What do we mean by "alignment" anyway?

We define a vehicle as being "in alignment" when under load and at normal speeds, the vehicle and all its tires are traveling in the same direction.

Are tractors sometimes delivered out of alignment?

The truck manufacturers we've worked with tend to have excellent, well-maintained alignment equipment, together with highly trained technicians. And, new vehicles tend to be tighter than they are at any time during their useful lives.

So what's going on?

It's possible that the shop checking the alignment isn't as well equipped, hasn't calibrated its equipment as often or doesn't have as well-trained operators.

In other words, it could be a measurement error.

We can't count on the results we get from our alignment shop?

The vehicle, the measuring device and the person doing the measuring all affect alignment results.

While a new vehicle probably leaves the factory in near-perfect alignment, changes begin almost immediately.

Parts wear and get "broken in," things shift and settle. Think about a box of cereal. At the factory, they fill it right to the top. But over time, with transportation and other jostling, the contents settle a bit.

Vehicles "settle" too. There are lots of rubber parts, springs, nuts and bolts and other parts that gradually "settle."

Eventually, things "settle in" and stop changing so much, but as a rule, there's more change during the break-in period than at any other time in the vehicle's life.

And the measuring device?

All measuring devices need to be recalibrated periodically. Wear, shock and age can cause alignment equipment to go out of calibration, and when that happens, readings may no longer be accurate.

5 things to look for in an alignment shop:

*Reputation for good work
*Certification of technicians
*Cleanliness & orderliness of work areas
*Attitude of personnel
*Extra services available

What's the effect of the technician?

Some are more skilled than others. They may also be careful or careless, tired or alert, happy or discontented.

So, are you saying we shouldn't check and re-align our new trucks?

There are lots of things that change on a truck when it's new, and when you combine that with inevitable equipment and human errors, you may actually be doing more harm than good if you try to re-align a new vehicle.

When should a new truck be aligned?

Bridgestone and the Technology and Maintenance Council (TMC) recommended Practice RP 642A-2 suggest a "post break-in" alignment between 15,000 and 30,000 miles or 3 months, whichever comes first.

And after that?

TMC recommends subsequent alignments be done every 80,000 to 100,000 miles after the post break-in alignment.

We'd like to point out that this would be about the same interval at which you replace steer tires.

Is that the only time alignment should be done?

You should also check alignment if you observe irregular tire wear, if the driver reports steering or handling problems, if the vehicle has been damaged, or if components that affect alignment have been replaced.

Is it necessary to align all the axles?

Drive and trailer axle alignment can have a huge effect on overall vehicle alignment, and tire wear problems may show up on steers, but actually be coming from the drive or the trailer axles.

Many alignment experts rank drive axles as causing the most trouble, followed by trailer axles, with steer axles last.

Should a good alignment eliminate irregular wear?

Once irregular wear starts on a steer or trailer axle, you usually can't counteract it or make it go away. It just gets worse and worse.

If you put new tires on after you align, they should wear evenly, but your old tires are going to continue to show irregular wear.

Also bear in mind that there's a difference between a vehicle that's aligned to "spec" and one that's aligned to "tire wear."

Toe Change with Steer Axle Load

Because conditions of use can change alignment parameters, you may need to adjust alignment to fit your situation.

What does that mean?

The manufacturers establish alignment specs because that's the result of their experience of what works best, based on average conditions of use.

But your conditions may not be "average." You may haul much heavier or much lighter loads. You may have greater or less road crown along your routes. Or any other operational variable.

If you think about road crown, for example, it's trying to push the vehicle off the road onto the shoulder. If the vehicle were aligned for a perfectly flat road, the driver would have to be constantly applying force to the steering wheel to keep the vehicle on a crowned road.

So, alignment specs try to take things like that into account.

Sounds like the vehicle should actually be aligned on the basis of tire wear.

In a way, that's really the goal. After all, a misaligned vehicle wastes rubber, fuel, driver energy and driver attitude - all at the same time.

If we go back to our original definition, where the vehicle and tires are both going in the same direction under load and at normal speeds, a well-aligned truck would waste very little of these things.

So how do we know if our trucks are truly properly aligned?

TMC makes the point over and over again: tire wear. Your tires will tell you whether your axles are properly aligned by how long they last. In fact, according to TMC, correct inflation pressure and correct alignment are the two biggest factors in long tire life.