Originally Posted by
mmmdonuts
I'm 5'11" with the same inseam. My size on the Roubaix would be 54cm. I based it on that comparison.
You need to realize that the OP is not flexable, and a bit larger frame will allow him a more upright postion providing him with more comfort. This is a long distance bike so comfort is most important not an aggressive position.
He's riding a bike now with a TT about 1 1/2" longer than what the 58cm specialized will be, and a 60cm might be even better.