Classtime 

I'm starting to put some serious miles on my Suntour Sprint equipped Circuit and would like my rear shifting to require less micro-adjusting at the lever. Some of the issue may be my determination to continue using the original cables and housing but I wonder if using a Suntour FW instead of Shimano or SACHS would make a difference. At this point, I am not about to $pend big bucks for a Suntour chain but maybe there is a current production chain that plays more nicely with a Suntour RD than my HG-71?

My PX-10 with its 5s Simplex system and my Medici with its 6s SR don't require so much guess and check with each shift as my Circuit. And with so much love out there for Suntour friction, I must be doing something wrong.

Jeff

John E

I doubt changing the freewheel would have much impact. You may want to try a better derailleur, such as a Cyclone, which is what I run on my UO-8, with SunTour friction barcons and a SunTour 13-26 6-speed narrow spaced ("ultra") freewheel.

crank_addict

Sachs - Aries or Sachs Maillard with the profiled tipped teeth. Not the bent type. Choose an 8 speed chain with inner camfering. KMC budget jobbie are good as anything.

May you pedal hard and sport the yellow. %=)

canklecat

The freewheel matters less than the shifter and chain. That's been my experience with various attempts at friction shifting on my Centurion Ironman and Univega Via Carisma.

A friction shifter with micro-clicks or other trick to retain position against ghost shifting will save a lot of aggravation. Don't bother trying to make a Suntour GPX Accushift system work properly in friction mode. It's fine in indexed mode with the right components, but a huge PITA in friction mode. I never could prevent ghost shifting of the front and rear derailleurs when I'd stand to pedal for sprints and climbs. So it's index or nothing, unless I completely replace the GPX group.

I was able to get the original 7-speed Suntour 13-24 freewheel, and two different SunRace freewheels -- 13-25 chromed and 14-28 blued steel -- working reliably in index mode. The only thing hindering friction mode was the GPX shifters, not the freewheels.

I've switched to all KMC chains on various bikes. Each bike/component group prefers a different chain. With the Ironman GPX Accushift setup it prefers KMC Z51 or Z72 chains. But in friction mode those chains tend to rattle a bit and plain slab-sided chains were quieter. The stuff that makes indexed shifting work smoothly and reliably isn't necessarily the best for friction shifting.

The Univega was less fussy. Both original Shimano index thumb shifters broke so for awhile I used cheap SunRace SLM10 thumbies, with the original 7-speed Univega cassette. After that wheel was damaged when a car hit me, I switched to an 8-speed cassette wheel. It works fine with either the cheap SunRace thumbies or Shimano bar-end shifters in friction mode. I couldn't quite get the index shifting mode happy, possibly due to using a MicroShift brand cassette rebranded as Nashbar. But it works smoothly and quietly in friction mode and I don't need the index shifting. The Shimano bar-ends have micro-clicks to help finesse the shifting and retain position. No ghost shifting under heavy foot stomping pressure.

Regarding trimming the shifter for front derailleurs, I'm not sure there's a way to completely avoid that. Doesn't matter whether it's friction or indexed shifting, front derailleurs will have some chain rub with double and triple chainrings, usually in the extreme or crosschained positions. I've just gotten into the habit of reflexively trimming the shifter in certain gear combos.

The Suntour GPX front derailleur seems to be more picky than some due to the design of the inner facing plate. It's shaped to nudge the chain quickly between chainrings without dropping the chain. This means it will not appear to be aligned with the big ring -- the outer plate of the FD looks slightly askew relative to the big chainring. But when set optimally for shifting, it will rub in some positions. If I tweak it to prevent chain rub in all gear combos, it will drop the chain more often. The latter is potentially dangerous on steep climbs, especially in traffic. So I opt for reliable shifting even though it means I need to trim the lever more often.

bikemig 

I love suntour stuff and that includes their freewheels. That said, you will improve friction shifting by going with a shimano freewheel or a shimano compatible one like the maillard suggested in post no. 3 and a new chain (the KMC 5-6-7 speed chains are cheap and good).

79pmooney

Yes, gong to an older FW with simpler teeth will simplify things. You will have to do more of an over-shift and back to move the chain to the next cog, but those older FWs are far less fussy re: accurately locating the derailleur. (The way all of use were taught to shift half a century ago. Note - some of the older FWs will allow the chain to simply slide over the teeth and not engage with a poorly located shift. Never had this happen to me since I started riding SunTour FWs on the early '70s nor has it happened on any FW I've ridden since. Sedis/Sachs, SunRace or Shinmano.)

The fancy tooth shapes that Shimano was a leader in developing was a huge part of making index shifting feasible, but it is a very mixed blessing for friction shifting. I find modern Shimano FWs can shift the chain back and forth between two cogs if I am careless and leave the derailleur in between them. Very frustrating for a guy who use to race and thought nothing of "dumping" the chain down a bunch of cogs when he hit a hill and didn't sweat exactly which one the chain landed on. In those days (at least with SunTour and now, still, with Campy 9-speed cassettes) I always got a working gear and the chain stayed there. Or it might shift once to the adjacent cog if I really screwed up. You may find you like the SunRace FWs better than SHimano. Rather crudely made but they work. Odd gear choices. And much simpler tooth profiles. More work to shift but it never gets the indecision as to which cog it wants.

Now, new cables and housings will probably make life a lot better. I see them as consumables, especially the cables. Plus many of the new ones are far better than the best of BITD. But they probably will not change this issue with the FW much, just make it a little easier to deal with.
'
Ben

Bianchigirll 

Are you running 7spd? I had pretty good luck using a shimano 7spd HG cassette wheel on Spring 9000 RD and Shifters, but sadly I sold the bike.

clubman 

The Sprint Circuit came with 7 speed Accushift components. Those shift levers should have a ratcheting friction mode in addition to indexing. There's no reason that Sprint derailleur shouldn't friction-shift like butter, especially with an HG freewheel. Maybe the shifters and derailleur should be taken apart for a cleaning. A Suntour AP 7 speed freewheel should also index well, even if it's a little clunky. An 8 speed chain will work fine with your gears.

TiHabanero

The best shifting with Suntour Cyclone derailleurs, Sachs chain, and Barcon shifters happened with the Shimano 600 twist tooth freewheel. Nothing since then has worked so well with that set up. I still use it with a Shimano 6 speed FW, and I have acquired muscle memory over the years to where there is little micro adjusting I do, but still, that old twist tooth freewheel worked amazingly well for a lot of years.

52telecaster

Might want to make sure your hanger is aligned. Generally a sunrace fw and any decent rd will friction shift pretty darn well. I like kmc chains shimano compatible fw old suntour rd and barcons. Works pretty well.

SurferRosa

I just rebuilt an '87 Circuit and used a sunrace 13-25t 7-speed freewheel (new, buy-it-now on ebay for $17) with its Sprint derailleur. "No regerts."

Classtime 

This Circuit must be an early 87 that was equipped with Sprint (7000?) and not the 9000 with Accushift. There is no adjuster on the derailleur and no index option at the shifter.

I just replaced the shifter cable, put on a new housing loop, and spritzed the RD with WD-40 for a short spin down the hill and back. I think it is cleaner shifting. Next step will be rebuilding the derailleur. The HG-71 chain that is on there now is pretty new but it is chamfered on the outer plates only! The KMC chains are chamfered on both outer and inner plates . I will experiment there.

JohnDThompson 

+1 this.

For my money, the best freewheels for any friction-shifting set-up are the old Shimano 600 (MF-62nn) and Dura-Ace (72nn) freewheels with the Uniglide tooth profiles. These are getting scarce lately, and tend to fetch a pretty hefty price. Modern Shimano freewheels with Hyperglide tooth profile are easy to find and much more affordable. They shift just as well as the older freewheels, but don't seem quite as mechanically solid. That said, I haven't had one fail yet.

rickrob 

I use a 7 speed SunRace MF-M3S freewheel with my Suntour VX GT rear derailleur and a KMC X8.99 chain. Shifting works really well with that setup, and it doesn't take much movement of the lever to change gears since it is a 7 speed.

Classtime 

dddd

I would have expected the Shimano HG and the KMC chains to be similar in shifting feel, though sometimes a newer chain gives sharper response to lever movement as the chain is stiffer laterally when new.

I would recommend oiling the shift lever firstly on any old bike that hasn't seen such lubrication in many years.
This can be as simple as backing off the adjuster screw a few turns, tilting the lever and shooting some aerosol oil (actual oil is best) into the gaps that appear on each side of the lever as it is tilted this way and that. Take care that any anti-rotation washers remain indexed on the shifter boss flats before tightening the screw back up.

The gap between the top pulley and the freewheel is adjustable and can effect a huge change in shift responsiveness. Look for a rearward-facing screw head on any Suntour rear derailer which can be screwed outward so as to make the chain gap smaller. In some cases I have removed this screw altogether (even when using a 30 or 32t freewheel) for best shifting performance. See below for how an older Suntour rear derailer might look after removing the screw.
The older derailers were designed for old bushing chain that was very stiff laterally, so chain gaps were typically very large as well, to better accommodate larger freewheels.

nesteel 

Ive found the Superbe Pro setup on my 770 shifts best using a 10speed chain with an Ultra 7speed Suntour freewheel. Just by chance: the night I finished it, the only chain I had on hand was a 10speed. As smooth as it operated, I HIGHLY doubt it could get any better.

CliffordK

I like the new "hyperglide" cassettes, and freewheels. You should be able to find freewheels from 6 to 10 speed.

I have been doing well with 9 speed cassettes, but 9 speed freewheels should be similar, and should be very easy to shift.

I don't think the brand makes a big difference. I like the 11T option with the DNP Epoch freewheels, although they are mostly wide-range, and thus skip quite a few sprockets.

OTS 

This................ absolutely check your derailleur hanger if you are having issues

The Golden Boy 

Sprint sat above Cyclone but below Superbe Pro on the Suntour food chain.

John E

Oops -- my bad. I defer to the other comments regarding setup, jockey wheel float, etc.

The Golden Boy 

I see you've got it pretty much straightened out- so that's good.

I would not fork out for a Suntour chain- chains have just gotten better over the years. Even for 6 speed Accushift stuff, I've been using SRAM PC870/850 and Shimano "6-7-8" speed chains and gotten great results.

Even for running 5 speed friction- I got so much better results using modern housing.

The Golden Boy 

Suntour started coming out with so many different groups- and then inserting things between the long-established "Superbe - Cyclone" hierarchy. It's not difficult to get confused (or more like it's pretty much impossible to get it sorted out). I thought SL was lower end- but it occupied the spot directly under Superbe Pro.