Senior Ryder 00 

Hi folks,
I’ve changed all of my vintage bikes to indexing FWs & chains for improved shifting,but use Suntour barons.
I recently got a set of Shimano indexing bar end shifters & was wondering if they would work with Suntour Cyclone or Vx derailleurs in the indexing mode? The shifters are labeled “ Not compatible with DuraAce”.
Has anyone had any experience &/or success with this combo?
Thanks & regards,
Van

steelbikeguy

Optimism is a wonderful thing, but these SunTour derailleurs were designed without any thoughts at all for indexing, much less indexing in accordance with another manufacturer's specs.
Maybe you'll get lucky??
Only one way to find out!

Steve in Peoria
(but the Cyclone does work wonderfully in friction mode, and those Shimano bar ends probably have a friction mode setting)

seypat

You might have some luck if you make a Suntour version of Shimano's Centeron g-pulley. I think that is the real key to indexing success.

denaffen

They'll work fine. The indexing comes at the lever, not the derailleur. The only concern is if the "throw" -- the amount of travel for a given gear change -- matches, which is why Dura-Ace won't work. It's a different throw.

I'm currently running micro-shift indexed 10-speed bar-ends, a Suntour Lepree front derailleur and a first-gen Deore rear derailleur and it all shifts very nicely. The indexing works perfectly.

dedhed

Suntour indexing compatibility

philbob57

I was not able to get reliable (enough) shifting from my Suntour V-GT or 1st gen Cyclone GT for 7 speed SIS shifting. There was more than enough adjustment range to cover the 7 speed freewheel width, and friction shifting was fine, but at least 20% of the indexed shifts in the middle of my 14-28 freewheel were problematic.

Pompiere

Not bar-ends, but I have used Shimano 7 speed index down tube levers with a Sun Tour derailleur. I think it was an Honor model.

top506

This.
I got good indexing with Shimano DT shifters, V Luxe short cage, and a Sun Race 13-25 7 block.

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elcraft

This seems to me at least, the heart of the issue. The Centeron Pulley idea allows enough literal “wiggle” room for the indexing to work. But the bolt diameters that secure each brand’s jockey pulley are different. IIRC, the Sumtour jockey pulley securing bolt is thinner than Shimano’s. If some enterprising machinist oriented enthusiast were to fabricate an adapter sleeve and matching Sliding Centeron Pulley, that would permit the use of the Centeron pulley inside a Suntour pulley cage, this would be possible! The GT version of the first gen Cyclone has the jockey pulley concentric with the lower sprung pivot. The short arm version (non GT) has the sprung pivot attached to the cage in another place; not concentric to the pivot. The key would be to not having to change the bolt!
One must assume, that the shifter mech and cassette/freewheel combo would be need to be Shimano for consistent spacing. The tooth design on the Shimano cogs is worth it, anyway. For those of us who still admire and love the Suntour mechs, this would be very worth it!

masi61

I see where you are headed with trying to get a Centeron upper pulley for an improvised “accushift” indexed setup. I still think this would be a crap shoot because the “swing” of the (pre-Accushift) RD may not resemble the swing of a Shimano S.I.S. RD. It is a worth a try though. Perhaps you will get lucky.

My XC Pro RD Suntour Accushift bike is set up to index an 8 speed SunTour Accushift cassette perfectly. The thing is, SunTour solved indexing without a floating upper pulley so the clicks are harder, and not Shimano soft.

70sSanO

Everything comes down to two things, the actuation ratio of the Suntour RD's and if that ratio is consistent from high to low cogs. Actuation ratio is merely the amount the RD moves for a set amount of cable pull; generally per 1mm. Older Shimano SIS was 1.7mm for 1mm of cable pull. From there it is just a math exercise as to whether it will work or not. But without that Suntour ratio it is just a trial and error guess.

The other piece is alternate cable routing. Sheldon Brown has described it for use with older Dura Ace, but there is about a 10% actuation ratio change that can be used in an application where your mix-n-match is close enough. The alternate routing just modifies the attach point and I imagine it could be pushed beyond that if someone was so inclined.
https://www.sheldonbrown.com/drivetrain-mixing.shtml

The Centeron floating guide pulley helps to take up a bit of mismatch/slop. If you can find an old Bullseye RD pulley, you can probably make it work.

If you can somehow go through enough cable routing gyrations and guide wheel mods to get it to work, the last thing you'll want to do is loosen everything up to adjust the cable tension after things have settled in.

Jagwire sells Direct Adjusters that are designed to go into external style STI shifters. I have used them on RD's that do not have a barrel adjuster. I don't know it they will work on a Suntour RD, but they are designed to fit in the same opening as the cable housing ferrule, so I would hope it will work.
https://jagwire.com/products/small-p...rect-adjusters

At this point I would hope you have stopped reading and started looking, probably on eBay, for an 80's Shimano SIS RD and abandoned the Shimano-Suntour indexing pipe dream. If not, good luck with your endeavor.

John

dddd

The old Suntour derailer will not maintain a close proximity between the top pulley and the freewheel cogs since it was designed with a much stiffer bushed chain in mind.
Even a narrow Sedisport bushingless chain is much stiffer than any modern chain.

A Centeron floating pulley won't help at all, because the main issue will be unresponsive shifting. A floating pulley can only make this worse.

The Suntour derailer (both early and Accushift models, 3xxx series excepted) moves a good bit further in response to any given cable movement distance than a Shimano SIS derailer.
The pre-9s Dura-Ace rear derailers move further just like the Suntour derailers though, so compatibility between Suntour and Shimano is much better with those D-A shifters and derailers. The chain gap issue is still going to be there with the Suntour pre-index derailers however.
Yes, some derailers can be "wired" for a longer throw using less cable movement, by moving the cable to the other side of the pinch bolt.
And in some cases one can reduce the derailer's movement by routing the cable further out along the arm at the pinch bolt ("hubbub" method). The derailer below was modified as such by adding a custom-made tab-washer so as to allow a standard 6s SIS lever to work on a narrow-spaced 6s freewheel (arm made effectively longer):



Some "kluge" setups will be made or broken by the quality of the cabling (shorter runs using polymer lining at all cable contact points really helps!).

Senior Ryder 00 

Yikes,
What was I thinking? You have given me lots of food for thought.
Thanks,
Van

Chuckk

What we used to do when everybody was trying indexing on non-index equipment was to align the setup in the middle gear.
So for instance, on a 7 speed, you aligned everything in 4th.
That meant that any misalignment was only half in either direction and they usually worked.

Easiest to do if you threaded an adjuster into the rear derailleur, but if you were careful you could just set it up right on the rd cable clamp.

hypercycle

so what is the suntour Vx RD's typical actuation ratio ?

clubman 

I'm not sure that's well documented since it was never designed to index. In friction, the actuation is pretty much moot imo. You'd have to set up a little experiment to map the amount of cable pull to the gears lateral movement and test it across the full range of motion for a given gear shifter. Other shifters will have different results.

dddd

Most friction derailers including Shimano and Suntour, even Campy (!) have the higher actuation common to the pre-9s Dura-Ace SIS derailers, roughly 1.9 vs. 1.7, so will index accurately (if perhaps shifting not so well) either by 1) using Dura-Ace SIS shift levers or 2) using a freewheel having six speeds together with a seven-speed non-Dura-Ace Shimano shift lever.

The Huret Allvit is an exception to other friction rear derailers in that it's actuation is highly regressive going toward the largest cog. It will not work with any indexing levers.

I found that a Campy Gran Turismo indexed well (though didn't shift so well) using a 7-speed SIS lever with a standard six-speed freewheel. The same thing as with Shimano and Suntour friction derailers that I've tested..

wrk101

The problem with asking others, is good to one person is mediocre to another. I have mixed Suntour friction with Shimano freewheel and a wide variety of shifters. Can't really recommend what I have done, but it does kind of sort of work.

In the end, just do it, ride it for a while, and decide if it meets your requirements.

squirtdad

that is not correct as general statement, different deraillers move different amounts, based on the amount of cable is pulled by the shifter. Sram deraillers and shifters pull differently than shimano, shimano has had variations over the years.

correct is that indexing will work if the pull from the shifter, moves the derailler the correct distance matching distance between the rear cogs.

dddd

True, having accurate indexing motion is a different thing than having responsive shifting.

The difference seems to come down to how well that the vintage derailer keeps the chain gap between pulley and cog small enough so as to effect shifting response using typical modern (i.e. flexible) chain.
The vintage friction derrailers were designed before truly flexible modern chains were created, as even the Sedisport bushingless chain was/is far stiffer laterally than any modern chains available today.

Vintage derailers may lack any b-tension screw needed for adjusting the chain gap, and vintage Suntour derailers having a B-screw still may have excessive chain gap with the screw removed entirely!
Vintage Simplex derailers usually feature a cage-spring tension adjuster nut that can be loosened to change the spring tension then re-tightened, this alters the spring tension balance between the mounting pivot spring and the cage pivot spring so as to adjust the chain gap.
Suntour friction derailers can have the chain gap further reduced (after removing the b-screw) by carving a bit of metal from the screw boss, for more-responsive shifting in both directions.
Dual-sprung-pivot friction derailers like Shimano, Simplex and the Gran Turismo(!) can have their spring tension balance altered by means of drilling new hole locations for the end of the cage pivot spring, as shown below. Changing one spring's tension alters the chain gap just as if the derailer had a b-tension screw!

Lastly, good shifting performance, whether indexed or friction, also depends heavily on best cabling performance, with all cable paths lined with plastic noodle (even at the bb cable guide), and with all flexible housing junctions made not to move around in response to shift lever movement.

One more and final thing that helps the shifting response of typically lazy-shifting friction derailers would be using only a non-floating top pulley (and making sure that the pulley bushing and teeth are not heavily worn). Pulley float is NOT needed or desired when a typical old friction derailer already suffers from an excess of chain gap!

hypercycle

Thanks 'dddd' for the detailed and very informative post!

In the particular application I'm working with: a Suntour V GT Luxe with a bolt on hanger & on a 13-30 7 speed cassette with indexed sram 7 speed grip shifter (I am limited by end user's current preferences wrt wheel/cassette, deraileur & shifter comb), I have it 'working' in all gears, but of course the shifting is 'sluggish or lazy';

After implementing some of your suggestions, shifting is much improved, more or less acceptable, but depending how I have it adjusted, this improvement is currently only in one direction: ie) works pretty good in either the down shifting or up shifting direction depending on cable tension and b screw position. I have not yet removed any boss material from the B screw adjustment and some b screw extension currently remains to retain chain tension when on cog 13 and the small chain ring at crank; as yet I am hesitant to shorten the chain any further and probably have currently about 1.5 to 2 cm between pulley and rear cogs at best.

How tight or short can I make the chain before other issues develop, and will further reduction of chain gap via described derailleur modification b adjustment help gear shifting become more adequate in both directions?

I also realize that some further improvements in cable performance could probably also be made: but does a larger cable/housing loop at the rear derailleur and using the 'Straight Wire' shimano cable housing instead of coiled wire gear housing make enough difference that I should re-cable the shifter with the then needed longer gear cable?

I can't send photo yet since I don't have the needed 10 prior posts; and YES I know that even the crapiest modern shimano or sram rear derailleur would probably shift better, but my friend is 'in love' with his Raleigh branded derailleur and the shimano freebody cassette wheelset using grip shifters on his old Raleigh Super Grand Prix.

Thanks, Pete

top506

Replacing the coiled wire housing with proper shift cable housing with a good loop will most likely solve the issue.
I ran a V Luxe with Shimano A-400 DT shifters and a 13-25 SunRace freewheel and got perfect indexing.

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