Here is some anecdotal shoe size observations. I have been trying in vain to find some stock not too expensive road cycling shoes that fit well. (My home-made shoes are in the works, but that is a different thread!).
My feet are about 305mm long and 120mm wide. Here is a list of shoes by various manufacturers and how they fit (or don't):
Diadora Geko road 50: fits ok, a bit narrow in the sole. Duegi vintage 48: narrow sole, but somehow fits like a glove anyway. Sidi Genius 5 Mega 50: too short, too narrow, baggy upper, loose heel. Nike Altea II 49: too short.
Non-cycling: Nike running 49.5 (15): good fit Diesel casual 49 (16): perfect Giro casual 50 (15): good fit
So WTF? Why can't manufacturers use a sizing system based on what length foot they are supposed to fit?
Diadora Geko road 50: fits ok, a bit narrow in the sole. Duegi vintage 48: narrow sole, but somehow fits like a glove anyway. Sidi Genius 5 Mega 50: too short, too narrow, baggy upper, loose heel. Nike Altea II 49: too short.
Non-cycling: Nike running 49.5 (15): good fit Diesel casual 49 (16): perfect Giro casual 50 (15): good fit
So WTF? Why can't manufacturers use a sizing system based on what length foot they are supposed to fit?
Because we live in an imperfect world <g>.
BTW, your Sidi Mega fit sounds like mine IRT loose heels. My feet are wide enough that the upper fit OK, but the heels were totally loose. The regular model in a half-size (which are, according to sources, built on the same sole length but are cut wider) works very well for me. IOW, if you like Sidis (I like the Gen. V buckle a whole lot), you might be able to get a pair that fits. --D-y
