Pratt

The 7-speed (13-30t) Suntour freewheel is showing wear and I wish to replace it in kind. Does anyone have advice on a good source? Or should I just roll the dice on eBay?
I'd even be happy with a 6-speed (?-30t) since the small cog, like my big ring, is just for decoration these days, if the indexing would still work.
Thanks in advance.

sovende

If you want an original SunTour freewheel, it’s likely that whatever you find will be “used”. There may be a handful of NIB (new in box) and/or “shop worn” freewheels out there but they will be spendy 🤑. A quick google search revealed a few used ones on EBay starting at $50 ? s&H ?
NIB knock offs can be had for a lot less !!

Bill Kapaun

If you can live with 14-28, that's a common Shimano size.
Don't know the capacity of your RDER, so I won't recommend larger such as 14-34.

dedhed

What Suntour indexing derailleur and shifters is it?

squirtdad

more expensive but IRD makes 7 speed https://www.treefortbikes.com/IRD-Cy...MaAuv7EALw_wcB

Andrew R Stewart 

SunTour used a varying cog C-C dimension on it's freewheels so subbing a Shimano (or one of the knock offs) freewheel might prove frustrating when index shifting. Of course if you can switch the shift lever to friction all kinds of options open up. Generally the amount of rear der cage sideways movement per indexed shift is different for each cog count of the freewheel. So a 6 speed cog will have wider apart cogs then a 7 speed will. So no indexing compatibility is to be expected.

If your shift lever has no friction option then I would ask how much do you like this bike. Enough to replace the cog set (and rear hub/wheel if a cassette), rear der and shift lever? Andy

bikemig 

If you want a suntour freewheel that indexes with your shifters, your best bet may be to put up a WTB in the C&V for sale forum. If you're good on friction, you can buy a new freewheel.

dedhed

Some good information on Suntour indexing here.

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

Pratt

Wow!
Lots of great information.
The rear derailleur says XC Comp.
The bar end shift lever says Accushift Plus 7.
Yeah, I like the bike. It is a Bruce Gordon Rock and Road that I bought in 1992.
If the shifter can be easily converted to friction, that would be fine and I could be happy with any manufacturer's 7 speedier even a 6. The small cog is just decoration for me anyway.
Thanks again, all.

70sSanO

I agree to up a WTB on the C&V subforum. Also, go on eBay and see what is available. I would also see what Suntour downtube shift levers are available.

For the bike you have, spending a couple hundred, or so, to keep the drivetrain in top condition is little, compared with the cost of a comparable bike.

The other option would be to convert to Shimano SIS. Depending on the components, it may or may not be more costly. You would need shift levers, SIS RD, and a Shimano compatible freewheel; a new chain regardless of the direction you go. I would look for older components vs cheap new Tourney level.

John

wesmamyke

I might have a spare 7spd Suntour alpha index FW. Had a couple, one 6spd and one 7spd. Pretty sure I only used the 6spd one. My brain wants to say there is two variations of 7spd accushift though.

Lazyass

I only buy freewheels with ramped teeth now. Most vintage freewheels are not ramped. Shifting is 100x better, especially if you have friction shifters. The Sunrace is great one, I've bought a couple of them. They look good and I've never had a single issue. Shimano also makes one but I think it's ugly as hell.

https://www.ebay.com/itm/25514895844...BoCfPAQAvD_BwE

canklecat

Check around for a SunRace 7-speed freewheel. Those work fine with my 1989 Suntour GPX Accushift group in index mode.

Specifically, try to find the SunRace MFR30 (13-25) or MFM30 (13-28). Both are 7-speed, chromed, with well shaped cogs and teeth to be compatible with Suntour and Shimano SIS 7-speed groups from the late 1980s-early to mid 1990s. I've used the same wheels and freewheels on my bikes with Suntour GPX and Shimano 600 Tricolor/Ultegra setups, and even with later model Ultegra 8-speed bar-end shifters.

I'm not sure whether SunRace internals are built to the same standards as Suntour and Shimano, but they've nailed the cog placement and tooth shapes to be compatible with both. I've ridden a couple of SunRace freewheels (MFR30 and MFM30) since 2017, no problems, no signs of significant wear. I've heard they're difficult or unusual to disassemble for servicing but so far mine are nowhere needing any service.

I also have some Suntour Alpha 7-speed freewheels -- 13-24 and 13-26, IIRC. They don't shift nearly as well as the SunRace in index mode, although they're fine for friction shifting setups. The SunRace shift as well as Shimano, maybe a bit better. When comparing the tooth designs it's easy to see why. SunRace borrowed/stole/plagiarized the best of both Shimano SIS and Suntour Accushift designs, apparently reading the old literature and mechanics guides to learn the quirks and strengths of both systems.

CliffordK

Clean your existing freewheel and post a photo of it.

If you are using E-Bay for used items (not NOS), learn how to look at sprocket wear.

A few wear signs that I commonly see are:

• Elongated valleys between teeth.
• Slanted side on the pulling side of teeth.
• Mashed faces of the teeth.
• Rounded, or even broken tops of the teeth

veganbikes

IRD makes excellent freewheels. Go with one of those they are modern, high quality and minus pandemic issues generally available. Don't go with cheap stuff get quality and IRD is quality.

Pratt

Well, I've learned a lot already, and I haven't even replaced the FW yet. Thanks to all for the various inputs Following Squirtdad and Vegan's advice, I ordered a FW from IRD. It is 32 instead of 30, but my hope is that I can adjust the "B" screw and lower the derailleur just enough to clear the cog.
The yellowjersey site was indeed informative. I learned that there are two types of idler wheels, and I had them reversed.
Stay tuned for further adventures in old bike land.

CliffordK

Pointy one at the bottom,and flatish one at the top?

Pratt

Tapered for the tensioner, squad cut for the guide.

momoman

Have you heard of Pastor Bob and his Freewheel Spa? He specializes in rebuilding and modifying freewheels.

Freewheel Spa

Pratt

Update:
Ordered and received the IRD freewheel, then ordered and received the Park tool to remove it. I was reluctant to put it on if I couldn't be confident about getting it off, especially since it has a 32 tooth, instead of 30 tooth large cog and I was concerned it might not fit.
In the end, it does fit just fine. One little oddity is that the spacing between the smallest cog and the next smallest is larger than the spacings between all the other adjacent cogs. It seems to shift fine on the bike stand, tomorrow I'll take it for a little test ride.
Again, thanks to all who participated in this thread, you were very educational.

70sSanO

Hopefully it will shift fine. You can use automotive feeler gauges to compare the spacing to your Suntour. I have read that Shimano “cassettes” were spaced wider between the 1st and 2nd cogs.

I’ve never had an IRD freewheel, but it appears from pictures I’ve seen that the first cog is threaded onto the freewheel body like the older freewheels. If it is, and you cannot get it to shift smoothly between 1st and 2nd cogs because the spacing is too wide, you could theoretically sand the cog/spacer to get it closer. I don’t find this type of customizing stressful but others do.

John

Pratt

What I would call the first cog is the 32 tooth one. The wide space is next to the 13 tooth cog.

70sSanO

As I have understood the cog position over the years, the first cog, or first position cog, is always the one closest to the dropout and is the smallest cog. Every freewheel/cassette has a first position cog in the same place.

So I am talking about the threaded 13t (1st) and splined 15t (2nd).

John

Pratt

On a little test ride the IRD freewheel seemed to perform fine. Clearance was not a problem. I had been concerned that the 32 tooth cog would not clear the derailleur, and that the "B" screw might not be long enough to make it work. In the end, clearance was fine in all gear combinations even the unlikely extreme cross chain ones. As expected, the derailleur would not shift to the smallest cog (13 tooth, nearest the dropout). I'll have to examine it to see if it unscrews and there is some way of moving it closer to the other cogs. But, it really is just along for the ride, I don't really foresee pushing a 95" gear. Sometimes it seemed a little slow shifting into higher gears, but that may just mean it needs a little adjustment of the barrel to lengthen the cable.
I'll have to count the teeth to see if all of the cogs are larger, but it felt like I could push higher gears than I was accustomed to, but maybe that was just the Hawthorne effect.

70sSanO

My only question is if you set the derailleur up from the 13t. On a top normal rear derailleur indexing starts from the point where the cage is lined up with the small cog and is resting against the high limit screw.

You may have already tried this and it would not shift from the 13t to the 15t and so you set it up from the 2nd position 15t. But if not, even if you don’t use the 13t, it is good to verify this before you start removing material from a spacer you might not be able to easily replace.

John