Forget bike weight: let's talk about the Portacatena!

[PATRICK MOORE]

http://campagnolo.wikispaces.com/Portacatena (Scroll down a bit.)

And of course Eric knows about it: http://campyonlyguy.blogspot.com/2010/08/today-history-lesson-portacatena.html

That's a really neat device, too -- wonder why it never became more popular. Much better to have a chainrest and easy wheel removal instead of another blanking cog. I wonder if I can jury rig something on the Ram I am building up. I am using (for the moment) seven speed freewheel wheels while the Ram has (I've been told) 132.5 OL spacing. 

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Patrick Moore, Albuquerque, NM, USA
For professional resumes, contact Patrick Moore, ACRW
http://resumespecialties.com/index.html
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[campyo...@me.com]

I have one, still in the original package. I've never had a bike with the proper dropouts ... or the space (see below).

The PC was reputed to be used by racers on descents--with the chain on the Portacatena, the freewheel would not buzz, and they could zip by their opponents undetected.

I suspect one problem with the PC was that if you parked the chain while riding (or when stopped( and then started pedalling, it would rip by the holder off of the dropout.  I haven't tried it, but that's my theory.

The PC also needs a fair amount of space between the smallest cog and the dropout. No biggie with a 5- or 6-speed freewheel, but beyond that the space inside the dropouts began to get pretty full. Check out the gap on amy modern bike, and you'll see that a holder that needs a chain's worth of space is no longer practical.

--Eric

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[Benz, Sunnyvale, CA]

I would think that with the prevalence of STI/Ergo/Rapidfire/Gripshifters and their lack of a lockout, it will be a significant liability when one attempts to upshift to a larger gear while pushing super hard and got...nothing but a freewheeling crank with its associated crash.

Bishop Bikes made a rando bike with an integrated portacatena:

http://www.flickr.com/photos/bishopbikes/sets/72157628089348263/

I saw that in person at NAHBS-2012 and it was pure sex on wheels.

[Marc Schwartz]

So elegant in design and fabrication.
Poetry as engineering.
Old Campy bits puts a lump in me throat and a tear in me eye.


Marc en Cruces________________________________________

[Jan Heine]

The porta-catena was a direct copy of the Nivex chainrest. When Tullio Campagnolo bought two Nivex derailleurs in 1948 from Alex Singer, he probably got the dropouts to go with them. Campagnolo turned the Nivex 90° to work with a bolt-on derailleur hanger and so create the first Gran Sport - the first parallelogram racing derailleur. After showing it at a few trade shows, he must have realized that the Nivex-style desmodromic twin-cable actuation would scare off many race mechanics, so he incorporated a return spring like Simplex already had on their archaic plunger-type derailleur. The immortal Gran Sport was born, which is the direct ancestor of all modern derailleurs. You can read the whole story here

http://www.bikequarterly.com/sample_articles.html

(first link under "History").

It appears that during the mid-1970s, Campagnolo's R&D didn't have much to do. Their components were made unchanged year after year. The biggest change, in the early 1970s, was to substitute a few steel bolts with titanium, and paint some parts black, to create the Super Record group. After that was done, somebody must have found those Nivex dropouts in a drawer, and thought: "Wow, that is a great idea!"

Instead of making  a new dropouts, they just drilled three holes into their existing ones, and created a bolt-on chainrest. Why wasn't it a success? I can only speculate that Campagnolo introduced it at a time when "more gears" was becoming the mantra. People just had moved from 5- to 6-speed, and 7-speed was on the horizon. Were they willing to give up one of those hard-won cogs? Neutral support could be another - the days when Campagnolo could dictate the equipment choices in the peloton were over, and with a Portacatena, you need a 126-mm-spaced rear wheel with a 5-speed (instead of the common 6-speed) freewheel.

How does the chainrest work? Very well. I have a Nivex on my bike, and Bicycle Quarterly's second tester Mark uses a hand-made chainrest on his machine. Even though I've only had one flat in the 18 months I've ridden the bike (thanks to the Grand Bois Hetre tires, which flat very rarely), it was great to shift the chain to the chainrest while rolling to a stop, then remove the rear wheel like a front wheel... There is no risk of ripping the chainrest off the dropout - in fact, the way to get the chain back off is to mount the bike cyclocross-style, and then pedal with the chain on the chainrest and shift back onto the cogs. (The cogs must be turning to allow the shift.)

My bike has a Nivex shift lever with a lockout for the chainrest, but Mark uses a standard Ultegra downtube shifter, with nothing to prevent an accidental shift onto the chainrest. I have ridden his bike, and done that on a fast downhill. Nothing much happens. You just shift back to the smallest cog again. Now if you sprinted out of the saddle and used STI to shift onto the chainrest, that might be a bit more dicey, but even there, I suspect it wouldn't be a huge problem. And of course, engineering a lockout into an STI/Ergo lever wouldn't be hard, if one of the big makers decided to resurrect the system.

Jan Heine
Editor
Bicycle Quarterly

Follow our blog at http://janheine.wordpress.com/

[Alex Moll]

Patrick,

Your attached photo (must be from Flickr?) is a pic of my 1980ish Colnago super. I think the chain rest idea is super slick, and works very well. The rear end is spaced at 126mm, and I'm using a regular 5 cog 14-24 Regina Oro freewheel. I know someone who is using an "ultra 6" freewheel in a similar era Gios - it apparently works fine. My Colnago come with the dropouts already tapped for the PC, I just chased the threads. I've seen a 1978 Colnago Super with the same dropout casting, but the holes were not yet drilled and tapped.

You may be interested to know that Campagnolo also made a single bolt version with works with any long horizontal dropout. I put one of those on my 1974 Bill Davidson, and it also works great. I'll try to attach a pic. Here's the link, just in case: http://www.flickr.com/photos/39151498@N07/8197764689/in/set-72157625243085418/

Cheers,

Alex

[Ron Mc]

no question, elegant is the word.  I looked at my 122mm dropout spacing - just no room at all for one of these - it's a shame.  

[Marty]

Chris Bishop in Baltimore has a bunch of photos of his effort to install one on a custom 650b Rando here. Lots of detail for both the single and double bolt version shown. (he used a single on the rando frame)  One of many amazing details he used on the bike, which one best lugged frame at the 2012 NAHBS.

http://www.flickr.com/search/?w=27337921@N03&q=Portacatena

[Ron Mc]

saw that earlier - very nice milling on the dropouts to make room for the portacatena.