RealAnswers Volume 4 Issue 3

We’ve come to the last letter in our “S.M.A.R.T.” acronym, “T,”
for “Track performance of every tire, throughout its useful life.”
Why? What good is all this extra paperwork?

Quite simply, what you can learn from tracking tire performance is
that the lowest price tire isn’t always the least expensive. And,
you may be able to change your cost per mile for the better
without changing the tires you use.

What’s the benefit of tracking tire performance?
First, it’s the best way to determine whether you’re getting what you pay for. It’s also the best way to compare different tire brands and models. A good tire tracking program can also help you with tire selection, and help you control maintenance, repair and retreading costs.

What kinds of things should we track?

Ultimately, what you want to know is your tire cost per mile. People do this in lots of different ways. Some track cost on new tires only. Some include retreads. Some add in tire maintenance, repairs, retreading, casing values and even disposal fees.

Whether you make it complicated or simple, what you want is a number that represents your cost

CALCULATING TIRE COST PER MILE

TIRE COSTS:
[Acquisition price + F.E.T. +
Mounting & Balancing (initial)]

+ [Repairs + Maintenance costs +
Mounting & Balancing (after repairs)]

+ [Retreading + Mounting (after retreading)]

+ [Tire disposal fees
(or – Casing trade-in value), etc.]

MILES:
[Original tread mileage + Retread #1 mileage + Retread #2 mileage + Retread #3 mileage, etc.]

While that would be best, it may not be practical, especially for a large fleet. After all, the cost of tracking is a factor too.
It’s difficult to say just exactly how many tires you should track. As a rule of thumb, we suggest this: keep records on at least 30 vehicles, or 10 percent of the vehicles in your fleet, whichever is greater.
So, if you have 500 tractors, we’d recommend tracking the tires on 50 of them. If you have only 100 tractors, we’d recommend you track the tires on at least 30.

What should we measure?
One of the most basic measurements is rate of wear, in “miles per 32nd.” This is the number of miles the tire has gone so far, divided by the number of 32nds of tread worn away.
Tires, like most things on a truck, tend to wear more slowly as they get older. So, if you calculate miles per 32nd at regular intervals, you’ll find that miles per 32nd increases with wear.
And, if you multiply miles per 32nd by the number of usable 32nds (remember to deduct your normal removal tread depth from original tread depth when you make this calculation), you can project the total number of miles you might get from the tire, based on the average wear rate at that point.
Bear in mind that projected mileage, like miles per 32nd, tends to increase as the tire wears. At any given point in a tire’s life, you can calculate miles per 32nd:

Then why calculate it?

Because once you’ve accumulated data for various tires on your vehicles, this sort of “snapshot” can tell you if a tire is wearing faster or slower than normal. Or, if a new make or model of tire is performing better or worse than those you have used in the past. You can also use it to project removal mileage, one of the crucial measures of a tire’s worth.

The best thing about this kind of recordkeeping is that it tells you things early, and throughout the life of the tire. You don’t have to

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What else should be measured?
It’s a very good idea to record inflation pressures along with mileage and remaining tread depth. You may discover that one tire, for example, is losing air, perhaps at a slow rate. That should be investigated.
If all tires on a vehicle consistently come in low or high, the driver might have a miscalibrated gauge, or may be deliberately reducing inflation, trying to soften the vehicle’s ride.
Of course, you’ll also want to note any maintenance or alignments done, along with the odometer or Hubodometer readings.
You can also experiment (within manufacturer’s recommended inflation pressure limits) with the effect of higher or lower inflation pressures on overall tire wear and irregular wear. As long as you stay above the minimum inflation pressure required, you may find that there’s an optimum inflation for your operation.

How will we know?
At any given time, you want the highest possible miles per 32nd. If you have that data and the inflation pressure data, you’ll be able to tell what’s working best for you.

When should this be done?
Chances are, the most convenient time will be during regular PMs. In fact, we’d recommend that you check the tires first. That way, it may be possible to correct a tire condition while the vehicle is still in the service bay.
The other good thing about doing tire tracking during PMs is that your data collection will be consistent and regular. As we’ve said all along, consistency is the recipe for regular, even wear.