Winter Wheels & Tire Sizing

Orion12521 · 05-13-2023, 07:26 PM

I recently purchased a 2018 M550i with 664M wheels running a square setup 245/40/19 on summer tires. I'm thinking forward to winter and see that someone local is selling a set of 19" wheels with 225/40/19 tires. Outside of the speedometer being off -2.2%, is there a problem with running a set of wheels that is different from stock, if they have the same circumference for all four wheels? My understanding is that potential problems occur when front and rear are outside of a 1% difference.

faisalsid · 07-31-2023, 09:18 PM

From the looks for it you could actually increase your rear to 275/40/19, with so much power bringing down the tire size wont do justice.

What I am reading about winter, everyone is suggesting 255/40/18 square. I feel even for winter 245 should be just about right.

https://f80.bimmerpost.com/forums/sh....php?t=1035679

Mike 540 · 10-09-2023, 07:23 AM

Running the same tyres (with the same thread depth) is necessary for prevention of the x-drive problems. 1% difference sounds about right (I checked with BMW). In my country we can only run tyre sizes that are certified and listed in the tech certificate of the car. For me it is 245/40 R19 98H.

05-13-2023, 07:26 PM	#1
Orion12521 New Member 63 Rep 29 Posts Drives: 2018 BMW M550i Join Date: May 2023 Location: Iowa iTrader: (0) Garage List 2018 BMW M550i [0.00]	Winter Wheels & Tire Sizing I recently purchased a 2018 M550i with 664M wheels running a square setup 245/40/19 on summer tires. I'm thinking forward to winter and see that someone local is selling a set of 19" wheels with 225/40/19 tires. Outside of the speedometer being off -2.2%, is there a problem with running a set of wheels that is different from stock, if they have the same circumference for all four wheels? My understanding is that potential problems occur when front and rear are outside of a 1% difference.
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07-31-2023, 09:18 PM	#2
faisalsid Registered 0 Rep 1 Posts Drives: 540i xDrive Join Date: Jul 2023 Location: Calgary iTrader: (0)	From the looks for it you could actually increase your rear to 275/40/19, with so much power bringing down the tire size wont do justice. What I am reading about winter, everyone is suggesting 255/40/18 square. I feel even for winter 245 should be just about right. https://f80.bimmerpost.com/forums/sh....php?t=1035679
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10-09-2023, 07:23 AM	#3
Mike 540 Private First Class 37 Rep 164 Posts Drives: BMW 540i xDrive Join Date: Aug 2022 Location: Prague, Czech Republic iTrader: (0)	Running the same tyres (with the same thread depth) is necessary for prevention of the x-drive problems. 1% difference sounds about right (I checked with BMW). In my country we can only run tyre sizes that are certified and listed in the tech certificate of the car. For me it is 245/40 R19 98H.
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