I have a used set of X1 steel BMW winter wheels, trims and tyres for sale. I used them for about 16,000 miles and according to the last form I got from BMW in spring when I put the regular wheels back on they have 6mm tread inside/outside and 5mm centre. Don't need them as I have sold the car!
They are the Dunlop SP Winter Sport 3D tyres and absolutely brilliant in ice and snow.
Should be good for this winter before the tyres need replacing and the wheels themselves will last much longer!
Collection only from BMW dealer in Edinburgh although if you are elsewhere in the UK and genuinely interested I could find out if they can be shipped by BMW to your dealership (BMW are currently storing them)
Make me an offer...