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      10-31-2012, 08:07 AM   #14
TYC
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Drives: 2015 M235i TE
Join Date: Jun 2012
Location: Los Angeles / Toronto

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Another thing to keep in mind,is the x1 is not full time awd. The rear wheels get all the power unless slipping is detected, then power is is split between front and rear. So yes having a staggered setup would help handling. And no as long as the tire profiles are the same front a rear, then you wont have speedo or wheel speed sensor issues.

here is some math I have done

actual speed when speedo shows 60 mph
235/40/19 = -2.1% tire speed - 61.3mph
235/35/19 = +1.5% tire speed - 59.1mph
225/40/19 = -.90% tire speed - 60.6mph
245/35/19 = +.4% tire speed - 59.8mph
255/35/19 = -.7% tire speed - 60.4mph
265/30/19 = +2.3% tire speed - 58.6mph

So you see the staggered size that bmw recommends (F 225/40/19 R 255/35/19) will not affect your speedo or wheel speed sensors. Rim size for these tires should be no larger than 8.5" up front, and you should be able to up to 9" in the rear without issue. Always make sure to check with tire manf. for recommended wheel sizes for your specific tire.
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