
I guess that solves the mistery.
For the Gv201 I used the measurement as taken in the geometry chart, which isn't clear because it measures fork lenght as projection on the steering axle. If the measurement is axle to crown then the angle varies lowering the front to 558mm indeed.
I guess Mondice used the 400mm measurement as drawn on the geometry chart so the actual axle to crown is slightly longer; I guess this can make sense because of the flip chip that may slightly change axle to crown length.This would make the axle to crown 405mm for 50mm offset that won't be enough to get to that number of stack...
Anyway they changed geometry chart more than once in the last 2 months so errors are a possibility;
my frame is on its way, with quite a bit of delay, I'll take the measurements when it'll be here, also I ordered the frame before the flip chip was a thing so I have no idea what it'll come equipped with

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