Are you sure you're not looking at the wrong end of the bike to extend the gear range?

Velo Orange Grand Cru 50.4 Crankset

But the 6207 crankset looks so nice, and it's got the original Biopace chainrings!

The story continues....

Last week I ordered a Sachs Maillard LY91 7 speed, 13-30 freewheel off Ebay. I didn't want to mention it till I got it and confirmed that it would fit on the hub. I had a spare wheelset with a 6 speed freewheel, so I laboriously (with the help of a rubber mallet) removed from the hub, and spun on the 7 speed, which went on perfectly. While it was on the wheel, I removed the cogs, which also took considerable effort! I wasn't satisfied with how it spun, so I followed the instructions I'd read here, got out my trusty punch and hammer, and hammered the lockring/cone into submission. Before I spun it completely off, I remembered to take the freewheel off the hub - only dropped one bearing! Once I had it over a tray, I finished taking it off the wheel and put all the parts in the tray, including 71 (yes I counted them) ball bearings. It wasn't full of peanut butter. More like oil full of fine grit.

SO I washed all the parts in water with Dawn, rinsed in hot water and set aside to dry. The bearings I cleaned by rolling them between two sheets of clean paper towels till they stopped leaving greasy tracks. Then I carefully dried all the pieces and set to work. Pawls first, and a big drop of Phil's Tenacious Oil on the hinge end of each. The I put a mess of Phil's Waterproof Grease on the larger bearing race, and using my watchmaking tweezers, put what seemed like a good number of bearings in it. Then I gently slipped the part with the pawls in, rotated it a little and *clunk* it dropped into place.

Flipped it over, covered that race with grease and loaded it up with bearings When I was done, there were too many in the small race, plus two left on the tray. SO I took one out of the race, popped the inner part back out, and put those 3 bearings in the bigger race. Put it all back together, installed the cone/lockring, tightening it down with pin spanners (it hit a hard stop), and put it back on the wheel to try it out. MUCH better!!

Next I cleaned the cogs, which has some surface rust with Dawn, water, and aluminum foil, which helped a lot, but not completely. I reinstalled the cogs (the 3rd one and the first 2 thread on)

Next, I just HAD to try the whole thing on the bike! The freewheel on that took a little less convincing. I threaded the new one on, put in the QR skewers and slipped it into the frame. It fit! Plenty of clearance between the cogs and chain, and the seat stays! BUT the chain is sized for a 26T max cog, and the RD is short cage, so that's my next magical trick.

No pics yet - the bike this is going on needs a good wash first! But it should be ready to go later in the week! The long cage RD is here, I greased the pulley wheels and oiled all the pivots.

Now if I can just find a few 8-speed links.......

Incorrect. Chains are the same from 6-8 speed and most 6-8 speed chains are clearly labeled as such. Google "Shimano HG71", for example.

Incorrect. The chain you are talking about is a modern 8 speed chain that is sold as compatible with 6 and 7 speed as well.

But as is clear from my post, original vintage 6 speed chains were wider than both 7 speed and the even narrower 8 speed chains. 5 and standard 6 speed chains were 7.8mm wide for the 5.5mm cog spacing, while Ultra 6 and 7 were 7.3mm for 5mm cog spacing and Shimano 8 is 7.0mm chains for 4.8mm spacing.

So you think an 8 speed chain is narrower than a 7 speed chain? Oh brother. You really shouldn't be giving out advice in a cycling forum.

FWIW: Bike Gremlin appears to pretty much agree with Kontact .

https://bike.bikegremlin.com/3555/bi...tandards-table

https://bike.bikegremlin.com/1220/1-...mpatibility/#3

Edited to Add: Also FWIW, I believe that's why a few early Shimano products (e.g., chainrings) in the late 1980s/early 1990s were marked "Narrow Chains Only".

Oh brother, I have been working as a mechanic since before 8 speed came out, and you are making a fool of yourself.

Yes, the original 6 and 7 speed chains were wider than Shimano 8 speed, and that was blatantly obvious when looked at them. On top of that, Shimano made you use a special one time pin for their 8 speed chains because side plates had gotten too thin for re-riveting like you did for 5, 6 and 7. (8 speed chains for Sachs, Mavic and Campagnolo were 7 speed width because their cog spacing was the same as 7.)

Since there is no need for dedicated 6 or 7 speed chains, modern manufacturers simply sell 8 speed chains with quick links (no re-riveting) and call them 6, 7, 8 speed chains - even though they work for 5 speed as well.

But Shimano and KMC don't, nor do any of the other trusted sources like Sheldon Brown, nor do the actual specifications of the equipment. 6, 7, and 8-speed chains have the same width and this is widely accepted, common knowledge.

Well, it's all moot because I run SRAM 8 speed chains on all my 6, 7, and 8 speed bikes. I was using8-speed Sachs chains back in the 90s as I recall and there were no quick links. I always re-riveted them.

This is true today, almost certainly for reasons related to economics and manufacturing. It was not true when those chains were initially (1) specified, and (2) produced.

Given the same internal width, a narrower chain will generally work on a system originally designed for a wider one provided it's not narrow enough to jam between cogs or chainrings. (Chains for 6-, 7-, and 8-speeds have always had the same internal width.) Specifically, a 7.1mm or 7.3mm external width chain - the typical external width of today's 6/7/8 speed chains - will generally work acceptably on 6-, 7-, and 8-speed drivetrains, as well as most vintage 5-speed drivetrains.

Because of that fact, manufacturers today simply don't bother to manufacture and market 3 separate chains for this older segment of the cycling market. It's far cheaper to manufacture/distribute/market one product than 3. Separate tooling, packaging, and distribution costs are not insignificant compared to a those for a single product.

I have read (but haven't personally experienced) that some older drivetrains - e.g., some older 5-speed and perhaps some 6-speed - actually need wider chains for proper shifting. That's the only reason I can see why 6 speed chains (like the KMC Z6 and a current 5/6-speed offering from Giant available thru Performance Bikes) are still in production, or why the KMC Z33 was produced up until circa 2020.

Of course. I use Shimano HG71 on all my 6,7, and 8 speed bikes (I have all three) but KMC and SRAM are the same. Same chain for 6,7, and 8 speed. I thought everyone knew that, but apparently not.

Man, you can't take a hint. KMC didn't exist in 1986. But you can find all the old tech docs for Shimano. I very clearly told Gene that he might have a problem if the 40 year old bike has the original chain, not that modern 6 speed replacement chains are wider.

You probably have Google on your computer. Try using it instead of doubling down on your ignorance.
The Sedis 8s were actually 7 speed chains because the Campy and Sachs 8 speed spacing was the same as 7. They probably worked fine on steeper Shimano mtb cassettes, though.

Yep. But cables and chains are the FIRST things I replace on old bikes. That and bar tape.

I took a day off of work, and one of my chores was to fit the new freewheel and derailleur to the Ironman!

It all went smoothly. I had discovered I needed to lengthen the chain just a bit to get from 26T to 30T, and I found exactly the spare piece of chain I needed! For all I know it might have come off this chain, but I've been running SRAM PC-870s on everything < 8 speed, so maybe it's from another one. Doesn't matter. I think it was the perfect length - essentially 2 full links, so 4 extra teeth. SO I took out my handy chain tool and added them.

Since the cable is relatively new, I just pulled the crimp off the end, removed the old RD, checked hanger alignment, and installed the new (to me) long cage RD-6207. The seller had polished it, so it is nice and shiny! Installed the old cable, ran the newly expanded chain and closed it with a quick link, and started checking the limit screws. The high limit screw was way off, but the low was fine. It shifts pretty well! Of course, it's friction, so that's not surprising. I'll have to wait till tomorrow to ride it unfortunately, but still, I'm happy with it.

Some pics - don't mind the dirt, I'll be washing it the next sunny day!

There's a couple mm of space between the chain and the seat stays, so I won't be needing to fiddle with spacers and dishing.



Here it is in the extreme combinations:
First, Biggie Smalls:



Next Biggie Bigs:



Smallie Smalls:



And Smallie Bigs!



Looks okay to me, but I have a whole 'nother chain I can cannibalize.

I spent a little time counting teeth on the new, 7 speed freewheel and comparing it to the old one.

Old 6 speed: 13..15..17..19..22..26
New 7 speed 13..15..17..20..23..26..30

Slight difference in the gaps, but it should be pretty much what I was asking for - the same gears plus an extra lower one.

Inner (roller) width is the same for 6, 7, and 8 speed chains.
KMC, to name one, often makes and sells the same chain outer width for 6, 7, and 8 speed cassettes.
I suppose it is cheaper to run the same width to cover more "sizes."
There used to be a time when I could get 6 speed chains for a lot less than 8 (or even 7) speed chains - and those chains were wider (and often made by KMC, if memory serves me).

For some reason, the pinned chains for higher-speed systems don't follow this trend (they don't make and market an 11 speed chain to cover also 9 and 10 speeds).
Maybe it's because the tolerances are tighter (more tightly spaced cassettes), or because of how manufacturing machines are set up for chains joined with pins that don't protrude past the plates.

Chain standards listed and explained:
https://bike.bikegremlin.com/3555/bi...ion-standards/

A wider (call it "old style") 6 speed chain will get stuck on a more narrowly spaced 8 speed cassette, but a narrower 8 speed chain will work fine on a 6-speed cassette.

With 9+ speeds, inner chain width is also narrower.
Having said that, I rode a 10 speed chain on a 7 speed cassette with no problem (but riding a 7 speed chain on a 10-speed cassette is more likely to be problematic).

Chain compatibility (mix-matching) explained:
https://bike.bikegremlin.com/1220/1-...compatibility/

It is entirely possible that I'm wrong (just like Sheldon could have been - only he can't be asked or corrected any more, unfortunately), but this is as far as I know, as of today.
If I come across convincing enough information to prove otherwise, I'll make sure to update my notes, as always.

Relja

You've provided links to your own website. No surprise that you agree with yourself.

But if I have to pick someone that is wrong, it's not Sheldon Brown. He, along with every other source you care to look at, will tell you that 6, 7, and 8 speed chains are the same, and that's true for Shimano, KMC, and SRAM.

Like the OP, I have a 1985 Ironman (now on loan to my son) but I left it 6 speed. Guess which chain I used? Shimano HG71, which is a 6, 7, and 8 speed chain. My 1987 Fuji Del Rey is also a 6 speed. Same chain, the Shimano HG71. My Trek 750 and Specialized Sirrus are 8 speed - same chain. My MTBs are all 7 speed - same chain.

In fact all 14 of my bikes are 6, 7, or 8 speed. They all use the same chain and a Shimano HG71 is my standard. I keep one spare chain and know that it will fit all of my bikes. I'm not even sure I could buy something that says it's a "6 speed" chain. They typically advertise them as 8 speed, but they also fit 6 and 7 speed and most of them say that right on the packaging.

This is a ridiculous discussion that will do nothing to help anyone coming into this thread later on. The OP already knows he can use 6-7-8 speed chains on his bike, and anyone reading this in the future will just Google it and discover the same.

What do you not understand that chains used to be wider?

How about this? I will send you a vintage 6 speed chain as long as you agree to ride it on an 8 speed bike until it is worn out. Then you can report how well that worked and how smart you are.

Thanks for the history lesson, but nobody's talking about vintage chains. We're talking about a chain that someone would buy now to put on their 6 speed bike. They OP upgraded to 7 speed, but he would have used the same chain if he left it 6. And as anyone that Googles it will find out, 6-8 speed bikes use the same exact chain. I'm not sure anyone makes separate size chains for 6, 7, or 8 speeds, do they? Is there a 6 speed chain you can buy that is different than an 8 speed chain? I'm guessing no.

No Jeff, we are specifically talking about the original wide chain Gene's bike came with, which was too wide to work with 7, speed. So I gave him a friendly reminder to make sure he has a narrow chain.

Then you opened your big mouth. Which it turns out you opened because you can't read.

You can apologize now.

While we are on the chain topic, is that KMC Z-6 also considered stiffer laterally as was the vintage Sedis style 6 speed chains that were 7.3mm in width? Occasionally I have had freewheels that didn’t like a somewhat wider gap from the upper cage pulley as is sometimes the case with some vintage Suntours, and the 6,7,8 speed modern Sram that I like didn’t shift satisfactorily.

He can correct me if I'm wrong, but I'm pretty sure he wasn't going to try to use the old original chain, with the new freewheel. I think he said he replaced it with a SRAM 6-8 speed chain.

This is exactly wrong. The comment that got this whole thing going, way, way up the thread, was...

The ORIGINAL CHAIN, on a 1985 bike would BY DEFINITION be a VINTAGE CHAIN.

Please stop. You misunderstood Kontact's original post. That's fine, happens all the time. But you keep doubling down on the mistake. Just stop.

Fair enough. Your original question, though, was about hub width and fitting a 7-speed freewheel - nothing about chains. Were you thinking about using the original, vintage chain, and he set you straight? Or did you already know to use a new chain?