I had a pair of Sidi shoes in the early 90s and they were a size 48, but they were a bit small and I generally wore them without socks. Sadly, my dog ate those in 1995. I got a pair of size 49 Sidi road shoes (Genius?) in ~2004 or so and they fit lovelily with socks. I got a pair of Sidi MTB shoes in ~2009, size 49, and they fit pretty much the same as my 2004 road shoes..