Fleet Maintenance - 33

lug-based cracking if you have a lug design for
drive tires," Cohn says. "You can get cracking, heeltoe wear, alternate lug wear - the things commonly associated with higher torque."
Tires are usually considered one of the top three
expenses for a commercial fleet, Rabe says. That
means tires could have a major impact on the return
on investment for fleets considering operating BEVs.

Future tire technologies

As the new type of powertrain becomes more
widely tested, tire manufacturers are taking notice
and creating tires designed specifically to combat
the challenges presented by BEVs. They are working to combine existing technologies such as low
rolling resistance, which can help maximize the
miles driven on a single charge, with the durability to withstand the stresses of a BEV powertrain.
"In order to keep the wear impact from acceleration torque relatively low, it calls for modifications
to both the tread pattern design and the tread
compound," says Continental's Rabe. "Very low
rolling resistance is achieved by a blend of tread
compound, tread pattern, and the construction of
the tire - and the sidewall in particular - as well
as by keeping the overall weight to a minimum.
All of these measures need to be carefully coordinated in order to ensure that these tires retain
their very safe handling properties."
Rabe explains that improved rolling resistance
works in direct conflict with improved braking
distance. It's a case of conflicting goals, he says,
because less "grip" both improves the rolling resistance and reduces the braking performance. Tire
manufacturers can optimize new product generations with respect to all key properties using innovative technologies, helping lessen the effect of
these conflicting goals.
A longer BEV range with lower rolling resistance can only be achieved in compliance with
all safety aspects, Rabe adds. Braking distance,
handling, and directional stability must not be
overlooked. The challenge is to find the best
compromise between a safe braking distance
and low rolling resistance.
Tire manufacturers are also taking load carrying capacities into consideration for BEV tires.
Dustin Lancy, commercial product marketing
manager at Goodyear, says BEV manufacturers'
tire performance objectives often center on tire
rolling resistance and steer axle tire load capacity.
"New technologies for EVs focus on rolling
resistance supporting extending the range of the
vehicles," says David Pressley, customer engineering support manager at Michelin North America.
"Also, load carrying capacity is important with
EVs. Range is important to EV manufacturers and
sometimes additional batteries are needed. The
size and location of the batteries can increase the
load on tires."
While not all tire manufacturers have current
offerings specific to BEVs, many have such products in development, meaning there should be a
variety for fleets to choose from by the time BEVs
become more readily available.
For now, fleets who are early adopters of the
first BEVs would do well to spec tires with low
rolling resistance to maximize miles per charge,

and proper load capacity ratings to support the
extra weight of the batteries.
Rabe suggests that fleets operating BEVs now or
expecting to in the future should consider partnering with a tire manufacturer who has already
developed expertise with BEV tires.

BEV tire maintenance

Tire maintenance is one aspect that does not
change much from ICE vehicles to BEVs. Proper
inflation and alignment are of utmost importance
in both applications.

says. "Maintaining proper tire pressure improves
tire runout, minimizes irregular wear, reduces fuel
consumption, and improves safety. It also delivers
20 percent longer casing life for retreading versus
a tire that is just 10 percent underinflated."
A large part of maintaining proper tire pressure
comes down to ensuring drivers are completing
pre-trip inspections, Michelin's Pressley reminds.
Tire pressure must be checked properly, too.
Thumping a tire to check its air pressure will only
identify when a tire is completely flat, Rabe adds. It
will not detect the 10 to 20 percent underinflation
that can impact tire performance.

"Without proper inflation and alignment, you can
imagine the intended tire contact with the road
is not being fully realized, which will impact its
ability to deliver on its full traction, wear, and
range potential in an EV drivetrain application."
Mitch Kritzell, director of commercial tire development, Bridgestone
Americas Tire Operations (BATO), U.S. and Canada

»Continental's concept tire, Conti
e.MotionPro, which was developed
for the MAN CitE electric truck.
Image courtesy of Continental

"Ensuring proper inflation maintenance and tire
alignment are key to ensuring the potential of the
tire and vehicle can be realized," says Bridgestone's
Kritzell. "Without proper inflation and alignment,
you can imagine the intended tire contact with the
road is not being fully realized, which will impact
its ability to deliver on its full traction, wear, and
range potential in an EV drivetrain application."
Continental's Rabe agrees, adding that proper
tire inflation also improves vehicle safety as well
as tire casing life for retreading.
"Maintaining proper tire pressure ... is the best
way to extend tire life and increase retreadability, as
well as maintain intended rolling resistance," Rabe

Tire monitoring and inflation technologies can
streamline this task and help fleets ensure tires
are at their proper inflation. TPMS sensors such
as Continental's ContiConnect Yard connect to
receivers any time a vehicle enters the yard and
alerts maintenance personnel if a tire is detected
outside the set air pressure threshold.
This solution and others like it are designed to
help fleets maintain proper tire health, allowing
them to maximize the efficiency with which each
vehicle operates and extending the tread life of
each tire as much as possible. These considerations are especially important when it comes to
BEVs, since return on investment will rely at least
partially on tire longevity and maximizing the
number of miles driven per charge.
For related content, visit:
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October 2020 | VehicleServicePros.com

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Fleet Maintenance

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