I know this is a "how long is a piece of string" question, but how far can you go past your "ideal" frame size?
I am 5'6" with in inseam of about 30". (I'm not quite sure about the inseam, but I used the ruler and tape measure jammed into the crotch method.)
I've never had a bike fitted before, but the guy at the LBS looked at me and said that I was about a 52cm. I think I complained to him how most of the previous bikes I bought second hand were too big for me, so I'm not sure whether he may have bumped me down a size to be on the safe side.
The thing is that height is a bell curve, so there are far more 54cm frames than 52. As I am going for second hand bikes, it gives me a far wider choice if I include 54cm frames in my search.
I tried a 52cm and a 54 cm frame in the shop IIRC. Both womens, as not 52 mens were in stock. The 52 fit me perfectly. The did feel very slightly longer, but I was still comfortable on it. But I'm not sure if I just was lucky that time.
Can I also just get a stem that is 2cm shorter than the existing one? Or does that mess up the geometry?