A polymeric article includes an electrorheological (ER) fluid in a polymer medium. In some applications, the polymer medium forms a body ply of a tire. The ER fluid can be incorporated into the polymeric article in a number of particular ways. The ER fluid may simply fill a pocket in the polymeric article or may be part of an electrorheological composite or electrorheological microsphere. The ER fluid is responsive to the application of an electric field to change the apparent viscosity or elastic modulus of the polymeric article.