I think you will knee a 49 or 50 in the Alpinestars SMX Plus boot. I can wear 47 (12 US) and a 48(12.5 US). If you are a 13 get the 49 or 50. Should be okay.gjswt19 said:i tried the search but found nothing, i wear a size 13 in nike and was wondering if the alpinestars smx boots ran big or small or what. if anyone has any input i would apprciate it.