Rubber compounds are complex mixtures of ingredients, including many mobile and volatile species. Exposure to the ultra high vacuum environment common to surface analytical instruments can therefore cause significant changes in a rubber surface and produce misleading and even erroneous results. In this work it has been shown that stable, representative x-ray photoelectron spectra could be obtained if the specimen was pre-cooled below a compound-dependent maximum temperature before exposure to the vacuum environment. Maximum temperatures were found to be -50°C and -70°C for two typical tire rubber compounds, a wire adhesion formulation and passenger tire tread, respectively. Effects of specimen preparation were further investigated. High resolution x-ray photoelectron spectra of specimens pre-cooled to -85°C and analyzed at -140°C indicated a correlation between the sulfur peak positions and the length of sulfur crosslinks in the rubber. Specifically, a linear relationship was found between sulfur 2p binding energy and the percentage of polysulfide crosslinks as determined by standard bulk solvent swelling analysis for three different rubber compounds based on two different polymers.