Originally Posted by
well biked
I don't know what the top tube length on the '83 58cm Expedition is, but I'm pretty confident it's not nearly 59cm like the 58cm LHT is. In fact, I'd guess the Expedition is quite a bit shorter. I'm just guessing, though.
But the LHT's are definitely sized with long top tubes, unusually so. Just keep that in mind.
According to David Mann's bike geometry data (displayed online at
http://hiddenfortress.org/geometry/index.html), a 58cm 1983 Specialized Expedition has a top tube length of 56.5cm. This would be approximately equivalent to a 56cm LHT (56.4-57.0cm). The 58cm LHT has a tt length of about 58cm. The 60cm LHT has a tt length of about 59-60cm. So, yes, be careful and maybe try to find some bikes with tt lengths in those ranges just to try for reference.