Which 2011 wheel? And what are the specs of this 2011 wheel? Min/max tire widths are determined by the width of the tire. You give no specific 20" BMW wheel. If you don't know which BMW wheel style you have...either decode your VIN...or go to one of the online part database sites and pull up the wheel diagrams and search for the wheel that you have.
- To decode your VIN (type in the last 7 digits): www.mdecoder.com
- To look up the 2011 wheels that were available for your car (type in the last 7 digits of your VIN...then browse over to the Wheel diagrams): www.bmwfans.info