UHP tires and your service bays:
UHP tires provide the performance and appearance car buyers and car makers want, according to Nick McCullough, president of Rav America, the U.S. division of Ravaglioli SpA of Italy. “Automobile designers continue to specify UHP tires for better handling and speed characteristics. These tire and wheel combinations have a cost effective and positive effect on vehicle styling. Tire manufacturers love competing in the UHP market because it is a profitable market segment as compared to low-cost radials.”
How can dealers prepare for the increasing number of UHP assemblies coming to their shops? MTD asked several manufacturers to find out.
Bosch Automotive Service Solutions: Accessories such as the Bosch 3-Point helper system are essential for changing UHP configurations, according to Scott Farr, wheel service and equipment business development manager for Bosch Automotive Service Solutions LLC. “The Bosch 3-Point helper system is both a wheel and bead saver and reduces the mounting process of UHP assemblies to a one-person operation. A changer without this option drastically limits the range of tires a shop can service without damage. Additionally, UHP tire and wheel combinations are typically much wider and heavier than standard, so highly accurate alignment and balancing equipment are definitely a requirement. Lastly, even with the best equipment money can buy, improper clamping to any of this equipment can cause damage and inaccurate results.”
Hennessy Industries Inc.: Hennessy’s goal is for technicians to not change the process based on the assembly that comes across the tire changer, according to Keefe. “A tire dealer wants to be able to do those UHP fitments on the machine that he does all his other work on. The last two major relaunches of our Coats X-Series tire changers equip our workhouse high-volume tire changers to handle UHP fitments without having to change the process.”
He says the company revamped the X-Series mount/demount head to create a “hybrid duckhead” that handles both UHP fitments and conventional tire and wheel assemblies. Changes to the clamp profile design make it easier to reliably and securely clamp UHP fitments that are difficult to get on the tabletop. The new clamps can be easily added to an existing machine.
Hennessy also improved the bead loosening system. “Based on the amount of UHP fitments that we anticipate those machines seeing over their lifetime, we made drastic upgrades to our bead loosening system to ensure that we maintain the lifespan of our equipment even with these tougher assemblies.”
Cemb USA/BL-Systems Inc.: Mounting helpers are essential for mounting and demounting low profile tires, according to Bob Gibson, special projects manager for Cemb USA/BL, which is the U.S division of Cemb SpA of Italy. “Most standard machines that clamp the rim from the outside are sufficient to change these tires as long as they have mounting helpers. Tire machines that hold the rim down from the center hole usually break the beads in that position and operators have to be careful on stiff bead tires to continue to rotate while freeing the bead and not damage the rims.” Balancing and alignment are critical for high performance and high mileage rated UHP tires, which are most likely mounted on high quality alloy wheels, to reach their expected ratings.
“Wheel balancing machines should be of the type that directly locates the weight and position inside the rim,” says Gibson. “Many of these new alloy wheels do not give you the option of clip-on weights on the outside of the wheel. To properly dynamic balance these wheels, stick-on weights on the inside of the wheel are a must. ”
Hunter Engineering Co.: Fully automatic tire changers enable a technician of any skill level or experience to service a UHP tire, according to Pete Liebetreu, senior product manager. “Hunter’s Revolution fully automatic tire changer uses the same process for all assemblies. The Revolution is a single-process machine and handles typically tricky performance tires such as low profiles and heavy assemblies the same way as the easiest and most basic assemblies. The Revolution’s fully automatic process also protects the rim and tire from damage as all rim contact or near rim contact is plastic.”
If an issue is found during balancing, Liebetreu says Hunter’s Road Force Touch balancer guides the technician through a simple procedure to optimize the assembly. To prevent damage to the outer surface of expensive rims, Liebetreu recommends using a flange plate. He says the Hunter flange plate is universal and can handle 3- to 8-lug vehicles. Low taper collets ensure proper centering. “The Hunter design is dual purpose. The low taper gives optimal centering and the split taper prevents the collet from penetrating too deeply into the hub bore and damaging the wheel or centering on the wrong surface. Centering checks should be performed whenever centering is in question.”
Hunter’s Hawkeye Elite Alignment Systems with patented Quick Grip adaptors attach to the face of the wheel with a scratch-free material and use the tire to apply clamping force. “This takes the pains of rim guard tires and other very tight wheel-to-tire fits out of the equation in the alignment bay,” says Liebetreu.
Ravaglioli SpA: The first step to efficient service of UHP tires and wheels is raising the vehicle quickly and safely, says McCullough. Ravaglioli’s line of double scissors lifts, which are approved by the Automotive Lift Institute, are an alternative to two-post above-ground lifts and in-ground lifts.
McCullough says tire changers differ in key ways from their predecessors. They have larger rim diameter capability which must be supported by a larger and strong chassis. They are powered by 220 volt drive motors which are capable of producing a higher torque rating and delivering variable torque so that the amount of torque is always correct for the job. Inverter controlled 220 volt drive motors enable modern tire changers to offer true variable speed control so that rotation speed can be matched to the task at hand. The power and precision required to break the bead of UHP tires greatly exceed those required by an ordinary radial. “Sidewalls of UHP tires can be extremely slim and stiff, making bead breaking more difficult as well as increasing the risk of rim and tire damage. As a result, the bead breaking devices used by modern tire changing systems must be more powerful and more precisely controlled.”
Modern systems must include auxiliary pneumatic help devices, according to McCullough. Although these components are integrated with the tire changer and assist the operator in many tasks, their most important role is to help keep the bead of the tire in the drop center area of the wheel.
The advancement and proliferation of UHP tires and wheels have added many challenges for the wheel balancing system, too. Larger rim diameters and heavier combinations have increased the difficulty incurred while trying to achieve the precision required by today’s sport suspensions. “The automobile suspension of yesterday was very tolerant of wheel imbalance. Its softer suspension had a tendency to mask imperfections in wheel balancing precision,” says McCullough. “Most UHP wheels are designed to accommodate tape weights so that means that a truly modern wheel balancer must provide special tape weight programs that are both simple to use and result in a precisely accurate job.” He says the Ravaglioli G4.140 is a high end, yet affordable, balancing system using a DC drive system for both accuracy and durability.
“It’s premium grade software is displayed on an LCD monitor and its precisely accurate tape weight program is so easy to use that no keypad interaction is required. The digital eccentricity system accurately measures tire or rim ovality and instructs the operator on ways to improve tire and rim positioning.” ■