We always make spats in efforts to improve aerodynamics as we've seen them in the world of race car technologies. Unfortunately, their rarity in current models is based on car designers' preferences. Designers and manufacturers prefer fitting large wheels/tires in their wheel wells and visually line them up to the outer edges of the car body lines. Practical wheel spats require more clearances. The wheels would either have narrower tracks or require wider body lines. Currently the wheels are pushed out widest for the fashionable and preferred 'stance' look, for a more stable and 'purposeful' design.
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