go one size above for sidis, i'm 43 1/2 and wear sidi 45, with cyclefit inner soles. Sidi bullet were my choice as reccomened by the kiwy guy in there ( velodrome record holder i think). If you're not sure about the size just go into a shop and try them on then get them online if you fancy. If you don't have wide feet it shouldn't be a problem to fit in any make of shoe you want.
go one size above for sidis, i'm 43 1/2 and wear sidi 45, with cyclefit inner soles. Sidi bullet were my choice as reccomened by the kiwy guy in there ( velodrome record holder i think). If you're not sure about the size just go into a shop and try them on then get them online if you fancy. If you don't have wide feet it shouldn't be a problem to fit in any make of shoe you want.