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Tyre sizes question

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Brucie1977 View Drop Down
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    Posted: 09 Jun 2019 at 9:36pm

I have a 320d M sport xdrive touring and need to chance the tyres shortly.

I am moving away from run flats and want to fit the Michelin Cross climate but they appear not to make the tyre in a 255 40 18 fitment? Front tyres are fine but my questions is if I were to go with the 245 40 18 would this annoy the xdrive system as I have been told diameter is key and only has a tolerance of 1mm...

Your help would be greatly appreciated before I make an expensive mistake.

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Tony View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Tony Quote  Post ReplyReply Direct Link To This Post Posted: 10 Jun 2019 at 3:56pm
Everything being equal*, the difference between 245 & 255 is 1.2% - so you'd have to change all 4 to ensure BMW are happy.

Personally, I wouldn't run 2 different tyre types on different axles either.

*manufacturers produce tyres to their own tolerances - so a 245 from one manuf. could have the same tread width as a 255 from another manuf.
2006 Z4MC
164k mile, Individual Ruby Black, Extended Champagne & Piano Black trim
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