Originally Posted by
mmmdonuts
I'd say 56cm. Specialized runs big so a 58cm Roubaix is more like a 60cm conventional frame with a stretched head tube.
I agree with your second sentence. I ride a 61cm Litespeed M1. If I were on a Roubaix I would be riding a 58.
Hard to say about your first sentence since we don't have his measurements. Based on what the OP said, however, I still think the 58 is the right bike for him.