Rim and Tire Pacakages

Alloy wheels, also known as rims are automobile wheels which are made from an alloy of aluminum or magnesium (or sometimes a mixture of both).

Lighter wheels can improve handling by reducing unsprung mass, allowing suspension to follow the terrain more closely and thus improve grip, however not all alloy wheels are lighter than their steel equivalents. Reduction in overall vehicle mass can also help to reduce fuel consumption.

Better heat conduction can help dissipate heat from the brakes, which improves braking performance in more demanding driving conditions and reduces the chance of brake failure due to overheating.

Alloy wheels are also purchased for cosmetic purposes although the alloys used are not corrosion-resistant. Alloys allow the use of attractive bare-metal finishes, but these require to be sealed with paint or wheel covers. Even if so protected the wheels in use will eventually start to corrode after 3 to 5 years but refurbishment is now widely available at a cost. The manufacturing processes also allow intricate, bold designs. In contrast, steel wheels are usually pressed from sheet metal and then welded together (often leaving unsightly bumps) and must be painted to avoid corrosion and/or hidden with wheel covers/ hub caps.

Alloy wheels are more expensive to produce than standard steel wheels, and thus are often not included as standard equipment, instead being marketed as optional add-ons or as part of a more expensive trim package. However, alloy wheels have become considerably more common since 2000, now being offered on economy and subcompact cars, compared to a decade earlier where alloy wheels were often not factory options on inexpensive vehicles. Alloy wheels have long been included as standard equipment on higher-priced luxury or sports cars, with larger-sized or "exclusive" alloy wheels being options.

Most alloy wheels are manufactured using casting but some are forged. Forged wheels are usually lighter, stronger, but much more expensive than cast wheels.

Aftermarket wheels

A sizable selection of alloy wheels (sometimes called "mags"—see below) are available to automobile owners who want lighter, more visually appealing, rarer, and/or larger wheels on their cars. Many people may think that large wheels automatically result in increased performance, handling and suspension. The allure of larger wheels is that they signify luxury, sportiness, or wealth.

Magnesium alloy wheels, or "mag wheels", are sometimes used on racing cars, in place of heavier steel or aluminum wheels, for better performance. The wheels are produced by one-step hot forging from a magnesium alloy.

They have the disadvantages of being expensive and not practical for most road vehicles. Aluminum wheels are often mistakenly called "mag wheels".