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According to the web site:

https://www.wheel-size.com/size/bmw/3-series/2014/

2014 328 GT had among other options square setup with either 225/55/17 or 225/45/18. Total wheel diameter in the first case is 679.3mm, and in the second case it is 659.7mm. Difference is about 3%. Do they use different speedometer settings, or just ignore the difference? If they use different settings, could that be done in the factory only, or can be reprogrammed later on? My GT came with 17 inch setup, but I am looking into 225/45/18 winter tires and wheels and wonder, if it is doable.

Thanks._a_
 

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Unless I misunderstood your question, I think you're missing something. As long as the wheels are identical to each other there's no issue, it's only when you're trying to go staggered. The fronts would need to be within 1% of the rear. You're comparing two totally different sets of tires
 

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Unless I misunderstood your question, I think you're missing something. As long as the wheels are identical to each other there's no issue, it's only when you're trying to go staggered. The fronts would need to be within 1% of the rear. You're comparing two totally different sets of tires
Yes, I think you misunderstood his question. The 1% threshold you mention is regarding the suspension in general but the OP was asking about the odometer reading and the potential for misreporting both speed and actual mileage due to differences in circumference on the tire.

My understanding is that it should be possible to code that but I don't know for sure. :dunno:
 

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Flying monkey herder
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for an F34 225/45/18 is the wrong size. it should be 225/50/18. your speedometer and odometer will read high. the F34 is coded at the factory for the larger tires.

all of the F34 tire sizes are one aspect ratio higher than the F30
225/55/17
225/50/18
225/45/19
 

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Why go with lower aspect ratio tires for winter? The ride will be harsher. Just get standard size winter tires and move on.
Or if you must just live with the speedo difference for half the year.
 

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I just purchased a 2019 430ix Gran Coupe and it came with 225 45 18 tires, so the original poster could very well be accurate !!!
 

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Flying monkey herder
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8,163 Posts
for an F34 225/45/18 is the wrong size. it should be 225/50/18. your speedometer and odometer will read high. the F34 is coded at the factory for the larger tires.

all of the F34 tire sizes are one aspect ratio higher than the F30
225/55/17
225/50/18
225/45/19
I just purchased a 2019 430ix Gran Coupe and it came with 225 45 18 tires, so the original poster could very well be accurate !!!
the gran turismo (F34) and gran coupe (F36) use different specs
 
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