When To Change Shocks
Proper maintenance is key to
keeping a vehicle safe and running
as long as possible. Yet too
often, shocks are overlooked,
and that can create problems.
Shocks “are a much more important
part of the vehicle system than
most realize, and as they wear
out, it isn’t long before something
else gives too,” says Jeff Schlump,
commercial sales at Gabriel Ride
Control (www.gabriel.com). “As
a rule of thumb, when changing
worn tires and doing regular maintenance,
the shocks should be
changed as well to prevent other,
worse damage before it starts.”
The company is the inventor of and
an industry leader in the design,
engineering, development and
production of automotive ride control
technology in North America.
FUNCTION
The suspension of a vehicle carries
the load and distributes weight
through the tires and onto the
driving surface, Schlump explains.
The vehicle rides on air or steel
springs to absorb vibration and
keep it relatively smooth on uneven
terrain. The shocks control the
movement of the springs, keeping
them steady and in control.
“It’s this setup that allows a driver
to accurately ‘feel the road’
as they drive,” he says.
“As the shocks start
to wear out, they can’t
adequately control the
springs. As the springs
bounce all over the place,
so does the rest of the
vehicle. It causes a loss of
consistency in the tires’
contact with the road, the
work of the brakes and
the response the driver
feels from the vehicle.
“The extra vibration
allowed by bad shocks is
distributed throughout
the load to places that are
not meant to handle it,” he
continues. “It can cause
damage to cargo, lighting
components, onboard
electronics, refrigeration
units, etc. Anything that
can be damaged by excessive
vibration suffers when
the shocks wear out.”
EFFECT ON TIRES
Bad shocks also cause
“interesting wear patterns”
on tires, observes
28 Fleet Maintenance | October 2017
Gabriel’s Schlump. Once the shocks
start to go and the springs start
to bounce out of control, the tires
can’t maintain consistent contact
with the road. As they bounce
and vibrate while rolling over the
ground it causes unusual scuffing
on the treads of the tires.
“When tires display these bald
spots the phenomenon is sometimes
called ‘cupping,’ Schlump
says. “A tire that has started to
cup is definitely one that should
soon be replaced. Otherwise
the loss of traction will start to
compromise driving safety.”
Gabriel recommends that
whenever a vehicle is taken
in to replace the tires, the
shocks be changed as well.
“If tires are already showing signs
of cupping, the chances are the
shocks have started to wear down,”
he says. “Any time a vehicle is in
the shop is a good time to perform
other maintenance checks.”
If old shocks were the reason for
the tire wear in the first place,
replacing the tires will only be a
temporary fix, he says. The worn
shocks will continue to put unnecessary
strain on the tires and
the frame of the vehicle, “causing
damage faster than before and
shortening the lives of brand new
tires. Leaving the old shocks on
the vehicle ends up being a waste
of repair costs in the long run.”
REPLACEMENT TIME
The frequency of shock replacement
can depend on a lot of
factors, notes Gabriel’s Schlump,
including what kind of loads a
vehicle is transporting, where
it typically has to operate and
what kind of drivers are usually
driving it. Shocks that are consistently
subjected to extra strain
should be replaced more often.
“In the end, it makes the most
sense to replace the shocks when
you replace the tires,” concludes
Schlump. “Even if the shocks aren’t
responsible for the tire wear, they
are much cheaper to replace than
tires, air springs or other expensive
hardware that can be damaged
by driving with bad shocks.
“It is better to foot the bill for some
preventative maintenance than
wait for more obvious signs of damage
that will be harder and more
expensive to fix down the line.”
» The frequency of shock
replacement can depend on
a lot of factors, including the
loads a vehicle is transporting,
where it typically operates and
the driver’s driving behavior.
Photo courtesy of Gabriel Ride Control
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