According to Bruce Stockton, vice president, maintenance and asset management for Con-way Truckload, “The real reason we began looking at lighter weight components was to increase fuel efficiency. Prior to October 2002 [pre-introduction of the 2002 EPA emission regulated engines] we began discussion about the fact that trucks we spec’d for the future with the new engines were going to be gaining weight due to hardware being added to meet regulations. Since we are paid by the mile and not by weight, we were concerned about the added pounds. Then the ’07 and ’10 engines were introduced and with each of those engines another 1,000 lbs. (500 lbs. per addition) was added to the weight of the truck and we want to have 46,500 lbs. payload capacity for our customers. So we continued looks at ways to cut weight.”
Testing singles
Stockton says, “We began testing Michelin wide-base single tires in 2003, found them to be fuel efficient and started to retrofit the fleet with those tires. From 2004 on we’ve seen improved fuel performance on the vehicles with the wide-base singles. All of our tractors—and by the end of this year, 75% of our trailers—will be equipped with the wide-base singles and we will have 100% of the trailers using the tires by the end of 2011.”
When Con-way started changing from duals to wide-based singles, the company got the driver reaction one might expect—skepticism. Stockton says that at first the drivers either really loved them or hated them. Those that loved them were also the drivers that got the first initial training, he notes, or they were drivers that thought they looked really cool. As more and more drivers are educated about the tires, the general acceptance is greater. The fleet uses training videos developed by Michelin North America.
“One of the questions we ask drivers during training is ‘which do you think is the most important tire on the truck?’ They usually responded ‘the steer tire.’ We would then remind them that the steer tire is a single tire—and they get the point.”
Obviously, Stockton says, the biggest disadvantage to wide-based singles is that if a tire blows out, the truck is out of service and the driver can’t “limp home.” But, he notes, with the soon-to-be-enforced CSA 2010, loosing one of the duals is also an out-of-service incident and the driver will be in violation if he or she attempts to “limp in.”
Loosing pounds
In addition to “loosing” weight by going from duals to wide-based singles, the fleet took weight off the vehicles by taking out unneeded components. Stockton said he worked with his dealer principal, technicians and drivers, asking them to look over a typical truck, which he had parked in the shop, and tell him which components they thought might be eliminated to save weight. One driver told him he never put more than 100 gal. of fuel in during a fill and, since the truck had two 100-gal. tanks, spec’ing just one could save weight. The fleet talked with other drivers and checked fuel records. The average fill was 80 gal., so it was determined that fuel capacity could be reduced. The weight savings came from 40 gal. less fuel onboard.
Other components that were eliminated included: rear steps on the deck plate (all the fleet’s tractor/trailer connections can be made by a person standing on the ground); a quarter fender (primarily used to protect during bobtail runs; they discovered there were not enough bobtail trips to warrant its use); and an extra bunk (the fleet now specs only for team driver trucks and has put lightweight storage units in that space in the bunk for other drivers).
The fleet is very serious about reducing fuel costs and about having input from drivers on how best to accomplish this goal. Stockton notes that the fleet discussed ways to cut fuel costs and suggested to drivers that they would like to reduce highway speeds from 70 MPH to 65 MPH. While the drivers agreed that they do not need to go 70 all the time, they did want the option for the acceleration. Also, the drivers didn’t want the speed change to affect their delivery times and miles as they related to their paychecks. The fleet agreed to pay them the extra $.01 per mile increase to compensate for the change. The fleet still saved more by increasing fuel efficiency.
Less expense to operate
Stockton says that wide-base singles are less expensive to run that duals. “First of all, there is the lower cost of inventory and labor,” he notes. With fewer tires and wheels on the truck, there are fewer tires in stock and it takes less time to service them. “By 2011 there will be no 18-wheelers in our operation, we’ll have 10-wheelers—and increased efficiency.”
The other piece of the maintenance advantage is that drivers can tell when a tire is low. “While we encourage drivers to use tire gauges to check tire air pressure, they can also just tell by looking when a tire appears to be low. Without the support of a dual next to it, a low tire is obvious. So, we are finding that we have fewer tire failures and less down time.”
The fleet has lowered its tire and fuel costs using the wide-based single tires and has not needed to modify its maintenance programs to accommodate the change.
Tracking progress
Con-way is using Qualcomm OmniVision to track vehicles in real-time. “We have access to the actual miles of the tires. When they are pulled we log the data. Our new Michelin wide-single tires have a 24/32nd tread depth. We run them at 20/32nds and get an average of 263,000 miles per tire. We used to have an average of 260,000 miles per tire, so we’ve improved the mileage.
“To track fuel miles, we use Qualcomm’s onboard diagnostics to monitor idling time and track the fuel numbers using ComData figures. We look at a 90-day MPG average and paid dispatch miles loaded and unloaded.” The only way to measure success is to track your results.
Aluminum wheel advantages
Aluminum usage in vehicle component manufacturing reduces weight, enhancing fuel economy and performance. Every 100 lbs. of vehicle weight savings generates an increase of 1.5% to 2% in fuel economy (MPG), according to Alcoa.
Additional benefits are achieved when targeting weight savings on particular areas on the truck. Weight plays an especially critical role in efficiency when it comes to the drive line of the vehicle. Rotational mass moment of inertia, better known as the effort required to rotate the wheels from power generated from the engine, affects fuel economy in an exponential way. Reducing unsprung weight (weight found in or near the axle and required to be turned by the engine) and improving the rotational mass moment of inertia generates a multiple savings effect over just reducing sprung weight (weight found on the rest of the vehicle).
Replacing 10 steel wheels with 10 Alcoa forged aluminum wheels (weighing 45 lbs. each) results in an average savings of 50 gallons of fuel and reduction of 0.5 metric tons of CO2 per year on a Class 8 truck. Further efficiency gains are made from selecting wide-base wheels. Switching from steel single 22.5-in.x8.25-in. wheels to Alcoa 14-in. wide-base wheels saves 1,429 lbs. on an 18-wheeler. In addition, wide-base tires (mounted to the wide-base wheels) are SmartWay-certified to lower rolling resistance, further increasing fuel economy.
Aluminum wheels also act as a heat sink to run 40 degrees F to 60 degrees F cooler than steel wheels, improving tire and brake component life and further reducing operating costs over the life of the vehicle, according to the company.
Lighter weight aluminum wheels provide increased payload, better handling and improved tire and brake life, all while lowering operating costs. No other component on a truck is as simple to swap out and offers immediate benefits to both the environment and your bottom line, Alcoa said.
TPMS protection
Recently, Doran Manufacturing introduced its Doran 360CE tire pressure monitoring system. The unit is ideal for all sizes and configurations of commercial equipment—including wide singles. Programming and installing the digital LCD display and valve-mounted sensors can be accomplished without any special tools in less than an hour, the company said.
The large-bore sensors are built with high-impact nylon and include potting material to secure the internal components and provide protection against vibration and high temperatures. The components of the system have passed SAE tests by an independent A2LA accredited testing facility to ensure they deliver the longest life and corrosion resistance on the market. In addition, the sensors can also be activated to transmit tire pressure and temperature data with the Doran SmartLink tool during a walk-around inspection, according to the company.
The in-cab display provides real-time monitoring of tire pressures for up to 36 wheel positions, the company said. An indicator light provides “at-a-glance” confidence to the operator that the tires are at the correct pressures and the system is working properly. In addition to the standard Level 1 and Level 2 alarms at 12.5% and 25% below the programmed baseline tire pressure, a unique FastLeak warning is triggered with a drop in tire pressure of 2.8 PSI in less than 12 seconds, along with a high temperature alarm that is activated if a sensor’s temperature reaches 248˚ F. A built-in date/time stamp function records the alarms and a driver lockout function prevents accidental tampering, Doran added.