| Good question Jon, afraid I can't answer it, but I was weighing my discs the other day to see which were the lightest so that they could be fitted to my mag wheel, I found there was very little difference between the latest Brembo semi floaters ala 748R etc, the Brembo full floaters ala 915SP etc and the EBC prolites. My lightest set turned out to be a set of Spondon fully floaters | 
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