Backspacing:
The distance from the mounting surface to the back of the wheel.
Bolt Pattern, Bolt Circle Diameter:
The Bolt Pattern is the diameter of an imaginary circle that goes through the center of the bolt holes. Examples are 4x100 mm, 5x4.5 in, 6x5.5 in, 8x170 mm.
Centerbore:
The size of the hole in the back of the wheel that centers the wheel properly on the hub of the car. Many aftermarket wheels will be drilled to a larger universal size, and uses hub rings to reduce the size to match the hub on the car for perfect centering. Generally speaking, a perfect hub size match and hub rings can be optional for vehicles that use lug nuts, but are absolutely required for vehicles that use bolts such as BMW, Mercedes, and VW.
Offset:
The distance from the centerline of the wheel to the face of the mounting surface of the wheel that contacts the hub. A simple way to understand offset, is the lower the offset, the more the wheel will stick out, likewise, the higher the offset, the more the wheel will tuck. For example, and Honda Civic generally uses around a +40mm offset. So if you put a +15mm offset wheel on the car, the wheel is likely to stick out about 1 inch.
First and foremost, wheels are purchased for styling the vehicle. You've got to like how they look. Second, decide on the build method and quality. The discussion of manufacturing methods above was intended to inform you of the different ways wheels are made. Choose the manufacturing method you want at the price you are happy with. Finish quality is important, so demand a nicely finished wheel. Finally, decide on the price. We realize there are many tradeoffs between the various features and price and that's why we carry a wide selection of wheels for every budget.
In most cases, using a spacer (of greater than 3mm thickness) or an adapter means you will be using a wheel that was not designed to fit your vehicle. Unless you get the advice of a professional, this can cause trouble. An incorrectly fit wheel almost always leads to excessive wear on suspension parts, poor ride and potential mechanical failure. In the vast majority of applications, we do not recommend the use of these devices.
Most aftermarket wheels are manufactured with a center hole that will fit a wide range of vehicles. The hub-centric ring is an installation tool used to help hold the wheel perfectly centered during installation. Use of a hub centric ring can help in reducing minor vibrations. Proper installation and torque sequence is required to correctly center a wheel with or without a hub centric ring.
Take the wheel to a dealer for inspection as soon as possible. Following an incident, immediately inspect the wheel for damage. If you see any damage do not drive on the wheel. If you drive the vehicle and notice any vibration, pulling or other sensation previously unnoticed do not drive on the wheel. You should take the wheel to a dealer for inspection whether or not you see damage or feel anything unusual. Your dealer can advise if the wheel(s) needs to be replaced.
Directional tires will have a rotation arrow branded on the tire's sidewall. The arrow indicates the direction in which the tire should turn. Unless they are dismounted and remounted on their wheels to accommodate use on the other side of the vehicle, directional tires are to be used on one side of the vehicle and are intended to be rotated from the front axle to the rear axle. If different tire sizes are used on the front vs. rear axle, the tires become location-specific and prohibit tire rotation unless remounted.
A staggered fitment is also referred to as a staggered application. Basically, it means that the wheels on the back of the vehicle are a different size than those on the front. Wider wheels are usually run on the back, for example a 19x8 on the front and 19x9.5 on the rear. This is typically done on rear wheel drive cars such as Infiniti G35, Nissan 350Z, BMW, Mercedes, Audi, VW, Ford Mustang, and others. Having staggered wheels or running wider wheels on the drive wheels means more grip on acceleration and from an aesthetic perspective, larger lips. A staggered fitment can also mean larger diameter wheels on rear, for example a 17" diameter on the front and 18" diameter on rear. Some examples of this would be aftermarket Acura NSX and Chevy Corvette.