Proper vehicle alignment is a major area of concern because of its direct implications on the life of tires, fuel economy and safety. Alignment is often thought of in connection with a truck’s steer axles only. However, the rear axles on a tractor also must be properly aligned, and tractor and trailer units need to be aligned with each other (in combination vehicles) for optimal performance.
Fleet experience and industry research shows that misalignment can cause a variety of problems, including:
Irregular tire wear
Misalignment causes tires to scrub and oppose each other. What’s more, excessive and/or uneven tire wear can reduce control of steering inputs, particularly on low-friction surfaces like wet pavement, which compromises the vehicle operator’s ability to execute quick, precise maneuvers.
Misalignment between front and rear axles on a tractor, and/or between the tractor and trailer units themselves, creates dog-tracking going down the road. This causes the engine to work harder because rolling resistance is increased, and fuel economy suffers.
Dog-tracking is a condition where the rear end is offset from the front. In the case of a tractor trailer, the trailer is offset from the tractor.
Misalignment conditions can also often lead to higher-than-normal vibration levels in the steering wheel and/or the operator’s seat. The result can be an uncomfortable ride that contributes to driver discomfort, muscular fatigue and stress.
Trailer misalignment will also cause increased tire wear, greater aerodynamic drag, reduced stability and diminished fuel economy.
Essentially, trailer alignment involves adjusting trailer components to line up according to three parameters – axle orientation, axle toe and axle camber – so that the trailer tracks straight and true.
COSTS ADD UP
Regardless of the type of vehicle, one that is poorly aligned can reduce the driver’s level of control, which then adversely affects vehicle stability and has negative consequences for operating costs, says John Messina president-elect of Truck frame and Axle Repair Association (TARA) and president of Tampa Spring Company.
TARA is the premier group in North America whose focus is on quality frame and axle repair and maintenance of trucks, trailers, RVs and heavy equipment vehicles. www.taraassociation.com.
Founded in 1927, Tampa Spring Company is family owned and operated with four shops in Central Florida specializing in suspension overhauls for trucks and trailers; frame repair, straightening and modifications; complete wheel alignments; and many other shop services. www.tampaspringco.com.
“In this day of $4 per gallon diesel fuel, pulling a loaded trailer that is not in alignment with the tractor will increase the cost of operation per mile by cutting fuel economy,” Messina says. “The truck engine will have to run at a higher rpm to compensate for the extra drag of the trailer.
“Tires will prematurely wear and have to be replaced more often. The price of tires has been increasing along with the price of petroleum, as this is the major component in the manufacture of tires.”
When you need to lift a trailer that is detached from the tractor, the logistics and safety requirements can be challenging, even for the most experienced fleet operator or service technician.
The majority of trailers are serviced and inspected outside. Further, in contrast to the more straightforward requirement of lifting a full rig - which can be accomplished with a range of options, including mobile column lifts, axle engaging scissor lifts, platform lifts or in-ground piston lifts, lifting a trailer on its own presents a number of unique structural demands.
“The goal is to pick up and support the chassis of the trailer in the same manner as it is normally supported when on the road and supported by the fifth wheel,” explains Peter Bowers, technical sales support manager for Stertil-Koni, the global market leader in heavy duty truck lifts and bus lifts. www.stertil-koni.com. “At issue is how best to support the trailer frame, which supports the trailer when it is not hooked to the tractor.”