Overdrive Magazine | Trucking Business News & Owner Operator Info
Issue link: http://read.dmtmag.com/i/409537
November 2014 | Overdrive | 27 1 ROOF FAIRINGS It's fair to say that the tractor-trailer aero- dynamic revolution began decades ago with roof fair- ings. Long before fuel econ- omy became a priority, it was obvious that having air smack headlong into a tall, fl at trailer nose was extreme- ly ineffi cient. In 1976, automotive engineer Donald Herpel founded Airodyne, which introduced one of the fi rst three-dimensional roof fairings. With cheap diesel fuel the order of the day, Ai- rodyne struggled to interest fl eets – until the OPEC oil embargo later in the decade forced carriers to look for new ways to save fuel. Today, manufacturers offer integrated roof fairings as standard equipment be- cause they are so effective. Airodyne, which still works with truck makers, says that full three-dimensional fairings with closed sides and tops that extend at least to the truck cab's rear can deliver up to a 15 percent fuel savings and pay for themselves in three months. Airodyne says that a full roof fairing delivering just a 10 percent increase in fuel economy can save $6,900 a year in fuel. Even more basic fl at-style roof fairings, typically found on daycabs, can deliver up to 5 percent in fuel savings. 2 LOW-ROLLING- RESISTANCE TIRES A deep tread tire will have more rolling resistance when it is new because there is more squirm in the tread. The engine requires more power to overcome that resistance. Low-rolling-resistance tires use advanced com- pounding materials to construct tires with more durable tread but at shal- lower depths. The durability from the advanced materials gives the tire a service life comparable to tires made from more traditional com- pounds. These tires can contrib- ute as much as 20 percent toward a vehicle's fuel con- sumption performance. A truck can use as much as $70,000 worth of diesel a year, which translates to about 20,500 gallons. By switching to low-rolling-re- sistance tires, starting with the trailer axles and continu- ing with steers and drives, you could save as much as $2,100 per year in fuel costs. 3 ALUMINUM WHEELS It's all about weight when it comes to wheels and fuel effi ciency. At about $350 a unit, aluminum wheels can cost up to three times more that those made of steel. But most long-haul fl eets looking to take all possible weight out of a tractor are willing to pay that premium, says Robert Flynn, director of product marketing for the Accuride wheel, made by market leader Alcoa. Alcoa's most drastic weight savings package with aluminum wheels is a 14-inch wide-based tire confi guration. The total weight savings on the axles and wheels is 1,400 pounds. That translates to a fuel sav- ings and, depending upon freight, extra revenue. Also, resale value for aluminum wheels results in a 75 percent return on the original investment up to 10 years later, which is far more than steel wheels, Flynn says. There also are mainte- nance savings since alumi- num wheels do not have to be checked for rust and have it removed. Alcoa says that some cus- tomers have seen a return on investment for aluminum wheels in a year or less. 4 TRAILER SIDE SKIRTS Trailer side skirt manufacturers say these devices can boost fuel econ- omy by more than 5 percent and cost about $2,900 per trailer to install. Trailer side skirts were the fi rst serious attempt to streamline air moving under a dry van. They have gone from curiosity to common- place in a short time. While early aerodynamic efforts targeted the tractor itself, streamlining what is essentially a long, rectangu- lar box proved to be more problematic. While early side skirts suffered from durability issues, the latest generation is engineered to achieve greater ground clearance to help reduce impact damage. Utility Trailer recently in- troduced a proprietary line of dry van skirts that fea- ture a galvanized high-ten- sile steel bracing system designed to allow inward and outward flexing, and to be bent back if damaged. The skirt also is man- ufactured with a UV-pro- tected bidirectional fiber- glass-reinforced plastic construction. Its forward edge is bolted securely with a spring attachment at the support leg assembly. Manufacturers now design highway tractors with roof fairings as stan- dard equipment. Low-rolling-resistance tires such as Bridgestone's Ecopia are made with durable shallow tread. While aluminum wheels cost more than steel, payback can be quick. Side skirts have become much more common because of their aerody- namic efficiency.