Technical FAQ: Chain assembly, substitution of chainrings and cassettes into Campagnolo drivetrains

Different speed chains require different installation methods.

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Dear Lennard,

I’ve been replacing the chains on my bikes since forever. Never had a problem. Until now. (I’m fine, thanks). I had always noticed the little rings that stayed on the chain brake tool’s piston when the link was pushed out but never thought about them. I’m thinking about them now and I’m guessing that that “ring” is what keeps the plates from separating off of the link pin. (In my case a hollow links of a Shimano CN-HG901).

The reason this has made an impression on me is because I had to lengthen a newly installed chain. I used the left-over links from the very same chain to add two links. Should I have used a (second) Shimano master link instead of reinserting the hollow link pin? Or something else? I’m not finding any information on the Shimano site.

Which brings me to a second question: Is a master link half of a full link? If one is installing a new chain via the big ring /big cog length method, will I therefore need to add 2.5 links instead of the standard two links to get the proper chain length for my drive train?


Dear Robert,

Yes, you should have! You need to use a master link or a Shimano connector pin any time you assemble a Shimano chain. That damage you caused to the chain’s outer plate by tearing off a little ring of steel when you pushed a pin out is the reason that Shimano created its connector pins with leading guide pins that you break off after insertion. And it’s the reason other chain brands (and now Shimano as well) went to master links.

With any chain beyond perhaps 6-speed or maybe 7-speed, you are NEVER to assemble the chain with a link pin from the chain. There is not enough protrusion of the pin beyond the plates on such a narrow chain to provide sufficient security against prying the plate off of the end of the pin, especially under hard shifting from the front derailleur. A broken chain when pedaling under load is a recipe for crashing.

Scroll through the five illustrations of your CN-HG901-11 chain here to illustrations 3 and 4 (ignore that the “Shimano 105 DURA-ACE 11-Speed Super Narrow Road Chain” title on this page is screwed up; the CN-HG901-11 is Dura-Ace, not 105). You can see (1) that the ends of those pins are flush with the outer plate, (2) that the outer plate is concave at each hole to allow that, and (3) where the ring of steel that ends up on your chain tool’s piston when you push out a pin comes from.

Shimano specifies that you assemble any of its current chains with its connector pin or its master link. Unlike Campagnolo, which also required a connector pin with a leading guide pin from at least 9-speed chains and beyond, Shimano doesn’t require that the connector pin only be inserted into a virgin hole. With Shimano, you can insert the connector pin through a link that you previously pushed a pin out of, even though you tore that little ring of steel out of it. However, Shimano specifies that the connector pin should be the lead pin on the link (in other words, when that link comes over the chainring, the first pin coming over should be the connector pin).

Yes, a master link is half of a full link pair. So, if you are trying to add two full links when wrapping the chain big-to-big to determine its length (bypassing the derailleurs), you would instead add 1.5 links (not 2.5; it adds half a link, not subtracts it!) plus the master link to achieve that same length.

― Lennard

Dear Lennard,

In your response to Jon, you said that a standard 110mm BCD chainring couldn’t be mounted on a five-arm Campagnolo compact crank arm because of the 112 mm radius of the fifth hole behind the crank arm. I wanted to mount a 1x wide/narrow-tooth chainring on my Campagnolo compact crank, and of course Campagnolo doesn’t make one. That had me stymied until I thought of taking an aftermarket chainring (a Wolf Tooth Drop-Stop) and enlarging the fifth bolt hole by 2mm with a round file. There’s still plenty of contact between the bolt flanges and the chainring.

Do you see any problem with this solution?

– Geoff

Dear Geoff,

That will work. In fact, in response to my column last week, I received this letter:
“I think you’re right that inner rings smaller than 34 won’t fit. However, regular 110mm BCD rings do work if someone can’t find or doesn’t want to pay the price of Campy rings. A long time ago, a friend built a cross bike and wanted a 46-tooth outer ring, which Campy didn’t make. Our LBS used a regular 110mm BCD 46-tooth ring and drilled out the one slightly off-centre bolt. It worked fine for him, and I later bought the crank from him and used it for a while without any problems.

― Lennard

Dear Lennard,

I am reading your tech answers on VeloNews always with great interest, and as I cannot find anything on the following topic with a Google search, I would like to ask you.

Having a Campagnolo Chorus 12s equipped bike, it’s always a pain when it comes to changing the cassette, as it costs 150€ here in Germany (I guess it’s not cheaper in other parts of the world).
So, I have been thinking if it would be possible to change the freehub body of my Campa Bora WTO (not Ultra!) wheel to a Shimano 12s one (if available?) and use an Ultegra 12s cassette.

Is this something which can be done? And are these drivetrains as compatible as the 11s ones?

– Paul

Dear Paul,

Yes, you can put a Fulcrum-brand Shimano-compatible freehub body on your Bora WTO wheel (Fulcrum is owned by Campagnolo). I haven’t tried a Campagnolo 12-speed drivetrain with a 12-speed Shimano-compatible cassette. I believe that it would work, though, and here’s why.

No matter the brand of wheel or cassette, all 12 cogs have to fit into approximately the same width between the dropout and the spokes, in order that the derailleur doesn’t hit either. And the cog thickness will also be approximately the same, since the inner width of 12-speed chains is also consistent.

Supply chain problems over the past couple of years have hit bike chains particularly hard (pun intended), and cassette shortages have also been rampant. In order to deliver our bikes to customers rather than have them hang on the wall awaiting chains and/or cassettes, we have constantly had to mix and match brands and models of derailleurs, cassettes and chains. “Systems integration” is meaningless if you can’t get all of the components of the system! (The exception is SRAM, whose Flattop chains for its AXS road and gravel drivetrains have larger-diameter rollers than any other bike chain, so substitution of a non-SRAM chain with an AXS cassette is precluded.)

These mix-and-match drivetrains have generally worked fine. I have not tried the mixture you’re interested in, because we have had a particularly difficult time getting Campagnolo groups on any reasonable (or even unreasonable) timeframe during this period. However, there is not much wiggle room for different brands to have different spacing between cogs with that many of them jammed into that small space. That’s why I believe what you want to do will work.

― Lennard

Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder and purveyor of non-custom huge bikes , a former U.S. national team rider, co-author of “The Haywire Heart,” and author of many bicycle books including “Zinn and the Art of Road Bike Maintenance,” “DVD, as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”
He holds a bachelor’s in physics from Colorado College.

Follow @lennardzinn

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