Originally Posted by
Chris Pringle
The above answer should answer the OP's question.

Yes, but it misses the fundamental fact that fashions in frame size have changed a lot in the last 30 years. People used to ride big frames with short seat posts. When I went into a bike shop in 1978 they fitted me to 62 cm frame. If I went in to a shop today, they'd probably try to sell me a 56.