I have been playing around with my Mirella project which has the steel 3 arm Capagnolo Gran Sport (or is it just Sport per Sutherland's?) crankset. I'll post more generally on the Mirella later.
In looking at the chainline I realized that the bike had a triple axle with a 53-42 double chainring. In the case of the Gran Sport, the smaller ring is rivetted to the larger ring. I somehow remembered that this 116 BCD chainring circle was the same as a TA Pro and, attempting to spin the straw axle into gold, got going on the idea of a triple conversion.
At Bicycle Specialties in Toronto I purchased a 36T chainwheel and the appropriate triple bolts. The result is that if you play around with the spacers you can get a nice triple setup on the Gran Sport. The bolts are just long enough. I don't think Campy ever made this crank as a triple or provided a 36 T chainring. Combined with a 14-26 freewheel my hope is this will give about the most versatile gear ratios that can be handled nicely by Campagnolo Nuevo Record derailleurs. Of course it is similar in ratio to a NR triple crank, but those are pretty steeply priced these days. Just an idea for that Cinelli B or Raleigh Gran Sport with this crank.
The TA Pro is certainly an uncommon crank in the US. It is hard to think it was really intended as a "pro" crank.
Bicycle Specialties is a TA stockist and buys directly from the factory. With the Cdn exchange rate I thought the prices very reasonable. Also the Mariposa frames look very nice indeed.
Joe Bender-Zanoni
Steamy Ann Arbor Michigan