June 2020 - 16

On-vehicle versus
off-vehicle balancing
Spin balancing options for fleets.

When it comes to machine
wheel balancers, fleets have
the option to spin balance
wheels on the vehicle or off.
Off-the-vehicle balancing
requires a technician to dismount the wheel and transport it to a wheel balancer.
The balance machine spins the
wheel to determine the heavy
spot, showing the technician
where to place a wheel weight.
With on-the-vehicle balancing, the wheel doesn't
leave the truck or trailer. In
addition to balancing the tire,
it balances the hub and the
drum in relation to the truck's
suspension.
"The best benefit for
on-the-vehicle [balancing] is
that you're balancing everything from the hub, drum, and
[beyond], so it takes a lot more
of the imbalance out and it
does it all as one unit," says
Howard Williams, corporate

technical sales specialist at
Bee Line Co., an on-truck tire
balancing manufacturer.
Bee Line's Smart Balancer II
is an on-the-vehicle wheel
balancing system that uses a
touchscreen to illustrate the
location and amount of weight
to be added to the wheel.
"We like to [balance] on the
vehicle because we like to take
care of the whole product,"
Williams says. "We like to make
sure it's all balanced and not
just some of it, especially if it's
an older truck. They may have
the [original] drums on there
and it helps take care of some
of that imbalance."
Greg Meyer, product manager of wheel balancers at
Hunter Engineering, believes
on-the-vehicle balancing is
more dangerous.
"You have this big, powerful
motor spinning the assembly

"If a tire or wheel assembly is balanced
and after installation a vibration still
exists, the fleet may balance the assembly
on the vehicle in an attempt to balance
the whole wheel-end assembly."
Phil Mosier, manager of commercial tire
development at Cooper Tire

16 Fleet Maintenance | June 2020

»Having a wheel balancer
that can handle your fleet's
tires and address the tire life
issues you're most concerned
with for your bottom line are
important factors to consider
when selecting a system.
Photo courtesy of Hunter Engineering

up to [a] scary speed when
[the technician] is right there,"
he says.
Hunter Engineering's
ForceMatch HD Wheel Balancer
features SmartWeight technology which eliminates the need
to select the balance mode
and ensures proper centering,
reducing setup errors and service time.
When it comes to balancing
on or off the vehicle, it's a
matter of preference. Both can
address static and dynamic
imbalance issues, and both
can help prevent vibration and
irregular tire wear.
"When possible, off-the-vehicle
tire and wheel assembly balancing is preferred," says Phil
Mosier, manager of commercial
tire development at Cooper
Tires. "But there is still a place
for on-vehicle balancing. If a tire
or wheel assembly is balanced
and after installation a vibration
still exists, the fleet may balance the assembly on the vehicle in an attempt to balance the
whole wheel-end assembly."

rubber is scrubbed away. This is especially beneficial with tires that have been repositioned to drive
or trailer positions to run out prior to retreading."
Internal balancing compounds can be used on
all tire positions, improve vehicle ride, last the life
of the tire, can be reused, and eliminate the need
to keep inventory of different sizes of external
wheel weights. They also correct both static and
dynamic imbalances.
Chris Pourroy, director of national accounts
at IMI, says Equal Flexx also addresses tangential fore-aft (backward/frontward) forces, as well
as changes in the tire's footprint resulting from
changes in speed, load, or road conditions, known
as road force variations. For example, when hitting
a pothole or rumble strip in the road, a portion of
Equal Flexx stays in the footprint of the tire, dampening the impact like a dead blow hammer.
Isabelle Oliver, marketing product manager at
Magnum+, a Martins Industries brand, also notes
that "[external wheel] weights only balance tires
based on their condition at a fixed point in time
and as they wear, their balancing requirements
change, meaning the original fixed weights no
longer provide a proper balance."
Since internal balancing compounds re-balance
each tire whenever the vehicle is driven, technicians don't need to dismount tires or place them
on a computer wheel balancer for inspection.
Although there are many benefits to using
internal balancing compounds, fleets should be
sure to thoroughly research and test the products
before implementing.
TMC RP 214 advises fleets to verify that the
product will not affect either the tire or wheel
warranty, as well as assure the materials are
non-corrosive and non-abrasive to tire liners and
wheel surfaces. The RP also notes that balancing
materials can clog valve cores and create leaks
and that some materials are sensitive to moisture.
Balance rings
Installed between the brake drum and hub and
the wheel, balance rings are another method used
to balanced tires while on the vehicle.
Balance rings are filled with either free-moving
liquid or small metal balls and use centrifugal
force - similar to internal balance compounds -
to automatically balance the tire and wheel as it
travels down the road.
Bob Jessee, regional manager at Centramatic, a
hub and wheel balancer manufacturer, describes
their On-Board Wheel Balancer as a "once and
done" approach. Once installed behind the wheel,
balancing is permanent, he states.
To install, the balance ring goes on before the
wheel and is mounted the same way.
Centramatic's balancing rings can be installed
on all wheel positions and offer several part
numbers depending on the make, model, year,
wheel size, and wheel position, for a secure fit.
The balance media inside consists of small metal
balls, the size of BBs, in oil. Depending on the tire
position, the amount of balancing media inside
the device varies.
"The steer balancer, depending on the part
number, has between 12 and 16 ounces of balancing media inside it," Jessee notes. "The drive and
trailer balancer that is installed between the duals

June 2020

Table of Contents for the Digital Edition of June 2020