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Just as with irregular wear prevention, scrap analysis can be an incredibly effective
way to improve tire performance – if you have good records. That’s why we’ve linked
irregular wear and scrap, because though we’ve come to the end of our series of articles
on irregular wear, we’re starting a new series, on scrap analysis. That last letter in our “S.M.A.R.T.” acronym, “T,” for “Track performance of every tire, throughout
its useful life,” applies to scrapped tires as well, as we’ll see.
What can we learn from scrap tires?
If you learn to “read” your scrap tires, you will find they can often tell you much about the kind of life they’ve had, and what you can do to give them a longer life in the future.

 

 

 

 

 

 

How often should we do a scrap analysis?

 

 

 

Ideally, you would analyze scrap tires as soon as they are pulled from service.
This tire is soft and spongy, but its smell is what gives it away. Apparently, it sat in a puddle of diesel fuel.

 

Why not wait until we’ve accumulated a bunch?
While you can do that, there are risks. First, you may never get around to analyzing your scrap, or the pile may grow so large that the task becomes too daunting.
Second, the reason for sending the tire to the scrap pile will most likely be freshest in your mind at the time it’s removed from service.
Third, you may find some tires that can be repaired or retreaded and returned to service. If you send them to the scrap pile, by the time you get to them, rust may have done its dirty work, preventing you from saving them.

How do we “read” a scrap tire?
Begin by positively identifying it, then make your best judgment about why it found its way into the pile.
Good record keeping forms will help, and we’ve included some here that you can photocopy and use. You’ll also find these available on the Bridgestone website.
Forms like these are available from your Bridgestone representative, or you may download them from the Bridgestone website in the Real Answers magazine section, at www.trucktires.com.
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RealAnswers DOWNLOAD

Double-click on icon to the left to view in browser. To get a printable version of the Vehicle Inspection Form, right click(windows) or hold click(mac) on icon and choose "save target as"or "save to disc" to save to your cpu. Requires Adobe Acrobat Reader 4.0.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

What should we look at first?
Begin by getting basic information on the tire. If you brand your tires, you’ll want that number so you can access your PM and vehicle inspection data.
If you’re using a computerized system,
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that may be all you need to pull in all the other tire information, like manufacturer of casing and retread, size, tread pattern, DOT numbers, etc. Otherwise, you’ll want to record that data too.

What good is the DOT number?
The last three or four digits of the DOT number tell you when the tire was made. You’ll want to know this to determine the age of a casing, and for warranty purposes.
The last digit is the same as the last digit of the year the tire was manufactured, and the preceding two digits tell you the week of that year, from 01 to 52.
This year, some manufacturers are adopting a new, four-digit system. The last two digits represent the year, and the two that precede them, the week.

What’s next?
The next step is to do a thorough and systematic examination of each tire to determine its “cause of death.” It’s best not to jump to any conclusions. Examine the tire thoroughly, using a consistent method, and when you’re done, decide why it’s scrap.
Wear gloves to protect your hands, use a strong light or flashlight, and look at the whole tire, inside and out. Start with the tread, and work your way down each sidewall to the beads, going all the way around the circumference. An awl will be helpful for probing damage.
Look inside, again, moving from the area under the tread to the beads. Note anything unusual. Any repairs, any obvious damage.
Look at the color of the rubber. Smell the tire (you may be surprised what you learn). Once you’ve finished, make your best guess as to the reason it’s scrap.

Guess?
Sometimes, it will be hard to determine exactly what caused a tire to end up in the scrap pile. Sometimes, there will be more than one possible reason. As you become more experienced, it will be easier to recognize common causes. Always look for the most likely cause.
And, use your reference materials. The Maintenance Council (TMC) publication Radial Tire Conditions Analysis Guide (available from TMC, 703-838-1763), and the Bridgestone video, Saving Through Scrap Tire Analysis, can help you understand the conditions you observe and the reasons they occurred.
Then, write down the “condition code.”

 

 

 

 

 

 

 

Why use condition codes?
Condition codes, which are listed at the bottom of the form, will be very valuable when you do statistical analysis on your scrap.
They also help you standardize the way you categorize damage conditions. If one person calls a puncture a “puncture” and another calls it a “nail hole,” you may miss trends in your data later on, because you’re identifying a single type of damage two different ways.

 

 

 

 

 

 

 

 

 

 

 

 

 

How can we use all this information?
Here’s an example. In our first pair of pie charts, we see that although 255/70R22.5 tires represent only 15 percent of the wheel positions in this fleet, they represent 35 percent of the scrap. In other words, too many of them are hitting the scrap pile.
Why is that?
The other charts give us a clue. Here, we see that of the 255/70R22.5 radials in the scrap, 68 percent of them are there because of sidewall damage. Now
Although 255/70R22.5 radials make up only 15 percent of this fleet’s tires, they make up 35 percent of its scrap.
we’re beginning to get an idea of what’s going on.
On further examination, we see that of that 68 percent, nearly three-quarters of those tires got their sidewall damage from curbing.

 

 

 

 

 

 

 

 

 

 

So what’s the conclusion?
There might be several: for one thing, if these tires don’t have sidewall protector ribs, we might consider switching to a tire that does, to provide extra protection against curbing. It might also be an application issue, perhaps involving “low-boy” construction trailers.
We might also consider some driver education work to explain how curbing can be avoided. And, we might add auxiliary mirrors or other devices that could make it easier for drivers to see when they’re getting too close to curbs.
Would we have learned all this without scrap analysis? Perhaps. But the charts provide pretty conclusive indication of what’s going on.

 

 

 

 

 

 

 

 

 

 

 

 

Over the next few issues of Real Answers, we’ll look at some of the different reasons tires show up in the scrap pile, and what you can do to prevent it.