The Alpe had an 853 main frame, 525 head tube and seat and chain stays...orange_julius said:If I recall correctly, that statement is a little incorrect: the Alpe d'Huez had an 853 front
triangle and 521 rear triangle. The Zurich is full-853 steel.
But the Zurich and MJ are not actually "full" 853 frames... they use Reynolds 725 seat and chain stays. They shape the chain and seat stays to make the frames ride better, and it's really hard to manipulate 853. So they use 725 for the stays instead.