Quote:
Originally Posted by Bouchedag84
God.
I've called 4 different shops now, including tirerack and I keep getting different answers regarding the staggered fitment. Some say I can use the stock front size on all 4 corners and others say I must use a different rear size because of the rear rim width. Not sure what the heck to do or who to believe. Kind of frustrating to be honest. And $1500+ isn't too exciting either :P
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The highlighted statement in your quote above is true...you CAN use the same size tires on all four corners...but if you have staggered wheels...then you need to use staggered tires. It all depends on what wheels you have...and we don't know which wheels you have.
Help us help you better...what size wheel are you thinking of mounting winter tires to? If all 4 wheels are the same size (17"/18"/19"?) then mount the same size tires on all 4 wheels. If you are mounting them on a staggered set of wheels (fronts are narrower than the rear)...then you'll also need a staggered set of winter tires.
You can look at the tire pressure label on the driver's door jamb for the BMW recommended tire sizes. The non staggered 17" & 18" tires are all the same on all 4 corners. The staggered 19" & 20" wheels have different sized rear tires (due to the wheels being wider). But if you have 19" & 20" wheels that are all the same size...then you'd run the same size tire on all 4 corners.
You can also google for a tire size calculator and you can see what the recommended tire size is for a wheel rim's width. For instance, one of my favorite tire size calculator is:
Tire Size Calculator - Tire & Wheel Plus Sizing
Again, if you input the front tire size...look for the recommended wheel width...if your rear wheel is wider than the recommendation...then I would NOT try to stretch a narrow tire on a wide wheel. It will also change the overall diameter of the tire and if the difference is greater than 3% (+/-) than the other axle...you could cause unwanted issues with DSC & xDrive or DSC-X (can't remember your model year).
I run a staggered set of 20" wheels (275/40/20 fr + 315/35/20 rear) in the spring/summer/fall...and a square set of 18" wheels (235/60/18 all 4 corners) in the winter.
Square 18" Winter Set-up & Staggered 20" Summer Set-up