“The latest hub and wheel end technologies for steer, drive and trailer axles offer fleets complexity reductions, maintainability increases, and overall total cost of ownership savings,” says Steve Slesinski, director of global product planning for Dana. “Fleets should look to industry-proven systems to increase reliability and reduce downtime.”
Leslie Kern, product development manager, heavy duty, at SKF USA Inc., which also markets CR wheel seal products, describes the three main types of wheel ends available today. Included are Unitized, a non-serviceable, greased design; PreSet, a serviceable unit with pre-adjusted bearings; and manually-adjusted bearing hub assemblies.
“Fleets should consider the cost of ownership versus cost of operation when making hub choices,” Kern says. “The cost per wheel end may be higher for Unitized or PreSet configurations, but Unitized hubs only require regular inspection, as all types of hubs do. Fleets can expect extended service life with a factory assembled and sealed hub assembly.
“The least expensive hub type in terms of acquisition cost is a manually adjusted hub,” Kern continues. “This may be a good choice based on the length of time the vehicle will be owned, but the cost of operation can go up due to shorter service intervals. In addition, a wheel end that has been serviced adds more variables into life expectancy because variances in end play can shorten optimum wheel end life.”
PreSet hub assemblies typically provide good service life and can usually be refurbished to OEM condition. “The old design, used in the commercial vehicle market prior to 2000 with inner and outer bearings with oil bath seals, has largely been replaced by PreSet hub assemblies,” says Ron Carroll, product manager of wheel end and driveline vehicle component solutions at Federal Mogul, provider of National wheel end products. “These hubs come from the manufacturer with ‘preset’ preload and end play, which makes installation exceptionally easy.
“The most popular use of these hubs is on drive and steer axles for Class 6, 7 and 8 trucks,” Carroll explains further. “The precision and tight tolerances of these assemblies significantly increase bearing and seal life, and the bearings within these hubs are replaceable.”
Recently, ConMet rolled out its PreSet Plus hub, which incorporates an integrated spindle nut to simplify installation and aid in removal of the assembly if service is required. “PreSet Plus provides OEMs with a product that is even easier to install and makes it a whole lot easier for technicians to service,” explains Mark Wagner, vice president of wheel ends for ConMet. “While PreSet took the task of bearing adjustment out of the hands of the technician, PreSet Plus provides a self-piloting assembly that only requires the integrated nut to be torqued and a retaining snap ring to be engaged.”
OEM and aftermarket long life wheel end packages utilizing premium components are becoming the norm in the trucking industry, says Charles “Chip” Stuhr, director of marketing at Stemco. “More than 80% of trailer manufacturers we work with use these wheel end systems. We also are now seeing more integrated solutions that include brake linings and drums as part of these long life packages.”
Tom Hewer, vice president of development engineering at Webb Wheel Products, points out that when fleets specify wheel ends, including brake drums, they also should consider new stopping distance regulations. “To meet the new standards with drum brakes, which is still the choice of many fleets, there has been some increases in brake size,” he says. “Fleets need to be sure they are spec’ing these wheel end systems correctly, especially for replacement parts. For example, larger brakes require different drums.”
Most fleets are trying to simplify wheel end specs, notes Mark Stangl, manager of the product management team, commercial vehicles aftermarket at Timken Co. “From a fleet manager’s perspective,” he says, “a common wheel end design using standard equipment for drive and steer axles makes sense for maintenance and for meeting parts needs.”
In service, notes Dan Humphrey, regional manager, commercial vehicle aftermarket at Timken, a challenge technicians face is identification of the style or type of wheel end they’re servicing. Fleet managers, he adds, should work with suppliers to ensure that proper training on identification and service procedures takes place. The availability of replacement parts is an important consideration, as well.
The most common failure mode for most bearings is a lack of or improper lubrication, says Scott Jenkinson, engineering manager, hydraulic brakes and wheel ends at Meritor. “The oil seal keeps the correct amount of lubrication in and harmful contaminants out,” he says. “Regularly checking and replacing the oil seal is critical to a successful preventive maintenance program.“
Jenkinson goes on to explain that a leading cause of premature wheel seal failure is damage to the seal during installation. Common errors include not lubricating the seal properly during installation; not fitting the seal in the hub squarely; not torquing the bearings up correctly, or using an incorrect lubricant for the application.
electing the best wheel end systems based on manufacturer’s recommendations and past experience is the first step toward ensuring long component life. Following up with a comprehensive and effective maintenance program for wheels ends further ensures trouble free operation and lower operating costs.
Bee Line Co.
LC7500 Laser Guided Computer Wheel Alignment System
The all-new LC7500 computer alignment system incorporates a 32-in. HD TV monitor. The system’s software screens have been redesigned to maximize font size for ease of viewing and drop-down menus make it easier to navigate. Fewer moving parts in the laser assembly eliminate loss of accuracy and the need for repair. The system also features target board sensors and processors that operate at 88MHZ vs. 4.5 MHz in past systems, along with a hardware driven design that allows for quick calculations and precise laser positioning. The unit’s Laser Line Generator has 200 sensors per inch.
Greg Smith Equipment
Atlas Edge 801 BlueTooth Heavy Duty Truck Alignment System
Customized for all truck axle configurations, the Atlas 801 truck alignment system features BlueTooth wireless data transmission and the FastClamp system that fastens to the wheel by gripping the tire. Only four color-coded buttons operate the Atlas 801, and each sensor head has the four-button control panel so the system can be operated from the closest sensor. To update software and diagnose issues, the Internet-based TeamViewer allows an alignment system service technician to take control of the Atlas 801 and correct issues remotely.
Hunter’s heavy-duty alignment system incorporates WinAlign HD alignment software to deliver procedures and instructions to technicians on over 60 heavy-duty axle configurations. The software also includes an extensive database of specifications supplied by heavy-duty vehicle manufacturers. WinAlign HD automatically calculates and displays all alignment measurements in a color-coded format to show angles that are out of specification. New DSP506T heavy-duty wheel sensors from Hunter provide instantaneous data transfer with the alignment system. Optional cordless models use XF-Radio technology to provide high-speed communication without cables connecting the sensors to the console. The optional ShopResults.net Internet-based feature of the Hunter system communicates alignment results to fleet managers, stores alignment records, and produces management reports. ShopResults.net works off a secure web server.
Truck & Trailer Alignment Aids
The Truck Toe Alignment Check Set is a scribe-type toe gauge for trucks and other large vehicles. The one-person pointer and scribe is designed to read toe by measuring the distance between marks previously scribed at the approximate center of the tire treads. The pointers are adjustable to hub height for greater accuracy. The Truck Front Slip Plate Set for use with the scribe-type toe gauge has steel slip plates that allow unrestricted movement of the front wheels. The Tandem Axle Spacing Caliper checks the space between the axles of tractors or trailers, ensuring correct alignment and tracking. Myers also offers a Trailer Alignment Measuring System using kingpin and universal axle extensions to provide a fast, accurate method of checking trailer axle alignment without removing the wheels. Axle extensions extend the axles beyond the wheel rim and tire so measurements can be made from the king pin center.
|For More Information:
Federal Mogul www.federalmogul.com