The innerliner is one of the most important components in a tire. This is due to the fact the innerliner must ensure tire inflation pressure retention. Loss on of inflation pressure will cause a decrease in tire durability due to excessive casing flexing as it rotates under load, increased vehicle fuel consumption due to increased rolling resistance, and loss of traction and wear performance. And this is even more important with the new generation of electric vehicles. The innerliner is based in halobutyl rubber. Bromobutyl has become the preferred polymer due to the better innerliner to tire ply compound adhesion. All of the new global butyl rubber production over the last ten years has been for bromobutyl for this reason. Butyl based compounds are difficult to process due to the need to isolate and prevent contamination of other tire compounds. Manufacturing operations are therefore designed for this purpose. However halobutyl compounds are relatively easy to process, they only require 2-stage mixing processes, extruder easily and when plied up with a barrier before tire building, handle well in manufacturing. This discussion will overview butyl and halobutyl rubbers, compounding, and impact on tire performance