255/45ZR17 on rims that currently have 235's on them

[CTJoe]

I have a 2000 540i that I just bought a set of Goodrich Comp2 AS tires for. The car originally came with 255's on the back, but for some reason, there are these awful Chinese Primewell 235's on all 4 wheels. This is probably a stupid question, but does that mean that the rear wheels were swapped out, and I'm stuck with 235's all around, or can I put 255's on the rear wheels? If so, would this be an improvement to having all 235's. Thank you!

[adxss2]

Unless the previous owner changed the suspension setup ( extreme lowering, wheel spacers, etc. ) the original tire size will always fit.
Not clear if the rims were replaced- you may need to buy new or find a OEM used set on eBay.

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