In 1976 Clement promoted their new puncture resistant latex tube formula.
Same weight as before, just more stretchy to allow for deformation of the tube instead of puncture. At the shop for which I worked back then, we were skeptical.
The new latex formula appeared in more models than latex tubes were used prior. Ted Ernst might know how far back, it was pretty early.
All the Clement Seta tires had latex tubes during this period, they were extruded and lap seamed at or near the valve stem.
The premium cotton tires had latex as well.
Bought my first seta in late 1973. With one set of wheels back then, had to change tires for a race, I saved fast for a true set of race wheels.
John Jorgensen
Torrance Ca