The Ford Mustang is one of America's favorite muscle cars since the 1960s. In 1999, Ford introduced the eighth-generation Mustang, which, while based on the old Fox body platform, had all-new styling. The eighth-gen Mustang was made from 1999 to 2004. In 1994 the Mustang began using a different bolt pattern, which is still used on new Mustangs. The 1999 Mustang uses the bolt pattern introduced in the 1994 model.
A vehicle’s bolt pattern refers to the number of lug holes that are in a given wheel, and the distance that they are from each other. The figure is determined first by counting the number of holes on a wheel or the number of wheel studs on a hub. Most wheels on new cars use five lug wheels, though many older cars use four lug wheels. On a five-lug wheel, measure the distance from one lug hole to the space directly between the two lug holes across from the first one. A lug pattern of 5 x 4.5 means that there are five lug holes that are 4.5 inches across.
The 1999 Mustang wheel uses a 5 x 4.5-inch bolt pattern, so there are five lug holes that are 4.5 inches apart from each other. Mustangs made from 1994 and later use this lug pattern. Over the years, Mustangs have been produced with a variety of lug patterns.
In order for a particular wheel to fit onto a 1999 Mustang, it must have a 5 x 4.5-inch bolt patter. And beyond that requirement, not just any 5 x 4.5-inch wheel will fit on a Mustang. Just because the lug pattern is the same does not mean that the wheel will fit on the car. The other considerations are wheel offset (where the centerline of the wheel is in relation to the wheel mounting surface), width and diameter.
It is possible to change the lug pattern of a 1999 to something else in order that you may install wheels that feature a different bolt pattern. This is done by installing wheel adapters that have one set of holes that match the bolt pattern of the Mustang but feature studs that are a different wheel pattern. The adapter is bolted to the existing hub and then the new wheel is bolted to the adapter.
It is generally not recommended to install wheel adapters in order to install different wheels. The Mustang was designed by its engineers to use a particular wheel bolt pattern, offset and even diameter and width. The adapter can locate the wheel further then optimal from the wheel and place excessive stress on the hub and suspension.
