For the devulcanization of passenger car tire rubber, SBR is the most critical component. A screening study of different devulcanization aids based on amines and disulfides let to the conclusion that the most efficient devulcanization aid for this polymer is diphenyldisulfide, DPDS. BR acts similar to SBR and can be devulcanized efficiently with DPDS under comparable process conditions. NR is a non-critical component in the tire blend and will be devulcanized sufficiently under the chosen circumstances. The devulcanization behavior of CIIR is different: It will not effectively devulcanize in the temperature range of SBR and BR, but requires a higher temperature for a significant decrease in crosslink density. After fine-tuning the devulcanization process for whole passenger car tire rubber, this material can be devulcanized efficiently up to a degree of more than 70%. The presence of silica and silane hampers the reduction in crosslink density in the devulcanization process compared to carbon black filled tire rubbers.