff of DT is not so bad imo. I thought I would not like it once I tried STI but figured I would compare them side by side anyway to be sure and I'm glad I did. Theres a 5% climb into a downhill section into a flat 400m section towards the end of my ride that begs you to sprint. Picking up speed downhill and Slamming the DT shifter all the way into the hardest gear after suffering from the climb and going into an all out sprint to finish my ride is incredibly satisfying. Kinda like top gun throttle scenes or maybe thats just me haha.

Thank you everyone who provided their input. Im glad I was able to sort this out and not have to never try friction properly.