Quote Originally Posted by Lisa S.H.
2) Rambouillets in sizes 54 and larger come with size 700c wheels (regular road bike wheels) In sizes 52 and smaller, they come strictly with 650B sized wheels (this helps prevent toe clip overlap on the smaller frames) Now mind you, 650B wheels are great, I almost got them myself. And they look nicely balanced on a smaller frame. 650B's are getting more popular and are no longer hard to get anymore. They were very popular for touring in Europe for generations. They just fit the smaller Rivendell bike frame dimensions better than 700c wheels.
Actually, I'm pretty sure that's not correct. As I understand it, in sizes 52 and smaller, the Rambouillets come with 26 inch wheels, not 650B wheels. 26 inch tires are quite common and easy to obtain.

A friend bought a Rambouillet (don't remember if it's a 50 or a 52) about a year ago and it came with 26 inch wheels, and that's what's specified on the website.

Now mind you, they could have changed the specs recently so I could be wrong.

My first thought is that you probably would be ok on a 54, especially if you put less fat tires than I put on! Remember, 2 cm difference between a 52 and a 54 is not very big a dfifference at all, and I have 1 1/4" to spare even with my fat tires. But a 56 would definitely be too tall to stand over comfortably for you.
If you're between sizes I personally think you would be better off going with the smaller size. I was measured by Grant and he told me I'd be fine with either a 57 or a 55 Romulus (another Riv model), and I ended up getting the 57, but sometimes I wish I had gotten the 55 instead. The Romulus fits me fine when I use tires up to 27 mm, with very little top tube clearance. If I use tires much larger than 27 mm I'm practically hitting the top tube when I straddle the bike. Plus, women generally have proportionately shorter toros, so for a frame size according to your pubic bone height, the top tube might be a little on the long side. I was able to make this work for me by using a shorter stem.

But I usually tell people, especially women (owing to our shorter torsos), that when in doubt, go for the smaller size.

Of course the BEST thing would be for you to test ride a 54 and a 52. Is there any Riv dealer near you at all, or somehow to test ride even just one of those 2 sizes?
What Lisa said !