Rubber components of a tire comprising a diene elastomer and at least 1 phr of reduced graphene oxide nanoparticles having a specific surface area of at least 700 m2/g, an oxygen content of no more than 6 at %, and a ratio of non-aromaticity to aromaticity ID/IG of at least 0.7 as determined by Raman spectroscopy. Methods of preparing such rubber compositions in an internal mixer for achieving good distribution and dispersion are also included.