Tires: Staggered tires, e28 bmw, rim width

Question
I am wondering if I can run 225 45 r17 up front and 245 40 r17 in the rear all on 17 x 8 rims on my e28 BMW  I know they fit and steer fine .I need to know if it is okay to run the staggered tires on square rims?Thank for your time.

Answer
Andy,

Typically, when a vehicle manufacturer uses a staggered fitment, the wheel widths are different - and sometimes so are the offsets.  So be very careful taking a clue from other vehicles about what will fit - or not.

The second part of this puzzle is that you can find charts that will list the allowable rim width range for tires by size.  Tire Rack has those in their "specs" section for each tire line.

In the case of 225/45R17, the allowable rim width are 7" to 8.5, and for 245.40R17 it's 8" to 9.5".  So you are good there.

And the last part of the puzzle - clearance.  Unfortunately, no one publishes a list of how much room there is in the fenderwells for all the vehicles produced.  But you can get hints at it.  For example, Tire Rack lists that size combination - so there are obviously wheel offset combinations that will work.  

So on the surface it would appear this works - but I remind you.  Be careful as offset plays a HUGE role in this.  Some trial fitments would be a good way to determine this.