See also:

Tire condition
Inspect your tires frequently for tread wear, signs of damage and for foreign objects lodged in the tread. Check the tread depth. Minimum tread depthThe tread depth should not drop below 0.12 in/3 ...

Remove attached parts following use
Remove auxiliary mirrors, roof or rear luggage racks which are no longer required following use. Attached parts on the vehicle impair the aerodynamics and increase the fuel consumption. ...

2011 BMW 328 review
As BMW runs a war path with new model introductions — two gigantic, turtle-shaped crossovers a year, at this pace — they haven't forgotten where the profit margin lies. It's in the little 3 Series ...