Originally Posted by
mechBgon
That's what I thought, too, Stumpjumper M2 or S-Works M2
... so it's probably 27.2mm (nominal) and I think that does put it at 1995.
I agree with the two M2 votes.
I had an 18" S-Works, the rear dropouts, the reinforcement under the downtube, and the welding all scream M2 ("Metal Matrix"). Nice frames, they eventually crack because they are pretty rigid (my M2 road bike cracked, I sold my M2 mtb after a few years).
M2 refers to the material, the S-Works (or not) simply the grade of parts it came with. Technically the S-Works was supposed to be nicer than the frames in bikes but I'm not sure about that, not in that era.
It's a great hardtail frameset, I regret selling mine.
cdr