From what I know, the xDrive on the X1 is 60/40 (rear/front) by default.
When needed 100 % can be transferred to the front or rear as it is an intelligent system.
That keeps the BMW sport nature intact. Of course, it's different than AUDI's quattro. But it's a lot of fun in the snow being able to toss the rear around even with the DSC active.
Be carefull if you turn the DSC OFF because then you will see what's 60 % on the rear axle is all about
Fun but tricky sometime.
I'm running on 17" Dunlop SP Winter sport M3. They are great.