Need some advaice which bike to choose and size please

kukui

I am 183cm (6' I guess), 32'' inseam or 34'' to the ground. I am very slim but I am a truck driver and need to move my butt and make at least 30-40 miles during weekend. I really want to start road riding, I consider Cervelo R3, Cervelo S3 and Cannondale Supersix Evo (all carbon). A guy in store told me 58cm would be good for me but I browsed the forum I don't know if 56cm would not be better for me. Please help, which bike would you choose and size?

fent

I'm also 6ft 1 with a 34 inch inside leg and looking at sizing for a road bike. I've been looking at some manufacturers websites and our height seems to be directly on the point of change between a 56cm medium large frame and a 58 cm large frame so you could possibly go either way. A large frame may be taller and longer than a smaller frame so I'd suggest trying the two if possible as the best fit could also depend on your upper body size. I am long in the body so I'd go for the large.
worth checking the specific geometry for the particular bike as I assume it can vary between manufacturers

mfin

58cm Cervelo will be too big. 56cm for those (or 54cm possible).