Building Durability Into Trailers
'Build it so it lasts' is not just a platitude, but good advice for saving money over the long haul.
TOM BERG
EQUIPMENT EDITOR
Spend a few hundred dollars extra right now, when you order a semitrailer, and you will reap many thousands of dollars in maintenance and operating savings over its service life. That should go without saying.
But buyers of van-type trailers -- the most popular, constituting about two-thirds of the vehicles out there — tend to be "price-sensitive," to put it in polite terms.
Vans tend to spend a lot of time sitting in yards, so they don't deserve a lot of investment, the logic goes. They are also being neglected, so mechanical and structural enhancements can keep the vehicle healthy and ready to take a load on the road every time a tractor hitches up to it.
"Durability is a huge part of our business — getting the proper spec for the longest life," says Steve LeClair, senior vice president of marketing for TIP, the giant trailer leasing company with a fleet of 150,000. It buys thousands of trailers per year, based on the demands of customers and the general economy, so it has to know what it's doing.
To achieve durability, TIP "qualifies" a new customer as to needs — what he hauls, the route, loading and unloading practices and other factors, LeClair says. A representative looks at the customer's existing trailers to see if improvements are necessary. Then specifications are set. After trailers are in service a while, the rep confers with the customer to see how the trailers are holding up and what maintenance is required, then makes any needed specs changes.
Aside from special equipment needed by some customers (e.g., a lift gate or ramp), most trailers share certain basics to ensure durability. Bill Pinto, TIP's sourcing manager who specs and orders new trailers, listed them below. He says he considers and sometimes tries new or alternative materials that promise better performance, including some that customers might want.
• Frame rails are 6061-T6 extruded aluminum, one piece, full length.
• Crossmembers are on 12-inch centers (common in the industry), and on 8-inch centers in the rear 4 feet, putting three extra crossmembers where dynamic loading by forklifts is heaviest.
• Flooring is a full (not nominal) 1-3/8-inch hardwood, covered in the last 24 inches (where forklift wheels first bang aboard) by a crash plate with skid-resistant diamond facing.
• Side posts are steel, on 24-inch centers, but on 12-inch centers over the coupler area and king pin. This provides extra structural stiffness in the box structure, especially important in a 53.
• Side walls include 0.050-inch aluminum skin lined with 1/4-inch plywood; full-length, 12-inch-high scuff plate is 16-gauge corrugated steel. Tests with plastic scuff materials have yielded "mixed results," Pinto says.
• Steel posts. Cross section varies by trailer ("We leave it to the manufacturer," he says) and width. Most TIP vans are built with 1-inch-thick walls to get a 100-inch inside width.
• Front wall assembly includes six steel posts (vs. four that are usually standard) lined with 3/4-inch plywood (vs. 1/4- to 1/2-inch standard). A 00-gauge steel bulkhead, welded to the upper coupler's top plate, covers the bottom 12 inches to withstand battering by pallets and forks.
• Roof consists of .040-inch aluminum or .075-inch translucent fiberglass skin over steel bows on 24-inch centers. Pinto says he's looking at new materials that might be more resistant to tears.
• Swing doors feature 3/4-inch A-C plywood core, .025 prepainted white aluminum outer panels, 26-gauge hot-dipped galvanized steel inner panels with Dual Sealer balloon gasket. One locking bar per panel, four hinges per door.
• Rear impact guards are of bolted construction so individual members can be replaced when damaged. RIG designs vary among trailer manufacturers; TIP does not stock pieces at all its locations, but gets them from dealers when needed. The top surface of the horizontal member is slip-resistant, and handles are included on trailers with overhead doors.
• Landing gears have sealed, lubed-for-life, maintenance-free gearboxes. Bracing details include fore-and-aft braces that span six crossmembers instead of the five usually used.
• Running gear. TIP specs axles, hubs and brakes from the same supplier (which it prefers not to name) to get uniformity throughout the fleet. It's also easier to deal with one supplier than two or more.
• Axle hubs are factory sealed with synthetic lubricant, designed either for no maintenance or a minimum interval of 100,000 miles. This design has greatly reduced the need to replace wheel-end seals, LeClair says.
• Brake linings are of extended service spec, 7/8-inch thick vs. 3/4-inch standard. This typically gives 25% more mileage between relinings.
Customers with specific requirements get special attention, Pinto says. For example, heavy inside damage from tough treatment by forklift drivers may require composite-plastic liners or full-height steel-faced plywood. TIP tries to equip the trailer to do a job economically while lasting a long time.
