steelbikeguy

my two videos provide a good comparison of the "bushed vs. bushingless" comparison.
The bushed is stiffer, so the chain will follow the pulley better.
However, the bushed chain has no features to help the chain get up onto the adjacent cog like the bushingless chain has (typically).
The net effect is that the bushingless chain ends up shifting better, in my experience.

One common attribute of a bushed chain is that the rivets/pins protrude beyond the side plates...



Steve in Peoria

daka

Those protruding rivets look like they'd be great noisemakers! +1 on modern bushingless chains shifting better, even with old derailleurs and freewheels. It also helps if your plastic idler wheels aren't worn out. Changing out a worn out, thin pair of idlers on a Campy NR to some NOS Suntour idlers made a noticeable improvement in shifting. I don't think it was the change of brand that was important, just having more material on the "teeth" made the chain follow the lateral movement of the derailleur better.

reroll

Actually, having to over shift and then trim back is normal. These derailleurs are from the 5- and 6-speed era, before Hyperglide sprockets got developed.

cudak888 

It appears as if both freewheels are Shimano Uniglide, and while I can't tell offhand whether either of the chains are bushed or not, the "not smooth shifting" chain has much larger side plates and pins than the former, common of bushed chains predating ramped freewheel cogs from the 1970's.

Have you considered swapping the chains just as a test? I'd wager the "smooth shifting" chain on the Suntour RD and Shimano Uniglide freewheel ought to perform better than the existing chain on it now. A new 6-speed chain off Amazon ought to duplicate that performance as well.

-Kurt

Road Fan

I would think about the physics of derailleur shifting, courtesy of Frank Berto - how do chains transfer from cog to cog just by lifting a little lever? The problem is happening on several derailleurs on all or nearly all upshifts, something central is going on - it's not just a few blunted teeth with rounded edges or bent corners. A chain on plain sprockets needs to be overshifted to move into the path of the larger sprocket and become lifted off its previous running gear. It would have trouble getting it done if the chain is too narrow, is too stiff in lateral bending, has worn sides (somehow?) encounters worn teeth, or is not pulled back hard enough (weak pivot spring or draggy old grease in the spring pivot). The feature of the chain which is grabbed could be a side plate or the little end of the pivot pin. If it needs more overlap one can only pull the lever more, which may cause engagement or more of the churning and grinding which is among the causes for complaint in the first place. If the chain is too narrow it needs more overshift to hook a tooth and be pulled up.

As well, the spacing between cogs could be at fault. For example some 6-speed freewheels have narrower pitches. The old SunTour Ultra-6 were made to fit in the same width as a conventional five speed cog from the early 10-speed (2 x 5, ya know, not 2 x 10!) days. They could grab the chain more readily because the chain doesn't have to move over as far to be grabbed. A very narrow chain such as a 9 or 10 speed could also need additional side force to engage the next cog.

Plus, if the chain is not pulling hard enough "against the shift" it would not grab the next cog and be lifted. It might be that the lower pivot "P-pivot?" spring could be tightened with an acjustment, cleaning inside the pivot, or even a new spring.

It's not an easy problem, but it has helped me to know more about what's really going on.

Road Fan

If the chain is moving around sideways on the idler wheels, maybe the chain is too wide?

reroll

I have bikes with 5- and 6-speed freewheels and 7- and 8-speed cassettes and a few months ago I searched to see what sorts of chains would currently be available. I did not find any of the older style 5-speed chains, nor any 6- or 7-speed specific chains, but KMC makes 8-speed chains which are made to approximately 7-speed specifications, although not much difference between those two, and there were a number of reviews saying they are being used on 7- and 8-speed gear trains and also successfully on 6-speed gear trains but there was no mention of its use on 5-speed gear trains. 5- and 6-speed chains have the same internal spacing, 7- and 8-speed are narrower, but 5-speed goes back to square-cut sprocket teeth, before their having tooth modifications, twisted teeth, Uniglide and Hyperglide and those nubs sticking out from the ends of their link pins were actually useful. Early 6-speed had square-cut sprocket teeth too but then began serious experimentation resulting in the ends of 6-speed link pins being flush with the outer link plates, no more nubs. I have a 126mm bike set up with a modern 6-speed HyperGlide 14-34T Megarange freewheel running on KMC 8-speed chain on 9-speed F&R derailleurs, works fine.

cudak888 

Shimano's (and SRAM's) 7 and 8-speed chains should be identical within their respective offerings, barring any specialty versions for any one particular lineup. Same for aftermarket; a Shimano, SRAM, KMC, or Amazon knockoff 7-speed chain will fit 8-speed without issue and vise-versa. There shouldn't be any "approximation" between them, other than differences between manufacturers themselves may engineer into their own versions of the chains (SRAM's 7/8 being a bit narrower than the rest, for instance) - but even still, I've yet to see any specific variant lose compatibility in either direction.

It's also popular today to put 7-speed chains on 6-speeds these days because of availability - and because it generally works without issue, but six speed chains BITD were wider, and ran the gamut of link shapes, sizes, and widths. I personally don't care for it as it either obligates me into Shimano's chain pin or a quick-release link, while you can still get away with reinstalling the pin on a 6-speed.

I wouldn't be too worried about putting a current-era 6-speed chain on a 5-speed Shimano Uniglide (twist-tooth) freewheel though, provided it's a modern 6-speed chain designed to accommodate 6-speed Shimano indexing. The OP appears to have a Uniglide on both bikes (clearly so on the rough-shifting one, if not the other), and I'd expect it to perform better with such a chain.

In fact, I'd go further to suggest that UG freewheels are the one case where, today, I wouldn't recommend using a chain originally designed for friction shifting. I'd always grab a KMC or Shimano-compatible 6-speed index-capable chain for it. Wide enough to span the 5-speed spacing, profiled enough to ride fairly quietly on the twist-tooth UG profile.

-Kurt

reroll

In my searches for bicycle component specifications I often find little from manufacturer's or producer's records and far more from independent researchers who made their own investigations yet that raises questions about whether the specimens they examined were representative of all of what was produced and about the accuracy of their measurements, so I usually go with the "taken with a grain of salt" method and regard such information with just a bit of suspicion.

I have seen 8-speed chain specifications the same as 7-speed chain but have seen others which are internally very slightly narrower but taken with a grain of salt I interpret that as meaning they are practically the same with not enough difference to be concerned about. In my recent chain search I half expected to not find any 5-speed chains, had a bit more expectation to find 6-speed chains and the last time I looked KMC was making 7-speed chains, but no more, their smallest now being 8-speed chains and the chain reviews I read were saying their 8-speed chain allegedly made to 7-speed specifications is the way to go for 6/7/8-speed but nothing was said about 5-speed.

I have two early 80s bikes which were 2x5-speed yet with 126mm dropouts and although they are in fine condition they are not collectors items and so I did not hesitate to upgrade them to 3x6-speed. My only question is about how much longer 27 x 1 1/4 inch tyres would be available, maybe a legacy size which would be around for a good while longer.

Good yakkin' - Doug

cudak888 

I'm not relying on manufacturer specifications either - it's a combination of what I've learned from Sheldon, BF, the rest of the Internet, and about 15+ years of experience fooling about with more chains and freewheels than I care to think of.

Every manufacturer will have a different way to ramp their chains, and because of Shimano's various patents, cassette cog ramps tends to be different as well (a couple of infringement cases come up immediately on Google). Yet, in my experience, the vast majority of online scuttlebutt is correct: Between standard seven and eight speed systems, nothing much matters between manufacturers when it comes to 7-speed chain and cog compatibility (excluding Sachs, who was still running Sedis 6-speed style chains on their 7-speed, non-ramped freewheels). Plus, last time I bought a KMC 7-speed chain, it was marked 7/8 compatible. Same for the knockoff Amazon sold me recently under the fly-by-night batch-brand "Camper Matters." Don't recall what the chain was, didn't matter - it worked just as it should.

Come to think of it, I can't remember ever buying any 7-speed chain that wasn't marked for 8-speed and vise-versa. The only exception to this would have been a Shimano IG-70 chain I bought which was marked specifically for 8-speed. It was basically an HG chain with additional quarter-round catch ramps stamped into the outer plate edges. It probably would have worked on a 7-speed system as well, but I dare say Shimano's marketing preferred emphasizing their holistic IG chainring system rather than letting in that the same chain could be used outside of that system on their 7-speed systems with no real difference at all. (The horror!)

While I cannot confirm this, I'll wager with near certainty that the only reason 6-speed chain isn't sold as 5-speed compatible, today, is because of the various older 5-speed freewheels out there with notches in the top of the cog teeth, e.g., Atoms and Reginas. A modern 6-speed chain can ride straight up onto the notches and never engage with the cogs, causing immediate loss of resistance at the pedals. Atoms in particular are notorious for this, even sometimes with their stock chains. There's a lot of potential for various painful spills here. Now, that same chain will probably be just fine and dandy on a Suntour 5-speed and most certainly on a twist-tooth Shimano Uniglide 5-speed, but what's the incentive for brands to do that? I'm sure most of these brands would rather just market 6-speed chains as 6-speed and avoid having to do the R&D to determine chain compatibility for a bunch of obscure, defunct equipment. Plus, they risk a liability lawsuit if someone ignores the fine print and mates a 6-speed chain on an old Schwinn equipped with one of those aforementioned Atom 5-speeds.

Plus, they know anyone determined enough can dig up this forum or Sheldon and find out that a 6-speed chain will work on some 5-speeds. Why risk it when us C&V'ers are motivated to do the legwork after the sale?

But back to the OP's issue: It'd definitely through a modern 6-speed chain on that old UG 5-speed. Should do much better than what's on it now, which looks like some Perry or Perry-esque 5-speed chain that's original to the bike, but not original to that freewheel, and certainly going to chatter a bit more. As others have said, the [woefully overrated] Suntour VG-whatever RD doesn't help - it does not have a sprung B-pivot to allow the whole RD to silently move backwards slightly as the chain ramps over the cog teeth during a shift. Be that as it may though, the chain isn't making it any better.

I don't expect ISO 630 to disappear anytime soon. Too much of it still kicking around from the first US Bike Boom. Even if major manufacturers were to ditch it, we'd probably see them eventually pop up in the boutique parts market eventually (read = Jan Heine will sell us beautiful and overpriced 27" skinwalls for $120 bucks each).

-Kurt