Classic Lightweights UK
Portacatena (Chain carrier)
Author Peter Underwood
The Portacatena was introduced by Campagnolo in 1977, which is towards the end of the era we cover on Classic Lightweights. However,it is rare and an interesting addition to any machine if you are looking for that something special.
Portacatena mounted on Campagnolo 1010B rear end
Campagnolo worked with many teams in the development and testing of prototypes and the idea here was that a rider, when punctured, would change down from the sprockets onto the Portacatena and then all the team mechanic had to do was to whip out the punctured wheel and replace it with a new one in seconds. I guess the mechanic and rider had to work out a way of holding the machine with rear wheel off the ground and then change back onto the sprockets. If this wasn't done the rider would be left sitting on the bike spinning the cranks and trying to get the chain back onto the (smallest) sprocket.
Five-speed freewheel on six-speed axle and frame spacing plus Potracatena
So how does this device work? Campag ends designed for the Portacatena (1010B) had two holes drilled to enable it to be fitted. The Portacatena carrier fitted inside the rear ends and looked a bit like a segment of a sprocket with the teeth ground off although it was made of alloy. As mentioned earlier, the rider would move the chain onto this and off the sprockets. The down tube changer for this gear use had a small 'trip lever' which had to be released to enable the chain to ride onto the device, Without this a rider could end up with no drive at a critical moment - imagine changing to the smallest sprocket for the final sprint, misjudging and sitting there spinning the pedals with no drive at all!
Down tube-mounted Campagnolo gear lever with trip
The disadvantage was that this device came out when top riders were using six gears. However, the Portacatena rider had to give up one of these gears and resort to five gears only. Obviously the rider was at something of a disadvantage for a whole day's riding over the conventional set-up with an extra gear. One gear may not seem much but on modern-day bikes an extra gear from nine-to-ten or ten-to-eleven does make quite a difference in letting one be at the right cadence at all times no matter what the terrain, and an extra gear from five to six is of a much higher percentage. Another disadvantage is that neutral service vehicles may not know which wheel to give a Portacatena user and it would more than lose time saved if they had to return to the vehicle to get another wheel.
Rear end showing two threaded holes for mounting Portacatena.
See top image of reverse for mounting bolts and unit.
Another view of milled-out Campagnolo lever with trip lever
Six-speed plus Portacatena with seven-speed axle and frame spacing
(Thank you to Robert Freeman for the use of these images)
The simpler version of this, the humble tab brazed some two inches up the seatstay, has outlasted the Portacatena and is still fitted to steel-built machines to this day. It is especially popular on randonneur/audax builds. I have this little gadget (shown below) which is a chain 'rest' to slide on the seatstay, what puzzles me is that the taper on the body seems to be the wrong way with the larger diameter at the top. Perhaps it is meant to be used with the bike resting upside-down on bars and saddle - contravening 'The Rules' - and then slipping it on the stays.
Later versions of Portacatena could be clamped to the rear end to enable fitting to a bike without the special rear ends.
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