What a difference a
rim makes
Aftermarket wheels can
enhance performance, appearance of car
By
Jeffrey Fazio
Special Sections Writer
The
question of who invented the wheel still rolls through some people’s
minds. For the rest, the wheel questions might be: How good does it
look or how well does it handle?
Changed
much on the car since it was purchased? If not, chances are the
factory rims are still in place. Although the original equipment
manufacturer (OEM) wheels do the job, there are plenty of options, and
reasons, to upgrade them.
Gary
Mather, customer service manager of CJ’s Tire & Automotive
Service in Amity Township, said that there are two main reasons people
upgrade their OEM rims. The most common motive is appearance. The
second most popular reason is to improve the performance of the car.
Factory rims are probably about as attractive, and seem just as heavy,
as someone met on a blind date from an Internet personal ad.
Let’s
face it, society is trendy. Like a pair of hot-looking jeans, a set of
cool-looking wheels can catch the eye and get a heart racing.
Mather
explained that the latest trend in rims is size — the bigger, the
better. He suggests that when upgrading wheels, go as "high as
possible because they look better." A typical rim upgrade would
be going from an OEM 15- or 16-inch rim to an aftermarket 16- or
17-inch rim.
In
addition to size, Mather suggested the next thing consumers consider
is the finish of the rim. Rims are readily available in chromed,
polished or painted aluminum. Each finish offers a different type of
look and requires a different kind of care.
To
maintain your new wheels, Mather warned, "Don’t clean your
wheels while they are hot and avoid automatic car washes."
He
said some car washes even have warning signs about potential damage to
the finish of aftermarket wheels. He added that cleaning wheels while
they are hot could mark their surface.
If
the goal is to improve the performance of the wheels, Fabio Vlacci,
former rim and tire salesman and current SCCA Solo II and Hill Climb
competitor, advised upgrading to a wider, lightweight rim and,
depending on your comfort level, a taller rim.
Vlacci
of Mohnton explained that a wider rim will allow installation of wider
tires. This gives the car a larger "foot print," which
translates to more grip. When using a wider wheel, Vlacci pointed out
to be careful of the offset of the new rim.
The
rim’s offset is the distance from the hub’s mounting surface to
the centerline of the wheel.
"Using
the wrong offset puts undue pressure on the hub bearing," said
Vlacci. "The wrong offset could cause the rim to rub the brake
caliper or stick out past the fenders, which is illegal in
Pennsylvania."
A
lighter rim reduces the unsprung weight of the car, which increases
handling, Vlacci explained. Since weight is a basic factor in most
physics equations, reducing it affects all aspects of a wheel’s
performance. It is easier to accelerate and, more important, to stop a
lighter wheel than a heavier one.
When
considering a larger diameter wheel, Vlacci pointed out several things
to consider. A larger diameter rim means lower-profile tires should be
installed to maintain the same overall diameter. Lower-profile tires
have smaller sidewalls which makes the tire stiffer. The rigidity
attributed to lower-profile tires translates into less flex of tire
which means better handling. The downside of low-profile tires is ride
comfort.
"The
sidewall of your tires is the first point of your suspension,"
said Vlacci. "So a stiffer sidewall will allow you to feel more
bumps in the road."
Another
point Vlacci said to consider is how a larger rim and tire combination
can affect your speedometer. As long as the same overall outside
diameter of the tire is maintained as the car had from the factory,
there will not be a problem. However, when deviating from that
diameter, it starts affecting the accuracy of the speedometer.
A
taller tire and rim combination will travel further with each
revolution of the axle, thus throwing off the accuracy of the
speedometer. In contrast, a smaller tire and rim combination will
travel less distance, also resulting in an incorrect speedometer
reading.
Mather
points out that the other big risk of larger rims is damage. With a
large rim if you "hit something hard enough, you are going to
bend them," Mather explained. Since low-profile tires are less
flexible, more of the energy of a big bump is transferred to the rim.
Taking
all of this into consideration, Vlacci upgraded the factory rims on
his own car. He changed his factory 14-inch rims to a wider
aftermarket 15-inch wheel. Although Vlacci agreed that a 16- or
17-inch rim would look better, he didn’t feel it was worth the risk
of damage on local roadways. A better-looking rim designed for
improved handling is what he bought.
So
whether trying to catch an apex of a curve or someone else’s eye,
upgrading wheels can be an effective tool.
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