I have learned that different bike manufacturers measure in different ways. Before I settled on my beloved LHT I really wanted a Salsa Fargo. That doesn't come NEAR small enough for me (though a salesman tried to convince me otherwise). There does not seem to be a standard when it comes to bike sizes and what they are called.
Height and inseam have very little to do with it. It's mostly the top tube length, which you don't mention at all.
Seatposts can be raised and lowered a LOT. Stem length and saddle fore/aft placement, MUCH less.
If you're comfortable on one of the 52 cm (or taller) bikes you found, buy it!![]()
Speed comes from what you put behind you. - Judi Ketteler
The best fit is going to come from a professional bike fitter at an LBS.
They take all kinds of measurements, plug them into a computer and it determines your frame size in the models you are interested in. You would find that you even take several different frame sizes from one company's stable of bike styles.
I am sure when you Googled choosing a bike size you also read that the tables are only a recommendation and that the best way to get the correct size is to have a professional fit. I know I did.
If you are looking at used bikes, my suggestion would be to choose a range and test drive any bike in that range. Bike geometries vary and just because one 52cm didn't work it doesn't mean another one wont be a good fit.
Enjoy your search and don't forget to post pictures when you find your bike!
Melissa has first right of refusal while she checks out the size options, but I have my mother's vintage 52cm mixte Peugeot UE-18, complete with racks, in the For Sale thread.
Shameless plug, but I've only a few weeks while visiting my mother to help her part with it. (And she IS reluctant, but has asked me to do this. She's 84 and her dance club challenges her enough.)
Owen
Some brands have weird sizing.. I am 5'7" and have a 47cm Felt that fits me just fine, but I'd previously tried other brands and anything <50cm was way too small. The felt has the "reach" of a bigger frame.
Anyways, my experience with Mixtes and sizing is that the seat tube length doesn't always tell you a whole lot... I have two adult sized ones, a 49cm and a 45cm, and the virtual top tube length is the SAME on both of them (about 53cm).. the seat tube angles are different though, so the have a different "feel" when riding either of them. I also have a kid sized one, with a 45cm seat tube, but the virtual top tube is only 49cm. There's no way at all I could fit on that frame... obviously it's not for me, but it's still small.
I've seen some mixtes with more reach than others, even with similar seat tube lengths.. but I wouldn't assume that just because a frame is a 52 that it will be too big. Figure out what the VTT is, and base your purchasing on that, rather than just the seat tube.