Drillium Dude 

I was looking through the thread about that gorgeous green Presto and noted one of the Forum members wrote that he'd never seen a bike with a Portacatena attached. He also noted that he believed there was another kind of attachment for the Portacatena - the one in which the chainkeeper is attached directly to the dropout.

Being the friendly, helpful kind of guy that I am I would like to share a couple of pics of the screwed-in version. This is the later version; it came out around 1977/78. The 1010B dropout does indeed have two pre-tapped screw holes built in. The chainkeeper part screws directly into these two holes in the dropout. As you can see on mine, I have treated the chainkeeper crescent to some drillium (of course, right?). The earlier type - as on the Presto - was designed for the earlier 1010A dropouts (and later 1010B dropouts without drilled and tapped holes) and incorporated the attachment inside the dropout fork itself. The chainkeeper is a little beefier, however, it has less overall length than the screwed-in version.

In order to shift from the cogs to the chainkeeper, Campagnolo designed a special shift lever stop for this system. It incorporates two notches vice the little flick-out used to limit forward motion on the normal shift lever. The first notch limits the shift to the smallest cog. When the button on the right side shift lever is depressed the lever is allowed to move forward to the second notch, thereby allowing the chain to shift from the lowest cog to the chainkeeper. When setting up the derailleur limit screws, you have to put the shift lever all the way to the second notch and turn out the rear derailleur limit screw enough so that the chain is allowed to move onto the chainkeeper. Pull cable taut and tighten cable clamp bolt. Once the wheel is installed, shift the lever back to the first notch and the derailleur will shift the chain onto the smallest cog. Pretty neat little piece of kit, really.

Great little device for a couple of reasons: one, it makes removing the wheel and cleaning the drivetrain a breeze. Two, on a downhill you can sneak up on other riders while coasting - with the chain on the chainkeeper there is no drag on the freewheel and your descent is near-silent! Breakaway, anyone?





Sorry no pic of the lever arrangement but I am currently at my Flickr upload limit for July! There are some comprehensive pics of the mechanics of the shift lever on the Presto thread, however.

thirdgenbird

thanks for he lesson!

5cagm

Very cool, that thing is pretty wild and I had never heard of one before until now. I wonder how someone came up with that piece of mech.

frpax

Very interesting. I'd never seen or heard of that little doodad!

WNG

Wicked, I learned something new today! Thanks.

cudak888 

I've seen them talked about, and I've seen them loose, but this is the first time I see one where it belongs; and beautiful photos of it too. Thank you.

-Kurt

king*stink

Wow that thing is cool. Thanks for sharing

Elev12k

The post with the system on the green Presto >>>

https://www.bikeforums.net/showthread...1#post10577703

Rabid Koala

Thanks for posting, I'd never seen one before.

cudak888 

! - boy, did I miss that one. Surprising too, for I was all over the Presto when it was first posted.

-Kurt

Bianchigirll 

that is very cool. I would love to have one of those.

Drillium Dude 

Ironically, Bianchigirll, the first time I ever saw one was on an '83 Specialissima owned by a bike shop guy in Hawaii! They really are neat and functional, too.

bikerosity57

Been riding for 40 years and never heard of these!

noglider 

I remember when that thing came out. I liked it.

I wonder why they didn't catch on.

Gary Fountain

The lever is interesting also. There is a 'trigger' under the rear gear lever. Pull the trigger and this allows the rider to move the derailleur past the outer stop aligning the small sprocket so the chain can be de-railled onto the 'C' chain holder. This allows the rear wheel to be taken out and replaced by a race mechanic when a flat occurs. The mechanic then pushes the rider off while the rider de-rails back onto the appropriate sprocket.

Here is a poor photo - you can just see the trigger under the gear lever.

5cagm

This thing is seeming more and more genius with more photos and info. Thanks Gary. I too wonder why it never caught on. It seems like it would have been a great thing during a race, especially if you had a flat.

vjp

It never caught on because you loose a cog space with the device. Mid 70's spacing was generally 126mm for 6 speed and with the Porta Catena you would only have room for 5 speed. Bianchi changed their spacing on the Specialissima frames to 130mm in the late 70's early 80's to accommodate the device AND 6 cogs but it wasn't sold as OEM equipment on complete bikes so it didn't get the traction it needed.

vjp

cudak888 

I'm not quite certain that was the big picture - I would think that racers would be mighty uncomfortable to slam the right hand lever down during a race's final sprint, only for the lever release to engage (and thereby engaging the Portacatena - durin a full-tilt sprint).

-Kurt

rat fink

That's a great idea. It reminds me of better version of a feature my Super Strada has. If you look closely at the chromed part of the seat stay, you can just see the peg:



It's designed to accomplish a similar task. Basically, you shift to the highest gear, then pull the chain up and drape it over the peg. It's a great feature I wonder why more frames don't have it.

The Portacatena design would be and awesome addition to current racing bikes. Instead of going to 11 speed, they could just keep the 10s spacing on the cassette, but make the non-drive side of rear hubs narrower to accommodate.

beech333

Drillium Dude: Do you have any pictures with the chain off of the portacatena? I'm just curious if it is smooth or if it has teeth to hold the chain. I don't know much about them, other than learning recently that one of my frames has holes for it.

beech333

I've seen a few of those, many on touring bikes, but the one on the Miyata that I recently had on CL looked like somebody forgot to remove the chain before riding. It was bent down and useless.

SJX426 

Great idea and I too have never heard of one until recently. If I had to make a choice between another cog and the functionality, I would pick the cog. Once you learn how to insert a wheel it is not a problem. I do like the peg on the chainstay. I have on on my RockHopper and use it every time. It does help.

I would be curious what the opinion is for those who are into touring. If they had to make a choice, which would they choose? I can understand the view of giving up the 11th cog for it however.

Beech333. It has to be smooth to be able to use it with the lever and the crank. At least the range of the SR DR is wide enough to accept both a cog or the Portacatena!

JohnDThompson 

It's smooth:


All of Campy's model 1010B dropouts came drilled for the portacatena, so you'll find them on many makes of that era.

cudak888 

I wouldn't be too sure of that. All of the 1010B's made during the Portacatena's time were drilled for them, but the holes were soon dropped along with the Portacatena.

-Kurt

Drillium Dude 

To answer those couple of questions, what Kurt says is definately true - not all 1010Bs were drilled for Portacatenas. I would also agree with his asessment as to why they never caught on (and I wince at the mechanics and resulting mayhem if indeed the Portacatena and not the last cog was caught on the final shift of the sprint!!!). I wonder when production of both the dropouts and the device stopped? I'm positive the dropouts were produced long after Portacatena production was halted.

John, great pic of the in-the-package Portacatena. I have one stashed away, but am over my Flickr posting limit for this month and haven't got it posted. Thanks for sharing that one as it clearly illustrates the chainkeeper portion - as seen from the driveside of the bike.

Note that John's pic shows one lever, the chainkeeper, two screws and the driveside shift lever stop plate (half hidden by the instruction paperwork) only. No second lever or stop plate - or the steel hardware - was included. This seems to hint that this was looked upon as a retrofit package (always asuming you were retrofitting to a new frame that had the drilled dropouts).

As a number of people have stated, you do unfortunately lose a cog. For most of us in the real world I don't think that's such a big deal, especially as it's the smallest cog. Now, if we were losing out on the granny, different story - especially for touring bikes.

The chain peg: mixed feelings. One, if painted, it quickly gets chipped from use. Two, the chain never seems to stay on well (if hung for cleaning or even travel). The Portacatena beats it for keeping a nice tension on the chain for cleaning/maintenance and also travel which are the main reasons I enjoy it. Plus, it has that "funky factor" that results in neat little threads such as these!

Gary - that's a gorgeous frame! Wow! Friends and neighbors, wouldn't you all like to see more pictures of that beautiful bike? I know I would... Is that a personally built frame?

Thanks to all for the additional comments, photos and factoids!