Using halobutyl rubber within the inner liner helps the tire to maintain proper inflation pressure. It is well known that a tire, which retains proper inflation pressure, displaces lower rolling resistance compared to conditions where it is under inflated. Furthermore, the tire needs the correct pressure to ensure that the tire performs well under safe conditions. ARLANXEO has completed tire survey's on both PCR and TBR tires from a global perspective that represent a significant portion of the worldwide tire market. Analysis of these tires focused on the tread, sidewall and inner liner. This presentation will highlight the results from our analysis on the construction and composition of the inner liner. In addition, the effects of polymer structure, filler type and plasticizers and their effects on key physical and dynamic properties of an inner liner compound will be explored .