yeah the 52cm should be the right size. I am also 5'7" with a slightly shorter PBH of 79cm. I just bought a 52cm LHT complete and find it to be a perfect fit. My stem has 3 spacers, which places the top of the handlebars about 1cm above the top of my Brooks Flyer. The Brooks is about centered fore/aft. I have about an inch or so of standover, and about a fistfull or more of seatpost. A plumbline from the area below my knee crosses just in front of the pedal axle when in forward horizontal position. The reach is comfortable on the hoods with arms slightly bent. My knees only hit the shifters if turning too sharply. No big deal. My only complaint is the stopping power is pretty weak. I'm probably going to soon switch to differnet brake pads. Otherwise, it is a great bike.