Glass fibers added to RIM urethanes provide materials which offer the automotive engineer a broadened performance spectrum. The composite materials are stiffer and have a lower coefficient of thermal expansion than unreinforced urethanes. These attributes have been beneficial to the growth of the use of plastic materials over the past thirty years.High pressure RIM process equipment for the newer material systems can be designed to handle glass fibers. Each process equipment system must be analyzed in terms of the effect of glass fibers on the system's components.Performance comparisons with other automotive elastomers, such as injection molded thermoplastic urethanes and EPDM compounds, show that glass fibers provide similar benefits to all of the competitive material systems. Comparative data describe how tailoring of the elastomers is possible and desirable in order to meet current automotive fascia guidelines.