Originally Posted by
abarth
Scozim just dropped off an 58cm Ironman frame set for me. The serial number is N4P0072. So it was build in 84, and probably sold as an 85 model. My question is, does the early Ironman has the same frame geometry as the later Ironman?
In a nutshell, no. Just about everything changed over the course of the 5 year run of this model (as a Centurion). Your 58cm should have parallel 74 degree angles. Eventually, the head tube got slightly steeper and the seat tube got shallower. The wheelbase and top tube length shrank slightly over the years. Fork rake and bottom bracket height also decreased. The only thing that appears to have remained constant was the chainstay length.