Recent societal developments such as the significant increase in female employment or digitalization challenge existing working time regimes. As part of its 2017/18 collective bargaining position, the IG Metall demanded a right to reduce working hours with partial wage compensation by the employer. Using data from the German Internet Panel we address the question of which groups among the working population support this demand. Our analysis proves the existence of traditional conflict lines: union members are in favour of the demand, while high earners and self-employed reject it. However, based on theoretical assumptions on value change, we argue that a second conflict line between libertarian and conservative values is important. Results show that support for this demand is influenced by individual preferences for a better work-life balance, especially high among young people and supporters of the Green party. This is an example of the union’s attempts to broaden its member base. Additionally, our analysis can contribute to the discussion of reduced working hours in the context of the Corona pandemic imposed short-time work.