PEGGY FISHER: Inflating tires is not rocket science — or is it?

AKRON — One undisputed fact in the commercial tire world is that maintaining tire inflation pressure is the single most important thing anyone can do to improve tire performance and reduce tire cost per mile.

This is because it is the air in the tire that supports the vehicle and its load and absorbs the shock as well...not the tire. Tires are simply the containers that hold the air.

If tires are underinflated, they will wear fast, the steel cords they are made of will fatigue and break, excessive heat will develop, which will destroy the tires, and they will consume more fuel.

Underinflated tires also will provide drivers with a sloppy road feel and will have a tendency to skid in turns creating a dangerous handling situation.

Overinflated tires have reduced shock absorption qualities and will provide a hard, rough ride. They are also more vulnerable to cutting, impact and shock damage.

Both over- and underinflation change the tire's footprint, which will affect the traction of the tire too.

Everyone talks a lot about the importance of maintaining proper air pressure in tires, but in reality there is much apathy and a general lackadaisical effort in actually attaining it. It seems this is an area where there is more hot air than action.

One of the cool things about TPMS 2.0 products that advise fleet personnel of tire problems in addition to truck drivers is that now fleet managers have visibility of their tires, even though they may be hundreds of miles away.

If a tire is serviced, fleet managers can see from behind their desks what tire pressures were before service was performed as well as after.

Many fleet maintenance managers have been surprised to find that their tires are not being inflated to the pressures they specified by both their own service technicians as well as by their tire dealers' technicians.

In the past couple of months, I have visited several tire dealers who are providing mount/demount services for their commercial tire customers. Without fail, every single dealer was unable to inflate tires consistently to the pressures requested by their customers.

Airing it out

You are probably sitting there saying, "Oh, come on. How tough can inflating tires be?"

Well, it's not rocket science, but apparently it's a lot tougher than most people think.

During my visits to dealers and to their fleet customers' locations, I found that a large percentage of pressures in recently mounted tires ranged from 5 to 12 pounds off on average.

Many tires were right on the money, but a large percentage of them were off.

Why is this? In digging around, I found that there were several reasons.

The first was rather simple. The technicians mounting tires did not know what the customers' requested pressures were.

At one location, a particular fleet customer had two pressures it requested, one for steer tires and one for all other tires of a particular size. For some reason the dealer's technicians thought that the drive and trailer tires should have pressures higher than the steer tires and arbitrarily came up with pressures they believed were right for these tires.

Instead of inflating steers to 110 psi. and rear tires to 95 psi. as the customer requested, the dealer personnel inflated steers to 90 psi. and drives and trailers to 110 psi.

At another location, although the fleet specified 110 psi for steers and 100 for all other tires, all tires were inflated to 100.

In both situations, steer tires were underinflated significantly right out of the box, and the TPMS 2.0 systems issued warnings immediately.

The second problem, and the most common, was the variation in inflation pressures that occurred due to lack of proper air regulation at the tire cage.

Some dealers did not have regulators on their air lines at all. The technicians simply used their service gauges to check when the tires were inflated to the targeted pressure.

Unfortunately, their service gauges were way off. Other dealers that had regulators found it necessary to change the regulated air pressure constantly on their cage to accommodate different size tires and air pressure specifications.

The regulators did not retain their accuracy, and no one bothered to check them.

Maintain equipment

I also found that service technicians who were responsible for inflating tires at a fleet's location did not have properly calibrated service gauges or regulators on their service trucks so that their maintenance of the fleet's tires was far from good.

Obviously from these experiences, it is apparent that having the proper, well-maintained equipment is crucial to attaining proper air pressure.

If you are providing mounted tire programs and inflation pressure maintenance for your fleet customers, make sure that you have the right, properly maintained equipment to do the job and that you meet Occupational Safety and Health Administration (OSHA) requirements.

Start with a good air compressor that is properly maintained and will provide the volume of air you need to your service area. It may be necessary to install a holding tank in the service area to increase the volume available there.

Ensure that the air lines are equipped with water filters and pressure regulators. The connection for the air line used to inflate tires should never be taken from the bottom of a run where water may accumulate.

Ideally an air dryer is great to remove unwanted moisture from the air lines but even with an air dryer, drains should be checked periodically.

If an air dryer is not available, air lines should be drained regularly. Facilities in humid climates may need to drain their lines daily, while others may only need to drain them weekly.

Moisture in the air lines will shorten air tool and pressure regulator life as well as steel, radial tire life. Any moisture that is in the air lines will permeate tire innerliners and attack the steel cords.

Also, lubricators must not be plumbed into air lines that are used to inflate tires.

In addition to safety cages, air regulators preset to the desired value are an OSHA requirement. They should be checked for accuracy weekly if their pressures are never changed.

And they should be checked for accuracy every time the pressure is changed. Regulator manufacturers recommend that pressure always be increased from a lower setting to the final setting for consistent results.

Regulators can lose their accuracy on their own due to wear of their mechanical parts and should be replaced annually if used in moderation.

If regulators are in constant use, then consider replacing them every six months.

Placement of the regulators is also important. They will not do a very good job if they are situated far from the point of inflation.

They should be at most 20 feet away from the inflation hose. Prior to the emergence of the zipper condition in radial truck tires, it was a common practice to mount the pressure regulator on the tire inflation cage.

This is not such a good idea now, since the technician should be able to cut the air off to the tire if he detects a zipper condition in a tire being inflated.

Therefore, you should consider mounting the regulator and a shut-off valve or hose quick release coupler on the wall between 10 and 20 feet away from the cage. (I know many technicians prefer that it be located right next to the door so they can hit it on their way out.)

If you routinely are inflating tires to two different pressures, consider using two tire cages with two regulators set at different pressures to minimize the number of times the regulator has to be changed. This will save wear on the regulator and labor in recalibrating it every time the pressure is changed.

Use air lines with a minimum of 3/8th-inch diameter in and out of the regulator to allow for optimum air flow.

OSHA also requires that air lines be long enough to allow the technician to stand clear of the trajectory and that clip on air chucks be used to attach the air line to the tire.

(There are several automatic inflation kits on the market today that you can get from your tire supply distributor, which will provide you with the safety and performance you need for your facility.)

Compressors and inflation equipment on service trucks should be maintained to the same standards found within your service center.

Technicians at both your service facility and in service trucks must be provided with good truck tire pressure gauges.

Gauges should be checked weekly at a valve stem adapter built into the air line at a pressure regulator that is checked weekly against a master gauge.

Gauges that are off by 5 percent or more should either be recalibrated or replaced.

Don't forget to have your master gauge checked annually to ensure that it is correct too! A master gauge has a rated accuracy of +/- 2 percent in the middle of its range.

That means that if a 0-200 psi gauge reads 100 psi, the actual pressure will be between 98 and 102 psi. If you don't have a master gauge check station, you can purchase a complete assembly from tire supply distributors.

Last step

After the tires have been inflated, they always should be checked with a calibrated service gauge before installing the valve cap and returning the mounted assembly to the customer. This is the last step to ensuring tires have the proper inflation pressure.

And finally, provide a fool-proof method of communicating your fleet customers' inflation specifications to your technicians.

This may be in the form of a book or three-ring binder, a laminated paper that fits in the glove compartment of your service trucks, printed on work orders, or posted online where it can be accessed by tablets and smartphones.

(Some TPMS 2.0 systems provide target pressures and instructions to technicians for adjusting inflation pressure in tire alerts to help ensure the proper pressure is applied.)

Whatever works for you and your service team is fine just as long as it is correct. You don't want to lose service business just because your technicians didn't know what pressures your fleet customers specify.

So inflating tires is not rocket science. But how well is your dealership performing in this area?

If you are providing mounted tire programs to your fleet accounts and technicians are mounting/demounting tires in your shop, go out right now with a good air gauge and check 10-12 recently mounted tires and see what you find.

Don't be satisfied unless you find that all the tires have been inflated to their proper pressures as specified by your customers.

If you find yourself dissatisfied, take the necessary steps to blast off your commercial tire service performance.

Peggy Fisher is president of TireStamp Inc. and is based in Troy, Mich. She can be reached via e-mail at [email protected].