I am in need of snow tires and wheels for my 2012 X5d. Do I need to use the same size tire/wheel as the summer tires currently on the car 255 55 X18? Or can I use a 255 60 X 17 that I see advertised in the Classifieds here?
Start with tirerack.com and look at the sizes in 17" & 18" snow wheel/tire combos to compare. Tire Rack is conservative in their fitment, so if they show the same size or close, you're probably good. Most BMW wheels are 5x120 bolt pattern with something like 72.5mm centerbore, you can use what TR shows to get an idea of workable offset range. This can be helfpul for comparing: https://www.rimsntires.com/specspro.jsp If TR doesn't show smaller dia. wheels as an option, it may be that they found brake clearance to be an issue. With awd bimmers, it's important to stay close to the original front/rear overall rolling diameter (tire diameter measurement on the rimsntires compare page).
