I don't think a steel Dahon fork will be compatible. I might be wrong but I think the steel forks have a steerer that's slightly shorter and fits the Vitesse and Speed frames whereas the Alloy forks have a longer steerer compatible with the Mu's slightly longer head tube. Or perhaps it's dependant on the headset stack height. . . actually that could be more likely since the Speed P8 looks to have the same frame as the cheaper Speed models but has an alloy fork. Not sure, but steerer lengths, ID and also the large bolt OD are different for steel and alloy fork.