Hi Guys,

So I finally built up the Colnago sprint I got a few months back with what I was hoping was an indexed setup but am now having some issues with it even on friction mode. Here is the setup
FD - none at the moment (Superbe FD otw from auctions)
RD - Suntour Superbe Pro 3100 VeloBase.com - Component: SunTour Superbe Pro
Downtube shifters - Suntour Superbe Pro 6, 7 indexed capable VeloBase.com - Component: SunTour Superbe Pro (6, 7 index) - Ran this setup indexed with DA 7400 7 speed wheelset on another bike previously with no issues.
Wheelset - Dura Ace 7400 7 speed (13.14.15.17.18.19.21)

The issue - Indexing the 7speed works well with the 21t needing to be coaxed if I am in the big ring 53T (no issues on the small 39t). The issue is that putting any power down during climbs or sprints makes the gears jump down to 19t, 18t and eventually down to 15t where it seems more stable. This happens in both big ring and small ring, both indexed and friction (easier to make it jump using big ring under friction shifting). RD seems to struggle to hold everything above 15t. The downtube shifters were not lubricated so I dont think thats the problem.

What have I tried:
Replacing cables - First noticed the issue during my shakedown ride from the bike shop, tried tweaking and then ultimately replacing the brand new cables the bike shop had installed with my own new ones.
Lubricating bottom bracket cable pass through - read that this could be an issue during frame flex although the frame is quite stiff. I first tried to install the inner cable housing (the little plastic white housing when you remove the metal section of shift cables) with lubrication on the bottom bracket bend section where the cable goes. After that did not work, I removed it and used direct cable to steel with some heavy amounts of lube which unfortunately did not solve the problem.
Upper limit screw - made sure to get the upper limit screw set to be able to capture the 21t and then some (more than I would normally) just to make sure that was not causing the problem.
DT shifter screw - made sure this was tight both in indexed and friction mode.

None of t he things I have tried seemed to solve or lessen the problem. I am considering swapping the downtube shifters to either DA 7 speed ones or Suntour accushift but as much as possible would like to use the Superbe one since its the prettiest imo. Any ideas as to why this is happening? Could it be a problem with the RD or the DT shifters maybe?

Check hanger alignment.
Check the sequence and orientation of the shifter assembly.
Check the threads on the cable adjuster both the body and the threaded ferrule.
Check chain line.
Stupid question, does the lever move when it upshifts?
Is there a spring adjustment on the RD

53/21 is cross chaining and shouldn't be done Downshift to 39 sooner.

Have you checked whether or not there is wear on the sprockets? You don't mention whether you are running a freewheel or cassette. Or if a cassette, whether it is UG or HG. This would also be helpful information.

I would remove the sprockets from the freewheel body or disassemble the sprockets on the cassette. Most times, excessive wear is seen first on the spoke side of the sprocket, and with the exception of the largest sprocket, can't be seen unless the sprockets are disassembled. When you do post pictures in order for us to assist in determining.

I agree on the cross chaining part but it also happens with 53x17/18 which I would think should normally be ok to run? Chainline is visually quite straight looking down while riding.

I am using a 7 speed Dura Ace UG. Have not checked it for wear, will post pictures as soon as I can. From what I have read, cassette wear affects indexing performance. Does it also cause ghost shifting issues even on friction?

I'm no expert but I'd still suspect the shifters. Had the same thing going on when I took the Krapf out this weekend for it's first ride. It's friction only Superbe and was ghost shifting in the beginning even though the shifters seemed tight. Cranked the D ring maybe a 16th of a turn more and the problem went away and stayed away for the rest of the ride. Was able to have it hold gear while mashing on some minor climbs even. Not sure how your indexing shifters work but when I had this with a set of my Campagnolo ones it was the wrong G springs in the shifters. What controls tension in your shifters?

Here are some photos of the setup




RD pulleys are practically new. Guy who sold it advertised it as barely used.

Chainline on 17t

This is the nut I tried to adjust to see if it would change spring tension.

Would like to try to sort it out as is. Any input is appreciated

Yea I figured it might be the shifters or the RD. Was leaning towards the RD since I used the exact same setup with a different RD with 0 issues before it was transferred here. That said I only previously used it indexed. Not sure I understand what you mean by what controls tension. Would that not be the attachment bolt with the D ring? I had a quick look when I re-installed the new cable and it seemed like it would be risky to get into the mechanism so I left it as is for the time being. I could try going super tight but I am worried I might strip threads or break something. It is tight to the point of being painful on the thumbs and not moving any further.

If anyone knows a guide to disassembling these shifters it would be appreciated. VeloBase.com - Component: SunTour Superbe Pro (6, 7 index)

Gosh, I don't think that's a matching set. The rd is not of indexing times, and are not accuset, but that is not the issue for all the ghost shifting.

The shifter indexing probably does not match the pull ratio of the rd is one. Another is the shifter is worn and won't hold the tension.

If it was a worn shifter, should I not have experienced the same ghost shifting when I previously ran the same setup (same shifters and all) with a Suntour Sprint RD on another bike?

I’d also suspect the shift lever as the problem. Probably best to disassemble, lube what needs to be lubed, clean what needs to be cleaned and reassemble. I have found ghost shifting almost always is because the d-ring or equivalent isn’t tight enough.

The biggest issue I see is you're not running Suntour 7-speed cogs. You need a Suntour AP freewheel or the very rare Suntour cassette/freehub. Suntour index shifting will work with 6-speed Shimano cogs but 7's have a unique asymmetrical spacing.
If you got this setup working before, I think it was blind luck. Even a bad choice of chain can throw the Accushift setup out of kilter.

Read more here if you haven't already.

Would this have the same effect under friction setup? I intended to run this as a friction setup so I would be able to compare what it is like to ride friction vs STI indexed (DA7400 8 speed which is now on the bike that previously had this). I understand its not a compatible set of parts but was hopeful that maybe it would matter less on a friction setup?

So if I understand correctly - you had these 6/7 speed Superbe Pro shift levers working correctly with a SunTour Sprint RD while running Dura Ace 7speed UniGlide on your previous bike?

And now you are attempting to do a similar setup on the new bike but this time with the older style Superbe RD?

I’m confused if the auto shifting is occurring in both friction and index mode?

If it is auto-shifting into smaller cogs on its own when climbing hills, this suggests that the D-ring is not tight enough. If you have tightened it up as tight as you feel comfortable with then you might need to run a corresponding tap into the shift lever braze on to see if there is some crud on the threads or if can be tapped a bit deeper…

BTW: those 6/7 speed Superbe Pro are some of the prettiest down tube levers ever produced. When run in index mode with a 7 speed SunTour “AP” freewheel or cassette, it should index great.

If no one mentioned it yet, SunTour AP freewheel and cassette spacing is not equal between all the cogs. The smaller cogs (bigger gears) have spacers that are less wide than the rest of them (I think I’ve got that right).

Friction will be perfect IF the shifters and other components are functioning properly.

Auto-shifting to me usually results from too much lube in the shift lever, even if I didn't put any on there.
I don't know those levers, so I can't be sure of that. If they can be cleaned, I would try that, and not add lube.

I have a lot of experience dealing with Suntour Accu-7 setups using different cogs and derailers.

My first question will be if the shifter has been lubricated?

These parts are almost 40 years old, and I have found that the indexing mechanism absolutely requires lubrication (using ordinary oil) in order for the indexing clicks to detent correctly.

Don't take the lever apart, just remove the lever from it's bracket and get some oil inside of it through whatever gaps are found, mainly on the friction-screw side of the shifter barrel assembly.

A good sign is when the freshly lubricated shifter has sharp, loud detent clicks.

I always advise that the cable's path be entirely plastic-lined, for both index and friction setups. I go as far as fitting plastic tubing to any bare-metal bb cable guide, retained by a blob of 5-minute epoxy.

Some of the Accu-7 levers have an indexing selector ring with up to three marked positions, and you don't want anything to do with the F7 setting. Pure friction or pure detent action is preferred. Be sure that the selector ring itself is in it's proper detent (I believe that the friction screw must be slackened to reposition it and to examine it's range of motion).

The only detent position that ever seems to wear out is the one for the largest cog, the result of the lo-limit screw being set too tight over many thousands of frame-flex cycles.

https://www.yellowjersey.org/Suntour21.pdf

I once had a Superbe Pro 7sp drivetrain. I don’t recognize these levers as Superbe Pro and the RD is clearly not Superbe Pro but the first thing I was going to say is that the thumb screw attaching the shifters to the downtube needs to be greased and tightened hard by hand. Otherwise you will experience ghost shifting. My Superbe Pro hubs were freewheel and I recall a Sachs 7 speed freewheel working well.

You still haven't mentioned whether you are running a freewheel or a cassette. And your pictures challenge me to make an educated guess.

Looking at the top picture I was guessing a freewheel, based on the guess that the smallest sprocket sort of looks as if it is threading on with a flange inside the body.

But the second picture clearly shows the spacers, which all appear to be the same size in diameter. If you were running a freewheel, the spacer between the largest sprockets would be larger in diameter. So, I'm now leaning heavily towards it being a UG cassette. Which if it is, provides you with an HG option.

Break out your chain whips and remove the sprockets. Show us the spoke side (no "Index" or tooth count sides). And take a picture of the front of the body where the axel emerges as well.

Sorry but you´re wrong. That is a first generation Superbe Pro RD.

You can can shorten the shifter thumbscrew a little. It might be bottoming out and you think it is tight. It is. But not against the shifter.

hello, which suntour superbe pro has an index for 7 gears?

Yes it was working indexed (never tried it friction previously) on my Zunow. The indexing was not great and needed to be coaxed a bit towards the middle of the cob but it did function reliably. I would now like to run it with this older gen Superbe Pro RD on friction mode. I have never tried friction and would like to compare to my Zunow which currently has 8 speed DA STI. The reason is that cosmetically i prefer the DT look but ergonomically STI is much better. Since I ride these daily, I would like to see if I can live with friction despite the better STI ergo for my Zunow. If not then I will need to buy another bike to run STI on in true N+1 fashion hehe.
Yes the ghost shifting is happening both in friction and indexed. It happens less in indexed but I can still induce an auto shift with about 200m of hard out of the saddle uphill. Under the friction setting, even with medium seated pedalling the RD starts to auto shift in under 100m.

Never lubed it since I read too much might cause slipping. That said the bike shop did the first install so I will ask them if they did. There are loud clicks when indexing but not as loud as my Sprint accushift. It does feel super nice indexed.
The shop did fit inner cable plastic at the sections where the cable runs through the BB cable guides. When testing I thought that might be a problem so I moved further up the cable and away from the bend and it did improve a bit so I will keep it off for the time being.

I was thinking this might be the reason I cant get it tight enough. Will check it out and see what I can do about it. On my ride earlier I tried using a pliers to get it tighter. Got it a teeny bit tighter and the auto shifting took more time but in the end it did still auto shift. At least I feel this is the right direction. Wont touch the RD for now and will focus on Shifters.

I believe its the 1991 Superbe Pro DT shifters VeloBase.com - Component: SunTour Superbe Pro (6, 7 index). They are super pretty imo.
1992 onwards had 7 & 8 speed indexing VeloBase.com - Component: SunTour Superbe Pro (7, 8 index).

That looks like a cassette hub due to the thicker cross-section closest to DS.

The RD is first generation superbe from the 70s, and I wouldn’t expect it to index correctly with the last generation superbe pro accushift index shifters from the late-80s/early-90s. However, the index shifters were compatible with some contemporary sprint RDs. This might be the biggest clue.

Make sure the shifters were assembled correctly, with all washers and spacers in the correct order and orientation. Insufficient ability to tighten might indicate a missing washer. I have the prior generation superbe pro shifters and they have a lot of bits.

Edit: Just saw your post above and yes, friction should be fine with all components there.