| As already pointed out, it's not the static weight alone that makes the difference. For instance, I have narrow track race Brembo discs in both 290 and 320 mm sizes. As it's the disc itself, not the carrier that accounts for the majority of the weight, a narrow track disc reduces the weight where it counts most. The discs themselves weigh about the same as what you've measured, but they can now carry a thicker disc which last longer and dissipates heat better. Remember, brake systems are a science and very difficult to understand, well, certainly for me. | 
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