Contents
Consider
these recent changes in automotive tire service:
High performance vehicles now use 17, 18, 19 and 20
inch wheels from the factory. OEM's are using taller
rims and lower profile tires to improve handling
and road feel. Dealers sell “Plus One” through
“Plus Three” fitments to average consumers for
their inexpensive vehicles. Performance rims range
from $300.00 to as high as $1,500.00 each. Speed
rated tires range from $150.00 to $600.00 each.
In this day and age, it's possible to service a
vehicle with over $9,000.00 worth of wheels!
Result: If improperly
serviced, one set of damaged wheels can cost over a
thousand dollars. Untrained employees, improper procedures
and the wrong equipment become the instant ticket
to a service disaster. Damage to the inside of
the rim, from traditional tire changer “steel jaws”
is noticeable and unacceptable to the consumer.
Higher horsepower and ABS brake
systems are the trend. Improved acceleration
and braking require the design of a tire with
a tighter bead to prevent slippage on the rim. Tighter
beads help prevent recurring balance complaints.
Result: When improperly serviced, tighter beads tear. This creates
potential liability problems during inflation or with
the vehicle after the service is completed.
The manufacturer places extreme importance on customer
satisfaction. Luxury performance cars and sport utility
vehicles now may use specially designed rims to “lock
the bead to the rim.” These designs prevent
tire–to–rim slippage caused
by hard acceleration, severe braking or low
air pressure, eliminating vibration complaints.
Bead locks also prevent instant loss of air when
a rim is bent at high speed, potentially saving lives.
Result: Bead lock type rims make it
extremely tough to break the bead with a side mounted
shovel. Damage to the inside and outside of
rim and tire during bead breaking is almost certain.
Some shops resort to sawing the tire off the rim in
order to replace the tire!
On bead lock “AH2” design
rims, beads should be broken by rolling the
bead off the rim, preventing damage to the rim and
sidewalls of the tire. This is not possible with
traditional shovel type systems that violently
“break the bead.”
Run–flat tires will be standard, on some 1997 models, eliminating
the spare and effectively increasing trunk storage
space. Sidewalls are four to six times thicker than
conventional sidewall tires.
Result: Bead breaking and lubricating
the tire before removal is time consuming. Demounting
and mounting are extremely laborious. Seating the
bead may take upwards of 60–80 psi! Use of an
inflation cage is mandatory. Detailed professional
procedures for service and diagnosis are also
mandatory.
Today's performance applications are incredibly
tough to service without potentially inflicting
severe damage to the tire, rim and/or operator. Intensive
re–training and a close review of tire changing
equipment are forcing this segment of the automotive
industry to demand PROFESSIONALISM.
Drawbacks
Of Conventional Center Post Tire Changers:
The center post tire changer was designed years
ago for servicing of steel rims. It secures the rim
by use of a center cone through the pilot hole.
With the advent of larger wheels, lighter materials
and lower aspect ratio tires, greater stress
is placed at the center of the wheel during bead
breaking. As a result, the wheel is susceptible
to bending during the bead breaking process.
Tools available with this type of equipment
are inadequate when servicing the new tough wheel combinations.
Multiple operators must gang up and force the
tire onto the rim with pry bars. Shop “remedies”
are created to overcome the ineffective performance
of the equipment. These attempts are dangerous
to wheel and operator and increase the risks
of liability.
Drawbacks
Of Traditional Table Top “Steel Jaw” Tire Changers:
Traditional “steel jaw” clamp, table type tire
changers were designed in Europe many years ago
to service steel wheels and easier alloy rim and
tire combinations.
When steel jaw table–top
designs are employed, many factors add up to
create problems when servicing the new tough tire and
rim combinations.
- In order to clamp the wheel internally,
steel jaws must embed into the rim. Custom
rims are visually damaged. Anti–corrosion coatings
are destroyed, voiding warranties. Jaw points
eventually wear and do not grip effectively.
The solution may be to always clamp externally;
however very few operators spend the time and extra
effort. Inflating the tire in this manner
is dangerous. If properly removed and then reclamped
internally, the process becomes cumbersome.
Slippage scoring at the rim flange area is common during mounting
and demounting tough of wheel combinations.
- Clamping tables with jaws usually are split
between air-driven cylinders and “slave” linkage
or rod–driven devices. Over time they produce
uneven clamping force and further increase
scoring damage.
- During busy shop periods, air pressure
can drop below acceptable levels, further complicating
the clamping problems associated with air
cylinders, worn linkage and flattened steel
jaw points. There is a good chance the rim
will not remain secure and will score as it
spins. Steel mounting heads, when adjusted
too far from the rim, may slice into the rim
if it moves off center.
- Clamping always takes place at the bottom
of the rim. The design forces the operator
to work at difficult positions when handling
wide, deep wheels. In addition, the table
may serve as a launching pad if the wheel/tire
combination fails during pressurization.
- Fixed–position steel mount/demount heads
used on traditional European changers require
the operator to increase the gap from bead to
wheel to avoid damaging the wheel. Normally,
the operator is encouraged to move the steel head
farther away from the expensive rim. The lower
the aspect ratio of a tire, the greater
the risk of bead tearing damage.
Drawbacks
Of Shovel–Type Bead Breakers:
This type of bead breaker was not designed for low–profile
tires and the “rim protection” tire designs of today.
Many low–profile tires are designed so the sidewalls
protrude out from the flange of the rim to protect
the rim from curb damage. If the operator places
the shovel close to the rim flange, it may slip
off the high protection portion of the tire and
slam into the rim. If the operator chooses to
place the shovel closer to the tread area, it
can cause the tire to be severely deformed in
the sidewall area. The enclosed UNIROYAL publication
points out the dangers of demounting high performance
tires on low performance designed tire changers.
It is clear: any tire changer with a side
mounted shovel for bead breaking is a potential
liability when used on today's high performance wheels.
The Technology Driven Solution:
The Hunter TC350 is the next generation of
tire changers, responding to the latest advances
in wheel technology. The TC350 is an intelligent
design with three major features acting in unison
to deliver the ultimate in service. Forces of
the bead roller work in unison with the clamping
system and articulating arm. The TC350 is the
tire changer which all other future designs will
try to emulate.
TULIP
DESIGN CLAMPING SYSTEM
An exclusive “tulip”
clamping system with rubber protected pads allows
the wheel to shift during service without damage
to the wheel. Wheels of 5” to 23” and up to 19”
wide can be clamped. Centered by the hub on a spring
loaded device, even the widest rims can be serviced
at the same work height as narrow rims.
Articulating
Arm With DuPont Zytel Mount Head
The unique design of the three point articulating
arm accommodates an extreme variety of wheel diameters
and widths. Because there is no swing arm obstruction
or need for locking and positioning of the head
away from the wheel, productivity is increased. As a result,
the tire bead undergoes significantly less mounting
stress, and the rubber pad clamping system performs
regardless of whether the wheel is clamped straight
or crooked. The arm follows the rim as it rotates.
If the tire is mounted or demounted improperly,
the mount head will break, saving the tire and rim
from damage. Designed as a wearing component,
the mount head is inexpensive and simple to replace.
Bead Roller Assembly
Two–finger activated air over hydraulic bead
rollers allow the operator to safely and quickly
loosen the bead where it is seated on the rim.
The design allows complete control as the rollers
quickly are positioned to the rim edge by air
cylinders. The rollers move under the flange
of the rim with a unique cam action. The hydraulic
force of up to 4000 lbs. per roller is placed at
the strongest area of the tire for bead loosening,
the bead itself.
The Bead Roller Assembly assists all phases of
tire service:
- Bead Breaking
- Demounting
- Mounting
- Tire and Rim Matching
- Inflation
Form 3967T, 1-96 |
