The invention relates to a tire of a structural combination of tire tread
and sidewall components with compositional limitations containing
minimal, if any, of in situ formed alcohol and methyl isobutyl ketone
byproducts. The tread component rubber composition contains
pre-hydrophobated silica reinforcement. The sidewall component contains
low unsaturation EPDM or brominated copolymer of isobutylene and
p-methylstyrene and may contain pre-hydrophobated silica reinforcement.
The silica reinforcement for said tread and sidewall components is a
pre-hydrophobated precipitated silica. The pre-hydrophobated silica is
prepared, prior to mixing with the elastomer(s), by reacting hydroxyl
groups (e.g. silanol groups) contained on the surface of a precipitated
silica with an alkoxyorganomercaptosilane or a combination of an
alkoxyorganomercaptosilane and a substituted alkylsilane or with a
bis-3(trialkoxysilylalkyl) polysulfide which contains an average of from
2 to 4 connecting sulfur atoms in its polysulfidic bridge to form a
composite thereof. The alcohol byproduct therefrom is removed from the
composite prior to its introduction into the rubber composition(s). In
another aspect of the invention, the connecting sidewall rubber
composition, and optionally the tread composition is free of
N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine antidegradant
(referred herein to as 6PPD) in order to prevent in situ formation of
methyl isobutyl ketone byproduct from the reaction of 6PPD with
atmospheric oxygen and/or ozone.