56 cm = 22 inches
58 cm = 22.8 inches
I wonder if it makes all that much difference to push the steering tube about 1/2 to 3/4 inch further from the seat to attain the 58 cm distance as opposed to my current bike size?
I know I'd be reaching further. Would reaching 1/2 to 3/4 inch further be as comfortable for 100 miles than what I am now? I don't know. I just don't know.
I did ride a 58cm Giant and the reach did not feel as comfortable to me as the LeMond. But maybe it all comes down to getting used to a longer frame and bypassing the discomfort for a couple hundred miles?