For petroleum carrier Harris Transportation, specifying the right components is a critical element of success.

HARRIS TRANSPORTATION TRUCK SPECIFICATIONS:

Model: Freightliner Century Class

Wheelbase: 246 in.

Engine: Mercedes Benz MB 4000; rated 450 hp, 1,550 lb/ft torque

Transmission: Eaton Fuller UltraShift

Driveshafts: ArvinMeritor

Front Axle & Suspension: Hendrickson AIRTEK

Power Steering: TRW

Rear Axles: ArvinMeritor

Tag Axle: Hendrickson; liftable and steerable

Brakes: ArvinMeritor Q Plus

ABS: Meritor WABCO

Automatic Slack Adjusters: ArvinMeritor

Parking Brakes: MGM Long Stroke

Wheels: Alcoa, aluminum

Tires: Michelin X One; 445/50R22.5, XDA drive

Air Compressor: Meritor WABCO

Air Dryer: Meritor WABCO

Air Cleaners: Donaldson

Fan Clutch: Horton

Seats: National

Fuel Tank: 100 gal.

Product Pumps: Blackmere

With a gross weight of 105,500 lbs., the 95 truck and trailer combinations on the road for Harris Transportation Co. operate around the clock, serving major oil companies, wholesale and retail distributors and several large grocery-store chains in Oregon, Washington, Idaho and Arizona. Headquartered in Portland, Ore., Harris said it is the largest petroleum bulk carrier in the Northwest.

Consisting primarily of Freightliner Century Class trucks, as well as a few Mack models from a recent acquisition, the Harris fleet averages 140,000 miles per year. The oldest Freightliners in the operation are 1998s, and the newest are 2007 models, each designed to last seven or eight years before trade. Trailers are 30-ft. Beall aluminum tankers spec’ed for a 14-year service life.

“Our four-axle trucks each pull a four-axle trailer separated by a 14-ft. drawbar and carry approximately 11,500 gallons of gasoline,” says Bob Moore, fleet manager. “Lightweight specifications are of great importance to our operation. Most of the time, we bill by the gallon, so the lighter our equipment, the more payload each truck and trailer can haul.”

For example, Harris has switched from 14-liter Detroit Diesel Series 60 engines to 12-liter Mercedes Benz MB 4000 powerplants to save weight and is spec’ing Eaton Fuller UltraShift 10- and 13-speed transmissions and eliminating clutch assemblies. Items Moore also lists as saving weight on the Harris fleet include Alcoa aluminum wheels and Michelin wide-base single X One XDA drive and XTE trailer tires, which, he says, save 100 lbs. per wheel end, compared to dual tire and wheel assemblies.

Moore says he specs aluminum hubs and aluminum transmission bell housings to save weight. In addition, he says the Hendrickson AIRTEK integrated front-axle and air-suspension system reduce weight by up to 100 lbs., compared to a standard assembly.

Working with suppliers Harris has been able to identify and evaluate lightweight specifications that also meet its needs for durability, reliability and ride quality, Moore says. One instance in particular where this practice has paid dividends for the fleet is in the new Meritor SimilAir composite trailer springs that are now standard on the fleet. ArvinMeritor’s Commercial Vehicle Systems is the exclusive distributor of Liteflex truck, trailer and specialty vehicle composite mechanical springs.

Harris Transportation has used composite fiberglass mechanical springs on its tank trailers since 1997, mostly because of low weight, simple design and ease of maintenance. “Meritor SimilAir Composite Trailer Springs are lighter in weight, which can help increase our payload capacity,” Moore says. “Tandem suspensions equipped with SimilAir springs weigh as much as 240 lbs. less than the lightest air suspensions and more than 100 lbs. less than mechanical suspensions we’ve seen.”

The bottom-line benefit of the new SimilAir springs for Harris goes beyond weight savings, Moore says.

“Poor ride quality had us contemplating a switch to air suspensions, a heavier, more complex, and expensive alternative that is not typically found on combinations with a drawbar and turntable doll,” he says. “We liked the ride quality of an air suspension, but didn’t feel comfortable that air ride was the best choice for our operation.

“A smooth ride is very important because our trailers start out at 65,000 lbs. fully loaded with fuel and drop all the way down to 12,400 lbs. at the end of their delivery schedule,” Moore says. “They’re empty the whole trip home and running on tires that are inflated to haul that heavy load, so they tend to bounce around. An empty tank trailer gets two good jolts as the axle sets cross each joint in the road surface, especially on the concrete highways of the Pacific Northwest.

The driver can’t always feel it from the cab, but in the mirrors, you can see the forward and rear marker lights on the trailer oscillating as the ends of the trailer teeter up and down.”

The Meritor SimilAir springs deliver a smoother ride because the trailer settles down when it’s empty, according to Moore. “The springs dampen the shocks the trailer receives when it hits seams or cracks in the highway,” he says.

The shock and vibration also can result in tank fatigue, which means that Harris Transportation has to be especially vigilant about preventive maintenance.

“Because each trailer works in combination with a truck, our equipment utilization depends on both units being ready to go any time,” he says. “Repairing aluminum and tank hardware is complicated and expensive and even more so when the work is unplanned.

“Meritor’s SimilAir composite mechanical leaf spring, with a 22,400-lb. rating, delivers the ride close to an air suspension without the added weight, maintenance and cost,” Moore says. “Its fiber-reinforced epoxy material is proving to be more durable than steel and won’t rust or lose strength with age. We were looking for the right blend of weight and durability without having to sacrifice ride quality when we’re running empty, and we found it in this product. We’re spec’ing them on all new trailers because, down the road, this is going to increase service life and lower costs.”

State-of-the-art equipment specifications remain central to Harris Transportation’s ability to provide quick and dependable service to its customers.

“In our customer markets, we’re seen as a leader in dependable, professional service,” Moore says. “As the person in charge of specifying and maintaining the equipment, one of my challenges is to build reliability into the vehicle right from the time it’s specified. With our latest choices, we’re further along in our ongoing desire to achieve that goal.”