Red Clover Components
  • Home
  • About Triplizers
  • Store
    • 144 BCD Triplizer
    • 122 BCD Triplizer
    • 122 BCD Conventional Chainring
    • Triplizer Bolt Kit
    • The Freewheel Key
  • Installation Notes
  • Gallery
  • Blog
  • Useful Links
  • Contact Us

Triplizing a Campy Double: You Pays Your Money and You Takes Your Choice

5/4/2014

13 Comments

 
In my opinion, a triplizer ring is the best way to add a third chainring to Campagnolo cranksets—or Campagnolo clones—that use the old Campy 144mm bolt-circle diameter. No surprise there, since I’m just completing a first production run of 144 BCD triplizer chainrings based on a similar but no-longer-available ring once manufactured by TA (see preceding post).
Picture



Here's Nuovo Record crank fitted with a  conventional outer ring made by TA, a TA triplizer ring in the middle position, and a TA granny ring bolted to the triplizer. Note how the "arms" of the triplizer ring are slightly wider than the crank spider arms themselves. This shows most clearly at the arm in the 9:30 position.

Thanks to Bob Merrill at The Freewheel Spa for the photo.





But I will point out that there’s also another well-established method of adding a small granny ring to 144 Campy crank arms: You can have the drive-side crankarms drilled and tapped to receive special conversion bolts that make it possible to mount a small inner ring.

Bob Freeman at Elliot Bay Cycles in Seattle (elliott baybicycles.com) has been doing this conversion for the last twenty years, and has a reputation for doing great work. A nice step-by-step pictorial of the conversion process is available at https://www.flickr.com/photos/8379107@N03/sets/72157622574585267.)

[Update as of November, 2018: Although Elliot Bay Cycles closed for good in September of 2014, Bob is still drilling cranksets in his home shop. He can be reached by email at rdf1249@aol.com. He's also offering CNC-machined 30-tooth rings for stock Campy triples in the original 100mm BCD.]

Tighter Spacing
In one important respect, Freeman's approach is an improvement on factory-made
Campagnolo Record triples, which were manufactured from about 1973 until the mid-80s. Those original Campy triples used the same basic design and mounting-bolt system, but were drilled for inner rings with an oddball 100mm BCD.

Rings in that size were available only from Campagnolo, and only in a 36-tooth version. Framebuilder and machinist Jim Merz later produced aftermarket rings in sizn to 31 teeth. (For an interesting look at the history of crankset design—and why Campagnolo, among others, once seemed to have so little interest in offering reasonably low gearing—see http://janheine.wordpress.com/2011/09/07/history-of-aluminum-cranks.)


But when mounting bolts are tapped into an existing double crank, their placement is somewhat flexible. It's possible to stay with the old Campy 100 BCD standard if originality is the goal, although in that case it would probably be better to find a factory-produced triple. The old 84 BCD standard used by Stronglight and SR until the mid-1980s is another option, and will allow use of inner rings as small as 28 teeth. But the most convenient option by far is to drill for the modern 74 BCD standard, which allows the modified crank to accept a wide range of currently-manufactured chainrings in sizes down to 24 teeth.



Picture




A factory-drilled Record Triple, made for the exclusive-to-Campy 100 BCD inner ring. Note how the fluting on the crankarms stops short of the bolt holes.

Photo lifted from Ebay.




Things to Think About
As best I can judge (but remember, as a guy who make triplizer rings I'm hardly impartial), here are the pros and cons of the two approaches:

Cost: If you buy it directly from me, a 144 BCD triplizer will cost you $102. You’ll also need an inner chainring--which will probably cost about $40 if you buy one new--and a $20 set of comventional chainring bolts and 3.8 mm spacers. The inner ring is a stock item--no need to modify it in any way.


[Another update: For the benefit of future triplizer historians, if any, I'm leaving the prices mentioned in the paragraphs above and below as they originally appeared. But needless to say, it's not 2014 anymore. Current prices for my stuff appear under the "Store" tab on my web site. You'll have to contact Bob Freeman directly to get his]

Elliott Bay charges $40 for drilling and tapping the crankarm, plus another $40 for the specialized 6mm conversion bolts needed to fasten the inner ring to the arm. They’ll provide a generic inner ring in 28-30 teeth for $30, or a TA ring in 26-32 teeth for $60. That includes drilling and counterboring the holes in the inner ring from the original 8mm to 10mm, as required by the conversion bolts. If you later want to switch inner rings, you'll have to take the new ring to a machine shop and have it drilled out the same way.

In either case, you'll also need a new, longer bottom bracket. A modern square-taper Shimano cartridge bottom bracket--at $20-30--is the most economical option. If you have an existing cup-and-cone bottom bracket you're happy with, you may be able to find a longer spindle that will allow you to keep using it, although mixing and matching between manufacturers may take a fair amount of trial and error. (See the "Installation Notes" section of the web site for more detail on this.)

Flexibility: For the time being, at least, the 144 triplizer will be available only in the 42-tooth size. That should work for most users, but those who want a 44-, 46- or 47-tooth triplizer ring for an old-school half-step-and-granny setup are out of luck, at least for now. I may add rings in those or other sizes later if there’s enough demand.

A drilled crankarm, on the other hand, will accept any size middle ring. Crossover, half-step, step-and-a-half—any sort of wacky setup is possible as long as it’s based on standard-sized middle and outer rings.



Picture




Compare this photo (also shamelessly lifted from Ebay) to the image above. You have to look closely to see it, but here the bolt holes in the crankarms extend through the longer flutings, indicating that they were retrofitted into what was originally a double crank. The holes themselves are spaced for a bored-out 74 mm ring.

The extra mounting holes don't seem to have any effect on the strength of the crankarms of either the factory-drilled or modified versions. I've never heard of one breaking there.

Appearance: To all but the most discerning eye, a drilled Campagnolo double is pretty much indistinguishable from a factory triple.

The "arms" of a triplizer ring, on the other hand, extend slightly beyond edges of the arms on the crankarm spider, giving the assembly a subtly—but if you really look, noticeably—different appearance (see photo at top). That looks fine to me--but of course, it would. What really matters is how it looks to you.

Intangible, But Decisive for Some: Quite a few old-bike dweebs, including me, just don’t like to drill holes or otherwise permanently modify nice old bike parts. They (or I guess I should say “we,”) are happy to make any kind of nut-and-bolt modifications, as long as those changes can later be reversed. If you fall into that camp, you may prefer to bolt on a triplizer ring rather than having holes drilled in an original double.



13 Comments
scott victor
5/6/2014 12:19:24 am

RE: Cost. Do you not have to get a wider bottom bracket as well?

Reply
Jon Vara link
5/6/2014 01:20:52 am

Hi Scott,
Thanks for catching that. Yes, you will need a longer bottom bracket with either a triplizer ring or a drilled and tapped crankarm. I've updated the original post to make that clear.

Reply
Mark Guglielmana link
3/17/2015 03:55:00 pm

Unfortunately, Elliott Bay Bicycles closed doors September 30, 2014.

Reply
Jon Vara
3/18/2015 11:51:17 pm

Hi Mark,
Thanks for that information, Mark--I had heard a rumor that the shop would be closing soon but hadn't confirmed it. I'll change the post to reflect that when I have a chance.
I would hope that someone will be taking over Bob's jig and drill press and continue to offer that valuable service.

Reply
Paul W.
11/19/2016 04:21:23 pm

My A. Duprat Universel crank has that same 100mm BCD spec.

Reply
Chris H
2/6/2017 12:16:52 am

Do you know when Campag introduced their triple? I ask because I spotted a triple on one of the bikes in the Louison Bobet museum in Brittany, and have always wondered whether this was a modification or one-off made at the time for Bobet

Reply
Stephen H
5/16/2018 10:05:15 am

Will the standard Campagnolo Nuovo Record front derailleur work with a triplizer?

Reply
Jon Vara link
5/16/2018 11:19:30 am

Yes.

Reply
David Finlayson link
11/24/2018 07:12:50 am

I don’t think a simple “Yes” is the answer. Every Front derailleur has s maximum gear range. The Record derailleur does not have a manufacturer published range, but it was specified for the original chain set, often configured with 52/36 extremes. That would be a “16T Capacity”.

Since Triplizing gains access to rings smaller than 36, it would be interesting to see someone test the true range of the OEM derailleur.

Campagnolo published specs are conservative anyways, for example, the Nuovo Record rear derailleur has a published maximum cog of 26T, but it has been widely and successfully used with more common 28T Freewheels.

Bianca M link
12/15/2020 12:16:50 am

Good sharre

Reply
sbarner
3/27/2022 07:50:15 pm

David's comment made me think about the strange inner BCD of the Campy triples. I always wondered why there only seemed to be 36-tooth inner rings available and why they only offered it with the older Record cups, which didn't seal as well as the Nuovo Record ones. The latter I believe was because the unsupported section of the spindle is shorter with the Record cups and Campy justifiably traded off better sealing for reliability. I'm thinking that the reason they never made a triple chainring under 36 teeth for this crankset was because they didn't have a Record series front derailleur that would work with anything smaller, and they didn't care enough about the touring market to develop one. Later of course they did, but not until the next generation came out in the 1980s (starting with Victory/Triomphe and I think late Gran Sport). Even if a Nuovo Record front derailleur cage bushing would clear the chain on an inner ring smaller than 36, it likely would shift terribly, especially with the non-ramped and pinned 144 mm BCD chainrings. I have a modified Campy NR crank on a tandem sporting a 30t inner ring, but I run a more recent triple derailleur with it and it shifts acceptably, though not to modern standards.

Reply
chune
10/4/2022 07:40:44 am

I am attempting to make a 46/32 double out of a campy record crank. Can you provide any recommendations? I am not aware of any triplizers with 46t so it looks like I will need to drill and tap. The easy route would be tap for 74 BCD and run it like a triplizer but mount the 46t ring on the inside of the spider. I don't think that would look that great. I could also use a ground down 53t ring as a bash guard/chainkeep to make it look a little nicer.

Ideally I would like to run the 46t ring in the outer position and use thinner spacers for the 74 BCD ring but it looks like the ledges of the spider would interfere with the shift. If I machined the lips down do you think that would work? Or would that weaken the structural integrity of the crank? I got the crank for relatively cheap so I am fine permanently modifying it.

Has anybody successfully separated the drive side crank arm from the spider? They appear to be fused somehow and not a monolithic piece like dura-ace stuff. That could be another (albeit more involved) route to take.

Reply
Jon Vara link
10/5/2022 08:39:22 am

I have never thought of installing a big ring on the outside, but I tend to doubt that it would work. Front derailleurs are designed to work in the opposite direction (right to left to go to a smaller ring, and left to right to go to a larger one. I think the forces on the chain would work against what you'd be trying to do.

I have heard of people grinding or machining the "ledges" off a crankset for various reasons, and it does not seem to me that doing that would weaken it significantly, but I have not do it myself and would not do it, because I don't like permanently modifying old parts. I would not try to separate a crankarm spider from the crankarm under any circumstances--it sounds like a recipe for disaster to me.

You might consider using a 42-tooth triplizer and a suitable granny with a bash guard in the outer position, as described in the blog post "Installing a Triplizer as a Compact Double." That did work for me. You would likely need an 11- or 12-tooth cog in back to get a reasonable high gear, though. I have often thought of making a 46-tooth triplizer for that very application, but have never done so because I'm pretty sure there's not enough demand for such a thing for me to recover the costs of production while I'm still in the land of the living.

Reply



Leave a Reply.

    Author

    I'm a chainring czar and editor in Cabot, Vermont. You know, where the cheese comes from.

    Archives

    January 2021
    December 2020
    March 2020
    April 2019
    February 2018
    September 2017
    August 2017
    October 2016
    March 2016
    March 2015
    November 2014
    July 2014
    May 2014
    April 2014
    December 2013

    Categories

    All

    RSS Feed