Skirts and tails and more: buying your first trailer
Tractors have traditionally been the most glamorous and efficient equipment on the road while the nondescript trailer packs the load. With skirts, tails and other enhancements making the scene, that's changing. If you are thinking about buying your first long-haul trailer in 2014, it's time to make a more comprehensive plan and buy one that will take you into the future.

By Paul Abelson, senior technical editor

Trailers are a big part of the combination that puts the money in your pocket. If you have your own, more money goes to you. If 2014 is the year you go trailer shopping, there are five things to keep foremost in your plan.

They can be categorized according to function: aerodynamics and fuel economy, maintenance, structure and components, control and protection. Other functions are important, like cargo handling, but that’s going to depend on weight and preference. The top five considerations are in no particular order of importance and will be dictated by your operation.

Aerodynamics
Aerodynamic design is recognized as a leading contribution to improved fuel economy. According to the Environmental Protection Agency’s latest emissions regulations, they will help your bottom line at speeds over 50 mph.

The effectiveness of aerodynamics increases with the speed of and the drag on a vehicle. For example, when a truck increases from 60 to 70 mph, that is a 17 percent increase in the truck’s speed. However, drag increases 36 percent between 60 and 70 mph.

Drag increases energy needed to drive down the road, energy that comes from your fuel. Reduce the effects of drag by using aerodynamic devices and improve fuel mileage.

Drag-reducing devices minimize the interruption to air flow over, around and under the vehicle. Research now shows that even behind an aerodynamic tractor, the trailer generates as much as 65 percent of the vehicle’s total drag. As a rule of thumb, every 3 percent reduction in drag can improve mpg 1 to 1.5 percent depending on speeds.

Under test conditions, SmartWay-approved trailer skirts can improve fuel mileage by 5 percent or more, but real world conditions vary. When tested, skirts are properly matched to rear tandems so they keep air flowing smoothly from skirt to wheels. With sliders in use and tandems in the full rear position, the gap between the skirt and wheels can be almost enough to render the skirt useless. Unlike skirts, the trailer tails from ATDynamics are effective in all conditions and consistently do what they are supposed to do. They are popular with a number of fleets, and more and more we see them on the owner-operator rigs.

Under-trailer devices smooth air flow at the axles and suspension, but they are not as prevalent as skirts. Trailer nose shields are effective in smoothing air flow, even behind tractors with air deflectors. They work best in cross winds, and are worth consideration when operating primarily north-south with our prevailing westerly winds. Even flat disc wheel covers that keep turbulent air out of deeply dished trailer wheels and mud flaps that allow air to flow through have shown short-term payback.

Maintenance
Whatever extends life of trailer components or reduces the need for maintenance provides a definite and measurable payback. Lighting is a prime example. Past studies of the Technology & Maintenance Council showed lighting and wiring were the highest cost items of all truck maintenance. Today, operators using sealed wiring harnesses, sealed connectors and nose boxes and LED lamps in place of discrete wiring and incandescent bulbs report virtually no lighting and wiring problems. 

While steel components corrode easily and destructively, aluminum’s white corrosion forms a protective oxide barrier if not abraded away. Consider aluminum components as maintenance items as well as for weight savings, but be careful not to mount aluminum in direct contact with steel body parts. Consult with your trailer supplier before mounting aluminum to steel or vice-versa. Stainless steel, however, can withstand contact in most salt and brine environments.

Structure and components
Unless you’re already hauling low-density, high-cube freight, consider weight. If you always “cube out,” weight saved means better fuel economy. There is often a cost penalty for lighter components. One example is an aluminum wheel, which may cost more than twice what a steel wheel does. When money gets tight, you need to consider costs and benefits from weight savings.

Tire maintenance is crucial to economical operations. Trailer tires are often overlooked. Meritor’s Tire Inflation System from PSI’s benefits apply to single truck operators. Limping home with a flat destroys the flat tire casing and severely overloads the good tire making it unserviceable, too. And with pressure down 10 percent or more, fuel economy can fall by 2 to 3 percent.

Control and protection
What about a trailer stability system? Should you invest? My opinion is yes, if you have the funds. I suggest a trailer stability system from Bendix or MeritorWABCO. I’ve seen experiments with trailer rollovers and real-world rollover footage and I’ve participated in some test drives. Once a trailer starts to roll, it will snap the tractor on its side before the driver can even sense the loss of control.

You may not be able to afford everything on your wish list, so prioritize. Consult with people who operate in your particular niche of trucking, even hauling general freight. Other equipment owners are your best source of information on how to prioritize your investment. Your dealer may be a good consultant, but he may want to sell what’s in stock.

Decide on your top items – those that you absolutely must have, and those that will pay a good return on your investment but may not be in the “absolute necessity” category. Keep going down the line.

It’s a big decision. Use these five basics to make your list. Now, let’s go trailer shopping. LL