dddd

Vintage derailers, even the vaunted Suntour derailers, do not handle large chain gaps well at all when using today's flexible chain designs.
What worked well with older chains up through the Sedisport era cannot be expected to work well with chains that are today twice as flexible laterally, even as the newer chains feature bulged sideplates.

What will help matters most is a derailer like a Shimano Deore or Huret Duopar, which can maintain a tight-enough chain gap while traversing wide-range freewheels.

I've found that many Suntour GT-cage derailers work best on even larger freewheels with their B-tension screw removed entirely, when using any modern chain.
And on other brands of vintage derailers, finding a way to adjust the derailer body angle without having a B-tension screw to play with (by tweaking spring tensions, or by modifying the stop lug on the derailer or claw hanger) was time very well spent!

Once the chain gap is tightened up, I further recommend adding some kind of polymer anti-friction noodle to any/all contact points between the cable and any metal guide surfaces, to give much better, more-accurate derailer movement in response to shift lever movement (this after oiling up the shifter's central pivot and friction surfaces).

so-ichiro, what derailer are you using?

so-ichiro

I can relate to this. I will post a video of my shifting experience below.

Wow, that's awesome! I appreciate sharing your experience on this. I was getting a little frustrated with the shifting issue, and the second guessing this bike purchase.

so-ichiro

Thanks for your suggestions. Yes, I have a rear derailleur alignment tool from Parktool, and checked the alignment before installing the rear derailleur. I was hesitant to purchase the alignment tool due to its cost, but, about 8 years ago, I bent the hanger of my bike, so I bought it then, and always use it to check the hanger of my vintage bike purchases.

That must be very satisfying to solve the issue like that. My Suntour freewheel does tend to pick up the chain at the middle cogs, but no problem with the outer cogs of the freewheel.

so-ichiro

The derailleur is a Suntour XCM 3040 and the shifter is a Suntour bar-end shifter. Both are original to the bike. I did not see the b-screw on this derailleur

Here's a video of the freewheels in action:

canklecat

Ditto, dddd's advice.

Bar-end shifters can introduce a bit more friction and slop. I use Shimano 8-speed bar-end shifters on my favorite hybrid, an early '90s Univega, with a Shimano Exage 500CX (nearly identical to the Deore LX).

That bike originally came with cable liners, basically flexible straws just large enough to accommodate bare cables, but much smaller in diameter than conventional cable housing. As the original cable liners aged and cracked the shifting friction increased where the bare cable rubbed against metal guides.

For awhile I couldn't find any cable liners so I tried hollow plastic stems from cotton swabs. Turns out those work just as well. I use 'em on all my bikes wherever bare shifter or brake cable rubs against metal guides -- under the bottom bracket, the brazed on metal guides on the top tube and seat cluster where the top tube, seat tube and seat stays intersect, etc. Really helps reduce friction for shifting and braking, probably helps make the cables last longer too. I don't bother with any grease. Once in awhile I need to nudge the makeshift liners back into place -- over time with many shifts and braking cycles they creep a bit one way or another.

BTW, the KMC Z50 is closer to older style chains. The side plates still have a bit of chamfer on the inside edges, but not as fancy as their other chains. Might work a bit better with the original Suntour freewheels.

drisee

I have a quick freewheel question so i though i would drop it here. Working on a vintage MTB build and need to complete the drivetrain with a new freewheel.

I'm upgrading the front thumbshifter and the rear derailleur to the Shimano Deore MT60 series. Single chainring on the front, no FD. Looking for a Shimano index compatible 6-speed freewheel and would love a recommendation. Gearing is not that important as the build is more of a cool grocery getter.

How do i know which vintage 6-speed freewheels are index compatible?

Thanks for your time.

BFisher

Shimano still makes a 6 speed freewheel. Here's one - Shimano 6 Speed Freewheel Sunrace would also work with indexing.
Used freewheels can be a crapshoot.

icemilkcoffee 

I would buy a new Shimano 6speed freewheel instead of some used vintage ones. It's hard to judge wear on freewheel cogs.
According to Shimano's docs anything with small cog >=13T and large cog <=32t should be fine:
https://si.shimano.com/api/publish/s...000-00-ENG.pdf

drisee

Thank you for the replys. @Icemildcoffee that's a great pdf to reference. Love that level of technical detail. I'm trying to keep the parts vintage so i'll be looking for a compatible used one. Crazy to see how much the NOS ones are going for. I'm just looking for a good used one.

Thanks again. Happy riding.

pastorbobnlnh 

A Sachs 6-speed freewheel should also index with Shimano index shifting.

El Chaba

Others have written the same but I will add my observations and experiences to the good…..There is NO a comparison between the free wheels made today and the good ones from when they were a current product. It is well worth looking for something older and of quality. My favorites for high quality were the Maillard 700 and it’s successor branded as Sachs and the Regina CX /CXS which became the America model. On the Maillard 700, you can even flip most of the cogs likely to wear and get a whole second life from them. Once you have a quality freewheel(s) change the chain very early in the wear cycle as it is replaceable, but doing so will greatly extend the life of the freewheel cogs. Treat them as an irreplaceable asset, because they nearly are. I love freewheels for some strange reason. A couple of years ago, I was lucky enough to come across the pictured Maillard 700 6 speed kit that allowed you to assemble a freewheel in a number of configurations. Fun stuff.

pastorbobnlnh 

Great advice El Chaba ! Let me also add my two cents to your great advice:

Remove the sprockets from the freewheel body and clean them, at least yearly, and more frequently when riding in dirty conditions. The combination of a clean and well lubed chain, clean sprockets, as well as clean chainrings, and RD jockey wheels and pulleys, increase the life of all the drivetrain bits exponentially.

SurferRosa

The problem I've had shopping for new Shimano freewheels is the writing on the big cog, which is so brutally ugly when mounted on a nice vintage road bike. A few years ago, I did find a bronze colored Shimano 5-speed on ebay in Taiwan free of any ugly label. It was a little more expensive. Still got it and still holding up.

droppedandlost 

what marketing genius came up this idea. has the exact opposite effect. I refuse to purchase one.

BFisher

@SurferRosa, I agree. I think there is still a segment of the market that sees SHIMANO and automatically equates it with better.

I haven't done this, but I wouldn't hesitate to take that large cog to my wire wheel and knock the branding off. At least Sunrace offers shiny ones.

El Chaba

A couple more thoughts/observations on the subject…..In looking for vintage freewheels, it is always helpful to know if they have standard or narrow spacing if a 6 speed…( narrow being a 6 speed freewheel designed to fit in the space of a 5 speed, I.e. a 120 mm rear hub). You may come across a Shimano Dura Ace freewheel. These were probably the models with the highest level of precision machining of any freewheel body ever made. You may also come across a SunTour Winner. These freewheels also featured very precise bodies. There was a less expensive SunTour Perfect model which was not bad at all. In general, the Japanese freewheels seemed to have softer cogs and didn’t wear quite as well as say Regina or Maillard (Sachs). I would look at these carefully for cog wear as this far down the road wear is VERY likely to be a factor.

drisee

Just a quick update on how i resolved my freewheel search. I wanted to keep it vintage in both look and spirit, so we went with a vintage Shimano 6-speed MF-Z012. It's one of the freewheels as called out on the tech doc shared earlier that is compatible with the thumbshifter. So we should be good to go.

And btw i couldn't agree more with the look of the new shimano freewheels with the writing on the granny gear. Horrid. Thx everyone.

gugie 

I don't build or rebuild rear hubs that take a freewheel anymore. I have 1 bike that has a freewheel now that will probably outlive me.

Somebody had to say it.