Originally Posted by gIzzE
I would go 225 all round. BMW recommend this, and BMW approve that Pirelli tyre, look on www.realoem.com
You can then put the slightly more worn rears on the fronts next winter and probably get 3 or 4 winters from them.
I do this with WRG2's (now replaced with WRA3's) and after two winters I have one pair with 6mm and one pair with 7mm so if I do the usual 5-6 k miles on them for this Dec-Feb then mine look set to give me 4 winters worth even working on changing them at the 4mm where winters stop working properly...