This refers to the center bore in the wheel that centers the wheel on the hub of the car. Since most wheels are mass produced, they have a large center bore to accommodate several different vehicles. If there is a vibration problem, it is recommended that you use hub centric rings. Hub rings are hard plastic rings that link the wheel to the vehicle. This centers the wheel and makes your wheel hub centric. Without hub rings it is possible to get vibrations even if the wheel and tire package is completely balanced.
The wheel offset is the distance from the hub mounting surface to the centerline of the wheel. There are three types of offsets.
Positive Offset A positive offset means the mounting surface of the wheel is positioned in front of the true centerline of the wheel. Most factory rims will have this type of offset.
Zero Offset When the hub mounting surface is centered within the rim, it is known as a zero offset.
Negative Offset If the hub mounting surface is on the brake side of the center line of the rim, it is considered a negative offset or "deep dish".
A wheel's bolt-circle-diameter is the diameter of an imaginary circle drawn through the center of the wheel's mounting-bolt holes. Different vehicle makes and models have varying bolt patterns.
If the pattern has an even number of mounting holes (four, six or eight lugs) simply measure from the center of one stud hole directly across the center of the wheel to the center of an opposite stud hole.
With a five-lug pattern, measure from the center of one stud hole to the center of the farthest stud hole, skipping the adjacent hole. The resulting measurement is slightly smaller than the actual bolt-circle diameter.
For example, a vehicle with a bolt pattern of (5 x 120) means this vehicle's hub has five bolts or lugs, which measure 120 millimeters apart from one another diagonally. Below is a chart on how to measure bolt patterns. Wheelfire.com has a fitment program that calculates this for you.
WheelFire has pioneered a fitment program that ensures a 100% proper fit for your vehicle. Our staff is constantly at work making sure wheel specifications are compatible with your vehicle. If you have any upgraded brakes or suspensions please contact our staff before you order.
Plus Sizing
Plus sizing your wheel and tire package is intended to enhance vehicle performance and looks by allowing fitment of larger diameter rims and lower profile tires. The idea is that while making these changes, you keep the overall tire diameter within 3% of the original equipment. If you exceed 3% you open the door to lots of other problems.
Always keep your wheels clean at all times this way you can protect your investment. Don’t let dust or dirt sit on your wheels this might destroy the finish. Never use steam cleaners or automatic car washes; they can damage your wheels. The best product to use is a mild soap, cleaning one wheel at a time. Rinse immediately, this way you don’t get a soap scum buildup. Always wait until your wheels are cool before cleaning them. After the wheels are clean and dry you may add a very light coat of wheel wax to protect your wheels from the elements.
Always use a torque wrench when installing your wheels, it's important to torque the lugs properly. Wheels are frequently over-torqued onto a vehicle's hub bore, which can lead to brake problems or even the lugs breaking right off the wheel.
The best way to torque your wheels is by hand, using a torque wrench. Your owner's manual contains the optimal torque specifications for your vehicle. Always re-torque after your first 50 miles.
Most alloy wheels are made in one, two or three piece construction types. One piece is a wheel made in a mold as a single piece of metal. Two piece wheels are made of two separate pieces center and barrel that are usually welded or bolted together. Three piece wheels are made of three separate pieces bolted together.
Wheels are manufactured in a variety of ways: Forging, Low pressure Casting and Counter pressure Casting.
Forging
This is the process of forcing a solid billet of aluminum between the forging dies under an extreme amount of pressure. This creates a finished product that is very dense, very strong and therefore very light.
Low Pressure Casting
This is the most common form of rim manufacturing. Liquid metal is poured into a mold and allowed to harden until the finished wheel is cool enough to be taken out of the casting.
Counter Pressure Casting
This method actually sucks the metal into a mold using a vacuum. This reduces impurities making the wheel much stronger than a low pressure cast rim.
