It is a ratio of the width. 40% of 225 mm v 45% of 225 mm. Are you just having the tires swapped on the original wheels? Better for winter tires would be something like a 215 on a 17" wheel or even a 215 on the 18" wheel. Narrower gets through the snow better. Have you checked winter setups on www.TireRack.com?
Then and Than are different words and they are not interchangeable.
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2006 330i Sonora w/ ActiveAutoWerke flash tune :-)
2004 330i ZHP Imola/NB - missed
2000 328i TiAg - gone but not forgotten
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Last edited by tturedraider; 10-06-2012 at 12:14 PM.