Total Vehicle Alignment

Vehicle alignment settings serve a variety of functions in vehicle operation. They affect handling, steerability, stability, performance and safety, among other things. When a vehicle is in total alignment, all wheels “agree” on one direction so there...


“If you think about it, all of the engine horsepower and three-quarters of all the weight carried on the power unit is on the drive wheels,” Beckett says. “Until you get them pushing in the direction you want to go, all you are doing in the front end is trying to overcome that power.” 

What’s more, “aerodynamically, a vehicle going down the road sideways negates all of the aids added to it to slice through the wind efficiently,” observes Josam Products’ Johnson. “A misaligned vehicle is anything but ‘green’ and works counter to the all of the aspects of the creed.”

 

DRIVER ISSUES

Another element to improper vehicle alignment is the impact on drivers.

When a vehicle is not in alignment, the driver is constantly correcting the steering wheel, usually in one direction all the time, Lukavich of TA explains, likening it to a form of Chinese water torture. Drivers eventually get tired and frustrated with constant correction and are less effective and productive.

“Driver fatigue caused by constantly correcting for alignment pulls will become a factor that will impact safety, as well as employee satisfaction,” Hunter Engineering’s says Brock. Misalignment has an impact on driver retention, Johnson adds, because “ill-handling vehicles are a reason for a driver to quickly start looking for another company’s employment.”

 

REGULAR INSPECTION

Good inspection of the tires for early stage irregular wear ought to be a part of any regular preventative maintenance practice, advises Beckett of M.D. Alignment Services. Already in place should be a procedure for reading Driver Vehicle Inspection Reports, looking for any indications of handling issues.

He feels there is no need to measure vehicle alignment on a scheduled PM basis as this “does no more good than dismantling the truck engine to inspect the gaskets. If the gaskets are not leaking they are just fine. By the same token, if the tires are wearing correctly, the alignment is alright. 

“We measure trucks to predict the tire wear,” he maintains. “If you have the tire wear you don’t need to make a prediction.” 

Others feel that measuring and correcting alignment should be performed for all power units and trailers as a part of the PM program, although mileage intervals vary. “This will maintain effective cost per mile expenditures for both fuel and tires,” says Brock.

RAV America’s McCullough says checks at regular intervals are necessary because vehicle suspensions are flexible and, therefore, the alignment will change due to the g-force emitted by the powertrain. Regular alignment checks enable correction of any adverse changes in the vehicle geometry due to wear and tear.

“The choice that the fleet must make is whether to be proactive with a dedicated alignment program or to be reactive and align a vehicle when tire wear takes place and is obvious,” he says. “One method maximizes vehicles tire life and fuel economy; the other does not.”

TravelCenters of America’s Kukavich offers the following example of ROI attainable from a 50,000-mile alignment check for a long-haul rig:

If a rig averages 100,000 miles per year, and the fleet is on a preventative alignment program of two checks per year, the cost for the checks would be between $100 and $200 per year for over-the-road service.

If the power unit averages 5.5 miles per gallon, and diesel fuel costs $3.24 per gallon, the rig’s fuel consumption would be a little less than $60,000 for the year. The vehicle, improperly aligned, would cost the operator an extra $1,822 just in fuel consumption. 

If the power unit’s average tire cost is $1,675 per year, based on 100,000 miles per set of steers and 300,000 miles per set of drives, then the operator could expect to save $590 in tire costs per year, per power unit. At the end of the year, per power unit, the operator could save around $2,412 for their $100 to $200 investment. 

Along with periodic vehicle alignment, Johnson recommends performing a total vehicle alignment every time a suspension or steering part is changed that affects alignment; as the final step in an accident repair process; when steer tires are changed; as a response to driver handling complaints; and when the straight ahead position of the steer wheel changes.

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