by popular DEMAND

 

 

 

 

 

 

 

 

 

 

 

The story goes that a prison warden had a sign above his desk: “Good judgment is the result of experience. Experience is the result of bad judgment.”
A scrap pile may be the repository of bad past experiences, but it can be a great source of information for the future.
Misapplication, not choosing the right tire for the job, may sometimes be obvious – in hindsight. The trick is to use what you learn in the scrap pile to help you make better tire selections in the future.

 

 

How do we know we have a misapplication?
Generally, the evidence will be a tread that is wearing incorrectly, wearing too fast, or tread damage that is characteristic of being in the wrong place at the wrong time.

 

 

 

For example?
Believe it or not, our first example started as a Bridgestone R227 unidirectional steer radial. The way it’s chewed up, you can barely see the unidirectional pattern.

What caused this?
This R227 ran a lot of miles off-highway. In fact, it was used in oil-field service in West Texas, and had to contend with “caliche,” or crushed rock oil well access roads.
Sharp-edged rocks cut and chipped the tread because this tire is designed for long-haul on-highway service. Neither its tread compound nor its pattern is suited to this kind of work.

Why would someone use an on-highway tire that way?
They might not have known. Or maybe they thought they weren’t going to be taking any trips off the highway, then their situation changed.
It’s hard to make absolute determinations. We’ve seen cases, as on caliche roads, where almost any off-highway travel requires switching to on/off-highway tires. And, we’ve seen cases where operators did 10 percent or more off-highway work, and had no trouble with cuts, chips and chunks.

 

 

 

 

 

 

Razor-sharp chunks of crushed rock on oilfield access roads severely cut and chipped the tread of this R227.

 

 

 

 

 

 

What’s the difference?
Some trucks used in construction drive across hard-packed earth that’s almost as good as asphalt. And dry surfaces tend to cut tires less than wet ones, because water acts as a kind of cutting lubricant.
On some ice-covered roads in northern Alaska, operators find their tires actually last longer in winter, because ice, like hard-packed earth, produces a slippery, but otherwise excellent road surface.

 

 

 

 

This tire shows somewhat less off-highway damage, but notice the long scratches that suggest it was spun on gravel or rock.

 

 

Your first example was kind of easy.
Not all of them are. In the next picture, you’ll see more subtle damage. In this case, another clue to misapplication is the “scratches,” especially in the center of the tread. These suggest the tire was spun.

 

 

The tread pattern may not have been aggressive enough for gravel or rock, leading to the spinning. Inflation pressure may have been too high, preventing the tire from digging in. Notice the little slices into the tread, and pieces of tread that are completely gone. They may be small flakes, or big chunks. This shouldn’t happen in normal highway service, but is very common when an on-highway tire is used off-road.

Why not use on/off-highway tires for everything, just to be safe?
Several reasons, actually. On/off-highway radials encounter lots of obstacles. They need to be flexible to resist punctures.
So, they’re made to envelop rocks and other hazards. They’re also made with tread compounds that are really tough, to fight chipping and cutting.
At interstate speeds, this can cause on/off-highway tires to run hotter. Heat is the mortal enemy of tire casings, and also accelerates tread wear.
Take a look at the next example.

What happened here?
This is a real heart-breaker. It’s a brand-new L317
on/off-highway radial. It was on a new tractor being
delivered to a customer, and the tractor was being
hauled “piggyback.”
The L317 has a maximum speed rating of 55 mph,
but this one ran for many hours at much higher speeds.
Heat “cooked” the tread and casing, turning the tread
“spongy,” and creating huge voids under the lugs.
So this was the wrong tire for the load and speed.
The driver could have prevented this, but may not have
known about the potential for the problem.
Most on/off-highway radials are restricted to speeds of
65 mph or less, while most of their on-highway cousins
can be used at sustained speeds of up to 75 mph.

 

 

 

 

 

 

 

 

 

 

When on/off-highway tires are run at high speeds, they can get too hot, destroying both tread and casing.

 

 

 

What if we never go off-road or use off-road tires?
You can still have misapplications. Our next example has Bridgestone’s Defense Groove™ feature – a tiny groove near each shoulder – that is very effective in fighting irregular shoulder-edge wear in long distance line haul work.
But here, you see that it’s torn and chipped in many places.
That can result from using a tire designed for interstate work in an urban setting.
Constant turning and maneuvering, along with encounters with curbs, can tear grooves like these to shreds.
Short hauls and city driving tend to produce rapid tire wear, so the irregular wear-fighting qualities of a shoulder groove may be unnecessary. That’s why radials designed for urban service, like the R250, often eliminate it.
Without that thin shoulder rib, there’s nothing to tear away.
Of course, using such designs in long-distance line haul could equally be considered misapplication.

 

 

 

 

 

 

How can we avoid these problems?
Work with your tire supplier to choose the right tire for your application.
It sure would be simpler – for both tire manufacturers and customers – if just one tire worked equally well for every application. Unfortunately, service requirements are so varied that we need lots of tires, to optimize performance in a variety of environments.
So, keep inspecting your tires and scrap to see if misapplication symptoms appear. And, of course, learn from your experience.

 

 

 

 

Editor’s Note: This time, we looked at “misapplication.” Next time, we’ll see some results of “mismaintenance.”
Small grooves near the shoulder edge may combat irregular wear in line- haul work, but can be severely damaged in urban hauling.