In Shimano shoes I wear a 42 or 8 1/2 US. In Specialized I wear a 41 or 42. Specializes has a bigger toe box so a tight shoes still fits. The Specialized MTB shoes I have are also a 42. In a MTB shoe like Northwave if you wear an 8 a 41 should give you plenty of room. Unless you have a wide foot then go with the 42.