是阿~

The freehub need 1.85mm removed.
You can see in the 4th picture in my article, how much needs to be taken off the hub shell.

You need to remove all bearings and axle to get the freehub off and this is also required to dremel the hubshell.
I use 12-25 cassettes all the time.

This modification is to allow CS-9000 to work on a 10 speed hub. The use of CS-7900 with 1.85mm & 1mm spacers is standard for all 11 speed hubs.

感覺上花鼓怎麼切得畫圖來看...