The offset of a wheel is the distance from the mounting surface of the wheel to the true centerline of the rim. A positive offset means the mounting surface of the wheel is positioned in front of the true centerline of the rim / tire assembly. This in effect brings the tire in to the fender well more. Conversely, a negative offset means the mounting surface of the wheel is behind the true centerline of the rim / tire assembly. This will cause the tire to stick out away from the vehicle.
To compare the effects of changing the offset and width of your wheels use the WheelOffsetCalculator Wheel Offset Calculator
Each wheel has a different bolt pattern, and some wheels even have 2 different bolt patterns which allow it to be mounted on a wider range of vehicles.
Most Bolt Patterns are represented in the following manner:
- The "4" indicates the number of holes in the wheel for the bolts to enter and mount the wheel onto the car.
- The "100" indicates the diameter of the bolt circle measured in millimeters or inches. 4 & 6 bolt wheels are measured from the center of one bolt hole to the center of the bolt hole directly across from it. On a 5 bolt pattern, it is a bit trickier to measure without special tools. Imagine a circle running through the centers of each bolt hole. You would measure from the center of one bolt hole to the imaginary circle that lays between the opposite two bolt holes.
Plus sizing your wheel & tire combination was designed to enhance vehicle performance and looks by allowing fitment of larger diameter rims and lower profile tires. The theory is that while making these changes, you keep the overall tire diameter within 3% of the original equipment tires. This is important because larger variances can cause problems with transmission shift points which can decrease fuel mileage. It can also confuse braking system computers which can even lead to brake failure.
Here's the rule of thumb for "plus sizing":
Increase section width by 10mm
Decrease aspect ratio by 10 points
Increase rim diameter by 1 inch
Increase section width by 20mm
Decrease aspect ratio by 20 points
Increase rim diameter by 2 inches.
This is not exact, but it will usually get you in the right ballpark. We always recommend consulting with the people you are purchasing the wheels and tires from to ensure fitment.
It is important to keep your wheels clean at all times. Your brakes will cause the wheels to heat up, and this heat in turn can cause any dirt or brake dust to cook in to the clear coat. If this happens, there's not a lot you can do besides having the wheels refinished. Protect your investment and keep your wheels clean!
Below are some simple instructions on how take care of your wheels:
- Do not use household cleaners or other detergents to clean your wheels. The best wheel cleaning solution is a mild soap and water solution (what ever you would trust on the paint of your car). Clean with a soft, un-abrasive cloth. Only on polished wheels can you use aluminum wheel polish. If you use this polish on chrome, painted, or clear coated wheels, you will only scratch or dull the finish.
- Do not use steam cleaners in automatic car washes.
- Do not use any tire cleaners on your wheels.
- Clean wheels when they are cool. Heat can effect the soap, causing it to dry on the wheel and become difficult to rinse off.
- Clean one wheel at a time. This also prevents the soap from drying on to the wheel.
- After the wheels are clean and dry, apply a coat of soft paste style wax to them. This will create a moisture barrier and help ensure the finish lasts as long as possible.
This relates to the center hole 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 this is the case, it is recommended that you use a hub ring. Hub rings are hard plastic or metal ring that fits between the wheel and the vehicle. This centers the wheel perfectly on the hub ensuring that there is no run out when the wheel is installed on to the vehicle. Without hub rings it is possible to get vibrations even if the wheel / tire assembly is perfectly balanced.
All alloy wheels should be installed using a torque wrench. This ensures that the wheels are not too tight or too loose. Check your vehicle's manual for correct settings. When you install wheels for the first time, you should re-torque wheels after about 100km to 150km (60 to 90 miles).
Alloy VS Steel
The main differences between alloy and steel wheels lie in their durability and strength. Most high-performance wheels are made of an alloy and composed of aluminum, and other metallic substances. By using alloy wheels, you not only improve the looks of your vehicle but also the performance. The extra strength provides longevity as well as effecting tire wear in a positive manner. The weight reduction will improve steering response and handling, as well as help improve acceleration and braking.
There is a good variety of ways of constructing wheels. Most alloy wheels are made in either one, two or three piece construction types. One piece is just what it says, a wheel made in a mold as a single piece. 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. They have a center, and inside rim half, and an outside rim half. They are bolted together using the highest quality fasteners.
Manufacturing method is very important in the overall quality and performance of a wheel. Here are the most common types of manufacturing techniques employed:
Considered to be the best manufacturing technique, forging allows for the compression of an aluminum billet (one solid piece of aluminum) into an aluminum wheel using over 13 million pounds of pressure combined with heat. This produces a wheel that is both stronger and lighter then your standard aluminum wheel.
A subset of forging is called roll forging. In this process, a metal blank is run through rollers with impressions sunk in to their surface giving the wheel its final shape. This allows the wheel to be produced with less aluminum, reducing weight but maintaining strength.
Low Pressure Casting
This is the most common form of rim manufacturing. Much like a casting, 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
Opposite to low pressure casting, the liquid metal is not poured, rather it is sucked into the mold using a vacuum. This reduces impurities making the wheel much stronger than a low pressure cast rim.
The hardware holding your wheels to your car is an often overlooked step when installing new rims. Most aftermarket wheels require different wheel nuts / bolts than what was used on the original equipment wheels. Wheel nuts and bolts have many different seats (where the nut touches the wheel). The 3 most common are acorn seat (conical), ball seat (radius), and mag shank seat. These differences along with different lengths and diameters makes hardware very confusing. Always check with the people who supplied your wheels for the correct mounting hardware before trying to install them on your vehicle.