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.