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Wheel Technicals
Offset
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.
Bolt Patterns
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:
4/100
- The
"4" indicates the number of holes in the wheel for the
bolts to enter and mount the wheel onto the car.
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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
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":
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Plus 1:
Increase section width by 10mm
Decrease aspect ratio by 10 points
Increase rim diameter by 1 inch
Plus 2:
Increase section width by 20mm
Decrease aspect ratio by 20 points
Increase rim diameter by 2 inches.
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- 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.
Wheel Care
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:
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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.
Centerbore
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.
Torque
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.
Wheel
Construction
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:
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Forging
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.
-
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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.
-
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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.
-
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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.
Hardware
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.
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