The present invention is directed to a peroxide curable rubber compound containing a butyl rubber polymer, an olefin polymer of ethylene, at least one .alpha.-olefin and optionally at least one diene, and a high vinyl polybutadiene polymer. The present invention is also directed to a peroxide curable rubber compound containing a butyl polymer, an EP(D)M rubber polymer, and a 1,2-polybutadiene polymer.