Cannot speak to a heavier brake on the 7000 vs 6000 AlKo Kobler, however, Al tells me that there is a difference in the axle itself, The 7000 has a thicker wall to the tube and the spring hangers have a different distance between them. Also the 6000 has 6 lugs, the 7000 has 8 lugs.
(My disclaimer, you know the routine, first cup of java of the day and Al is at his mom's so I cannot verify this, but, I am bout 80% sure I got it right !
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