bikemig 

So I made the switch from suntour friction to shimano indexing--with a brief dalliance with sachs which is shimano compatible--back in the day. I know nothing--in the immortal words of Sergeant Schultz--about suntour indexing.

Is there a webpage that can help me out? I've poked around a bit without too much luck.

My basic question is this: a 6 speed suntour indexing freewheel comes in only one flavor right? If it's a suntour 6 and it's designed for indexing, that's all I need to know, right?

My recollection is that there wasn't more than one flavor of suntour indexing but I could be wrong on this and I only used it on one bike (a mtb).

Also how do I know whether a suntour freewheel is indexing? Is that what suntour called accushift? Aren't suntour alpha freewheels indexing?

Calling on @The Golden Boy who is our resident lover of all things suntour and anyone else who can help me.

The Golden Boy 

I only know what I've had my grubby little paws on...

Suntour had Ultra 6 speed- those won't index with an Accushift/SIS setup; but a regular spaced Suntour 6 speed will. From what I'm aware, spacing is the same across 5 speed and 6 speed between Accushift and SIS; although you'll need to pair SIS shifters with SIS derailleur- the same with Accushift. However you can use a Shimano 6 speed freewheel with either combination. I'm also using an IRD 5 speed freewheel with Accushift shifter/derailleur set.

I haven't had any experience with Accushift 7 speed. It's my understanding that Accushift 7 speed has uneven spacing- like 5 speeds are normal and then two are closer together- or something to that effect. So an SIS shifter/derailleur combo won't work with that as they're designed to pull the same set distance per click.

Suntour Alpha Accushift is a system of its own- it doesn't match regular Accushift nor SIS. I think those were the @3050 and @4050.

The goofiest thing I had going was an old (pre-indexing days) Suntour perfect freewheel mated with a Suntour XC Comp derailleur and Dura Ace 7400 shifters. I was running it in friction- and thought I'd try indexing, pretty much as a joke- and it worked gloriously.

I have several bikes using Shimano 6 speed freewheels and Accushift shifters and derailleurs- it works as perfectly as an all SIS 6 speed setup.

OldsCOOL

I have a mix of these parts as many of us do. This winter I'm building a spare bike with an accushift 6sp shifter, 6sp Suntour 13-34 FW and Shimano deerhead M700 RD. If it doesnt index, no biggy. If it does? I'm grinning on that first ride.

crank_addict

The BEAST by Suntour / Browning. Electronic index shifting, circa 1990.

bikemig 

You're taking this puppy up to the dairyland dare, right? I'm bringing my bungie cord if you do,

trentschler

This Accushift bulletin at Yellow Jersey has a pretty complete description of indexed shifting - Suntour Technical Bulletin #21 "Accushift Problem Solving" in 31 Pages

Basically, you can't use indexed shifting with Ultra-6 freewheels. But you can with regular spaced 5-, 6-speed, and with Ultra-7 freewheels. You need the appropriate shift levers and rear derailleur. These are described in the bulletin. I have Sprint 9000 shifters and rear der on one bike shifting a 5-speed Winner Pro freewheel, and Superbe Pro shifters and rear der on another with a 6-speed Dura Ace freewheel. That works OK, too. The shift levers have options for friction shifting, regular spaced fw, and Ultra-7. I haven't tried the U-7 yet. I've also found that the Winner Pro bulletin reprint from Yellow Jersey is really helpful, too - Suntour Freewheels at Yellow Jersey

ramzilla

I've got several sets of NOS Suntour thumb shifters. I can't remember off the top of my head but, I think they're model number 3000 - 5000 Accushift or something. They're well made sturdy attractive items. Been using them on my upright handle bar conversion bikes. The lovely thing about these little thumb shifters is the built in feature that allows switching from index to friction. Sorry but, I've been setting them all on friction of course. I'll have to experiment with the index feature & get back to you about the results.

RobbieTunes

What about GPX 7-sp; Is it evenly spaced or narrower on the last two?

top506

Robbie, the GPX on my '89 Ironman works better with a Shimano spec freewheel than it does with the SunTour that came on the bike. Just as loud, though.

Top

masi61

I have 2 bikes indexed Accshift. A 7 speed X-1 rear derailleur, with a winner pro 7 speed freewheel & Superbe Pro 6/7 speed Accushift down tube levers. Shifts perfectly! Crisp, solid shifts across the full range.
The other one is an 8 speed. It is an even cooler setup than the 7 speed. Suntour Superbe Pro cassette hub with a custom 12-26 8 speed cassette. The rear derailleur is an accushift compatible XC Pro short cage shifted with "command" 7/8 speed accushift shift levers in a slick set up on my Cinelli Nerve handlebars on my Cannondale CAAD3 R1000. Super durable, crisp shifting set up that rocks!

Ronsonic 

The only problem is it was designed by the wrong Browning. If it'd been John Moses Browning we'd be riding nothing else and it would work all the time.

top506

And would have a multitude of small, hard to machine multipurpose parts. And if one of the Winchester guns, non-standard screw and thead sizes.
No worse than working on a '60s Raleigh, I suppose.

Top

Velocivixen

My 1990 Trek 930 was all Suntour 7 speed mountain components - X-1 I believe. Even with new cables/housing, and after reading this forum for fine tune tips to get it just so, I wasn't impressed. I had the below the bar X-1 thumb shifters, correct derailleurs and freewheel. I even have Suntour 7 speed bar end indexed shifters. It just didn't work consistently well.

dddd

A few added notes:

Ultra-6 freewheels are spaced like Accu-7 freewheels, with the largest three cogs closer together.

The larger cogs of an Accushift freewheel usually have "index" and a directional arrow stamped onto their back side.

740X derailers had about the same actuation ratio as their earlier road and touring derailers, and about the same as Suntour Accushift derailers.

In fact, it seems like most traditional derailers had about that same actuation ratio, even the Gran Turismo which I tested.

The Allvit is an exception in that it has a regressive actuation ratio approaching the largest cogs. It works more linearly with four cogs however.

Narrower, modern chain helps reduce any noticeable effects of indexing mis-match. I used a 9s chain to get a 7s Athena Synchro system to work quite well with a Sunrace 7s freewheel.

Non-Dura-Ace Shimano rear derailers need slightly greater cable pull to move the same amount. This began with the first 600 SIS derailer and continues to this day, with the exception of their latest (11sp) derailers.

Accushift shifters have a large amount of overshift freeplay built in between the lever and indexing plate, so as to make the chain actually engage a next-larger cog instead of just rattling against it. Shimano's HG chain and cogs didn't need that much overshift movement. Narrower modern chain negates some of the problems of excessive overshift, preventing the chain from contacting the next-larger cog than the one you are shifting to. This Accushift characteristic became problematic with the narrower 7s system, especially when used with ramped cogs. 9s chain fixes this problem, so cable adjustment becomes less critical and service intervals longer between adjustments.

RobbieTunes

Thanks, Top. That's the closest thing I've ever gotten to an answer to that question. People tell me about this freewheel, or that freewheel, but what I've never been able to find out is what GPX actually is, and what the spacing is, what works, and what is supposed to work. None of my GPX stuff says Accushift or Winner or Campbell Soup, so the references to those don't help a lot. Thanks.

bikemig 

I had suntour xc pro 7s on my team specialized stumpjumper; it never worked all that well. I ride it in friction now.

The Golden Boy 

GPX should be just a group name. Like Superbe Pro, Sprint, Ole, Edge or Blaze

Velocivixen

There is one of the particular groups that has something special about it - maybe the 4050 or ? In that group the rear derailleur had to have its specific shifter for it to work in indexing. I'm fairly sure it wasn't the 9000.

dddd

That would be the 3040 low-end series, there were both road and mtb versions of this.

The 3040 series cog spacing was normal Suntour Accushift. The shifter and derailer were unique in that the cable pull was different, I believe it was longer, more like Shimano (or the even-longer pull of Campagnolo's Ergo derailers with their even further-reduced actuation ratio of cage travel to cable travel).
The 3040 series parts may have been limited to only a standard-spaced six speeds by the way, further increasing service intervals of poorly-maintained entry level bikes.

All of the better gruppos, from Edge up to Superbe Pro used compatible indexed shifters and derailers, which moved about as much cable as the 740X Dura-Ace pieces.

The 7s freewheel cog spacing of all of these gruppos was the same asymmetric spacing with narrower spacing between the three largest cogs.

Seemingly little known is that Shimano SIS-7 and Hyper-7 cog spacing is also always asymmetric. The black spacer between the 2nd and 3rd-smallest cogs is 3.3mm and the other (grey) spacers are all 3.1mm. This means that a rapid-rise (low-normal) derailer will never index quite right with a 7s cassette.
Suntour's narrowest 7s spacers were only 2.8mm iir, but their cogs were perhaps a little bit thicker as well.

Velocivixen

@DDD - Thank you for this very helpful & detailed information. Really good to know for future builds or those trying to figure out Suntour indexing.

kevlar_heart 

Greetings: I hope to stir the pot here as I am refurbing a 1989 Specialized Allez. It was my back up to a Specialized Allez Epic I used to race (poorly) The Allez came with Suntour GPX components with the 7 cog cassette. Currently the Indexed shifting works like a champ. I am planning on replacing cables and chain so I am anticipating for real fun getting the bike back in order. I haven't found a reliable reference guide for setting up the components...The Suntour guide referenced in this thread is the generation just prior to the GPX line...any resource appreciated.
Allez specs.jpg

1989Pre 

The Suntour Alpha 6-speed freewheel is the only Suntour freewheel I know of that is designed for indexing (Accushift). It was a new generation of freewheels, that came after the Winner, New Winner and Winner Pro. The three highest cogs on the Alpha are beveled, where-as the earlier Suntours were not.
I could never get the Accushift to stay in proper adjustment, whether using the @3040 or GPX, so eventually, went to friction.

OldsCOOL

I'm reverting the '89 PRE from fixie world. Finicky indexing? Sheesh, I forgot how finicky the 3040 is to set up and work properly. I have never had problems like this with Shimano.

A big thank you for posting the tech link from Yellow Jersey! It seems Suntour set these up to require their special chain and freewheel. If one is patient these can be set up to work but it will never be the smooth and silent shifting of the 105 or 600.

While riding, if you can envision a little monkey sitting atop your water bottle and playing with your shifter you will find it tolerable.