Mark,
The Campagnolo triple crankset with the 36T inner chainring first appeared in the 1974 English Catalog 17 but they were available before then.
The number for the triple crankset was 1048/5
818 was the Triple Chainring Spacer for the 36t chain ring. It definitely screwed into threaded holes in crank arm spider. The thread size was about 6mm or 7mm.
761 was the Track Chainring Fastening Screw, same as for Pista chainrings.
819 was the Right Hand Crank Arm drilled and tapped for the 818 mounting spacers.
744/1 was the generic number for the triple spindle. The number listed for the 68mm BB spindle was 68-SS-120X3 with an overall length of 117mm. The extension from the RH fixed cup was 20mm.
Back in the 60s Campy listed a triple crankset using the standard 144 BCD chainrings with a 42T (later 41T) small chainring assembled with longer chainring bolts. It used the same BB spindles.
I have an almost new Campy crankset that was precision modified by a machine shop and it has a 28T small chainring. It looks like a factory job.
TA makes or made an adapter to use a smaller triple chainring with a standard double crankset. Someone else made an adapter too.
One problem to watch for with a triple on a frame built for racing is to make sure that there is enough clearance between the inner ring and the chainstay. An adjustable BB like a Phil is a good solution for spacing problems.
On triples, I figure on only using the small inner chainring only on the 3 largest freewheel sprockets and I don't try to use those sprockets with the large chainring.
Chas. Colerich Oakland, CA USA
Marc Winnikoff wrote:
> *Topic 1*
>
> Please weigh in on fitting a bike with an original NR Triple versus a
> converted NR Double.
>
> Monsieur Freitas pointed out that the conversion gives you many more gearing
> ratio opportunities. Other than that I have heard that the original NR
> Triples, which are press fitted, are prone to failure under heavy use. Are
> the drilled and tapped conversions more durable?
>
> I am constructing a "Randonneur" out of a '74 Raleigh Pro and am pondering
> if I go with an original triple or a conversion.
>
> *Topic 2*
>
> Please let me know what is the appropriate NR BB and axle length for a NR
> Triple for a 68 BB width (including cup thickness). Also does a conversion
> use the same BB?
>
> Thank you.
>
> Marc Winnikoff
> Santa Barbara, CA USA