A tire component comprising a vulcanized rubber deriving from a functionalized polymer defined by the formula I ##STR00001## where .pi. is a polymer chain, B is a boron atom, R.sup.1 is a bond or a divalent organic group, and each .upsilon. is independently selected from alkoxy groups (--OR), thioalkoxy groups (--SR), amino groups (--NR.sub.2), or phosphino groups (--PR.sub.2), where each R is independently selected from monovalent organic groups or two R groups form a divalent organic group, which forms a cyclic structure.