>>1642123>which in a bike is negligibleI think you're underestimating the weight of the boiler, of the steam engine and of the 2 tanks.
But yes it should be able to meet the braking specifications with rim brakes. Here in Italy a L1e moped must be able to stop in no more than 17.8 meters from 40km/h with only the front brake to get approval (from the maker point of view)
The problem in every day use is that rim brakes tend to overheat easily in long descends, decreasing efficiency . I don't think it would be viable to add the contraptions necessary for steam braking
