Tire rims hold the rubber tire in place so that the vehicle can function. With so many sizes and styles available, you may wonder what the difference is, how rims work, and if the differences matter.

Rims are also known as wheels and are necessary for all automobiles, from passenger cars to commercial vehicles. Wheels provide two uses: they reduce friction and they provide leverage. The rim is an important part of the wheel because it rotates around rods that are called axles. Some friction is necessary to turn the wheels, and that is provided by the tire contacting the pavement. This helps the vehicle move along. The rim magnifies the amount of force applied, which provides the leverage. The amount of leverage depends on how large the wheel or rim is. This impacts performance for your vehicle.

Why Rims Matter

Many people focus on rims because of their aesthetic appearance. Change out the style or size of rims and you can create a new look. Bigger rims may make a vehicle appear more muscular or sportier while smaller rims create a low profile look.

Rims do more than just make your vehicle look good. A good set of car rims enhance your vehicle’s performance and provide a smoother ride. Changing the size of the rims on your vehicle impacts the alignment, handling, braking, and acceleration as well as the calibration of the speedometer.

Considerations before installing an aftermarket rim:

Make sure it fits in the wheel-well
Consider the correct backspacing, which is the width of the wheel and the location of the mounting plate
Ensure it matches the vehicle’s bolt pattern
Determine if there is an adequate selection of tires to fit
Make sure the wheels don’t rub anything on the vehicle

Working with professionals to choose new rims helps ensure that you select a design that is suitable for your vehicle.

Components of the Rim
Outboard face – this is the part of the rim that you see on your vehicle, while people often select it for the design, it also provides the structure for the rim.
Center bore – the empty hole in the middle of the rim that is often covered by a cap when the rim is on the car.
Plate – the section around the center bore that contains the bolt holes for the lugs. It connects to the axle seat and the rotor while everything else on the wheel connects to the plate.
Spokes – the long, thin structures that connect from the plate to the edge of the rim. They come in four-spoke, five-spoke and other patterns. They also provide part of the design element of the wheel.
Dish – the part of the wheel that connects to the spokes, the exterior of the wheel
Bolt circle – the circle that is created by the centers of the bolts
Valve stem – provides a hole to fill the tire with air, may be made of rubber or metal
Important Measurements of the Rim

When fitting a rim to a vehicle, there are two important measurements to consider. The first is the center bore, which is the hole in the middle of the rim. This fits the axle that is attached to the hub of the vehicle. It holds the wheel in place and is measured in millimeters.

The second measurement is a combination of the bolt pattern and the bore circle diameter. The bolt pattern is how many holes are in the rims that bolts or lugs attach to. Four- and five-lug patterns are common in most vehicles.

The bore circle diameter is the diameter of the circle measured in millimeters or in inches. For four-lug rims, you measure the two opposing holes. With the five-lug rims, you look for the two holes that are directly opposite from each other.