Custom wheels are one of the most common ways in which automobile enthusiasts customize their vehicles. Competition-oriented enthusiasts usually recognized performance benefits from switching to lighter, stronger, or larger wheels; appearance-oriented enthusiasts more often choose larger and more distinctive wheels, a trend made even more popular in the late 1990s and first decade of the 21st century by hip-hop videos.
Automobile racing enthusiasts tend to focus first on weight, depending on the discipline(s) in which they intend to use the wheels; rally events tend to be much more demanding and shift the focus to strength, whereas touring car racing and autocrossing are far less likely to cause wheel damage and may even provide greater rewards on the performance benefits of reduced wheel weight. In these cases, car builders will try to balance the advantages of a larger, wider wheel (less tire flex for better cornering performance) with the advantages of a smaller wheel (less unsprung weight, less risk of pothole damage on a street-driven vehicle). In the case of drag racing, the forces on the wheel are somewhat different and weight reduction is balanced primarily against the traction benefits of a wider tire on the drive wheels. In all cases, dual-purpose car owners need to either balance their requirements for a street wheel against their requirements for a race wheel or buy multiple sets of wheels.
For vehicles that are primarily street-driven, the advantages of aftermarket wheels are better performance and gas mileage, due to reduced weight and rolling momentum; these advantages can be lost if one chooses to use larger wheels. At some point, the performance advantage of larger wheels and reduced-profile tires meets the performance disadvantage of increased inertia and increased unsprung weight. This point will vary depending on the vehicle, style of wheel, and driving style; however, most vehicles will not see a performance increase when rims are increased more than two sizes from original-equipment specifications. Appearance-oriented enthusiasts may feel that decreased performance and an increased risk of road damage with oversized rims is a worthwhile price to pay for the look they want.
Newer aftermarket rims may be worth thousands of dollars, possibly as much or more than the vehicle to which they are attached; this does make them a theft target and led to the use of wheel locks, special lug nuts that frequently make it difficult to change a flat or have a vehicle serviced while rarely stopping determined thieves.