I had a question about the larger wheels. Do they have to reprogram the car's computer to make sure the odometer and speedometer know what size wheels and tires you have? Otherwise, you would be way off on mileage and speed.

 

I haven't taken delivery of my new SQ5 yet, so I don't know if the Audi has different computer settings for different wheel diameters. My Porsche Cayenne does have this functionality, and I'm assuming and hoping that the Audi does also.

The impact of a larger wheel can be limited by choosing the proper tire size. For example, a 255/50 R19 wheel/tire combination has an overall diameter of 29.039". If you compare that to a 20" wheel, then you need to drop to a 45 series tire if you want to keep the diameter close. A 255/45 R20 wheel/tire combination has an overall diameter of 29.035", which is very close. The overall construct diameter can be manipulated by altering the aspect ratio or the tire width.