Anet A6 Z axis motor bracket with 30mm space for Plum Shaft Coupling

I bought Aluminium Flexible Plum Shaft Coupling for reducing the Z wobble.
But the item i bought is bigger in diameter than the stock (stock: 19mm, what i bought: 25mm ) There is 24mm space for the stock. I also added 5mm to my coupling so with my remix the space is 30mm in diameter.