Hello, I am also new in this forum. I just notice that I have 255x18 for my X5 04 4.4i
and the spare was 235x17 too. Thanks for clear the ices.

Other question: I would like to change my wheel to 19" and I saw some one selling 4
wheel 285/45R19 I did talk to him and he say it is OK for my X5, but I talk to tirerack
they say that I should go with the 255/50R19 for front and 285/45R19 for rear.

Any one try 4 of 285/45R19 before for X5 04, would it have any problem ?

Any comment would be appreciated, Thanks