Rolling Resistance (RR) is an important parameter for a tyre: the lower
RR the better is the rolling of the car on the road, and as a result reducing fuel consumption and gas emissions into the atmosphere.
Normally to attain low RR for a tyre tread is not difficult; the difficulty
is to have low RR, high wet grip and good abrasion resistance
simultaneously. This effective compromise can be obtained by the use
of new solution SBR(SSBR) with high vinyl and statistical distribution
of styrene and butadiene into the polymer chain. This goal can
be achieved by the introduction of new modifiers and vinyl promoters
in the preparation step of SSBR. Together with SSBR,
in the compound preparation stage of the tread (that accounts for 55%
of the RR of the whole tyre as indicated in the enclosed figure)
a proper mixture of silica/silane has to be used in order to create
an accurate combination of a rubber with a high molecular weight
and a chemical link of the filler, being bonded to the rubber.

(see more about EU regulation on labelling of tyres)