Originally Posted by * jack *
OK, so after more research, I can answer my own question:
Columbus TSX is "superbutted" CrMo with continuous helical reinforcements.
It was an improvement on the SLX tubing, but was quickly replaced by the
Columbus PRX ribbed tubing.
I assume I couldn't find much info because it was a short-lived tubing line,
sort of an interim stage between SLX and PRX.
I'm still trying to find the date range that this tubing was in production,
so I can pin down the vintage of my Guerciotti.
This is what I know about TSX tubing. It is made of Cyclex steel, like SP, SL, MS, SPX, SLX and, indeed, PRX tubing; the last ones were Neuron and Brain (a Cyclex Cromo combo). In the development of better steels by Columbus, Cyclex was superseded by Nivacrom steel: MAX, EL, EL/OS, Genius, Nemo and Zona tubing. After Nivacrom came Thermacrom steel: Foco and Ultrafoco tubing.
TSX and PRX were the last developments of Cyclex steel, PRX being the most sophisticated. Now I have never seen a frame built with PRX tubing, but I have seen a fair number of TSX ones. I would say TSX is far more popular than PRX.
I would date a TSX frame to '91 or '92.
Hope this helps.