Where does rubber on the road come from?
Peggy Fisher: "In 1995 and 1998, TMC task forces, together with state Departments of Transportation, collected roadside tire debris at 13 locations across the nation. "We were very careful to count only larger scraps - to reduce the possibility of counting the same tire twice - and all the pieces were examined by tire engineers to determine tire type and cause of failure."

What kinds of things did you learn?
"Over 1/3rd of all roadside tire scraps in our surveys came from passenger and light truck tires, not heavy duty truck tires. "That's especially significant, because the number of retreaded passenger and light truck tires is almost zero. So, these tire scraps couldn't be the fault of the retreading process."

Peggy Fisher is a fleet tire consultant, who for nine years was president of Roadway Tire Company, a subsidiary of Roadway Express, Inc. Before that, she spent 10 years as Roadway's manager of tire, trailer and dolly maintenance. She has chaired three different TMC tire task forces, and writes on tire-related issues for a number of industry publications.

How was the 1998 survey different?
"Even though researchers picked up scrap on the same dates and on the same stretches of highway, there was much more of it in 1998. "We attribute this to two factors: First, shortly after the original count in 1995, the federally mandated 55 mph speed limit was repealed. "And, in 1998, it was an extraordinarily hot summer in some of the places we were collecting scrap. When we eliminated all locations where speeds and temperatures were up, there was no difference in the amount of scrap."

"The overwhelming majority of tires studied, 86% of them in 1998 and 90% in 1995, failed because of underinflation, not because of retreading." - Peggy Fisher

Indicates the results are sound, doesn't it?
"We're certain of it. We collected nearly 2/3rds more scrap in 1998, but the ratios of the different types barely changed: It was still over 1/3rd passenger and light truck, with the rest from truck and bus radials."

What were the actual causes of failure?
"In most cases, it was underinflation. Tires were simply run at too low an air pressure for too long, or they encountered road hazards that punctured them and caused them to lose air pressure. "Underinflated tires flex too much and run too hot. That's what destroys them. Higher speeds simply mean they get hotter faster, and higher outdoor temperatures have the same effect. "The overwhelming majority of tires studied, 86 percent of them in 1998 and 90 percent in 1995, failed because of underinflation, not because of retreading."

That suggests that maintaining correct inflation pressure could solve the problem, couldn't it?
"It certainly could help. But there will always be road hazards, and those accounted for about a quarter of the debris. And don't forget that over a third of the scrap came from 4-wheelers, over which the trucking industry has no control."

What kinds of tires were prominent in the study?
"Rib tread patterns were most common, and retreaded tires represented most of the tires. Since most fleets use rib tires on trailers, that came as no surprise."

Marvin Bozarth joined the International Tire & Rubber Association in 1990, and has been its executive director since 1991. Marvin's entire career has been in the tire and retreading business, and he is a past chairman of the Retread/Repair Industry Government Advisory Council, as well as the current editor of ITRA's Tire Retreading/ Repair Journal.

Doesn't the prominence of retreads suggest a problem with retreads?
Marvin Bozarth: "Not at all. There are reasons there are so many trailer tires and retreads in the study: First of all, trailer tires are at the tail-end of the vehicle. "If a nail or a screw is lying on the road sideways, chances are you can run across it with no significant damage to tires. But the first tire to hit it, probably a steer or drive tire, makes that nail jump up and stand on end, just in time for it to be driven into a trailer tire."

"When you see a strip of tread along the road with cord hanging out of it, it was the casing that failed, not the retreading process." - Marvin Bozarth

How does that relate to retreads?
"Probably 2/3rds or more of trailer tires are retreaded. So, it's retreads that are getting hit by most of the nails and other road hazards. "We also know that trailer tires are usually the most-neglected tires on the truck. The trailer may not even belong to the fleet or driver who's pulling it, so they may ignore inflation pressure checks. "Since these tires tend to be retreads, they are the ones most likely to have an underinflation problem. It's not that they're retreads, but underinflation that is the likely cause of trouble. "Finally, most of the medium truck tires on the road are retreads. Over half the replacement tires sold each year are retreads."

What would happen if new tires were substituted for the retreads?
"In my experience, nothing. Time and time again, I've seen a fleet decide to stop using retreads, only to find their tire problems don't change. I wish I could have worked with them and instituted a good inflation pressure maintenance program, because I know I could have saved them a lot of money."

So you believe underinflation is the culprit?
"I know it. Whether caused by neglect or a nail, underinflation causes tires to run way too hot. That makes them come apart. In our tests, heat can cut the strength of the bond between rubber and steel in half. Centrifugal force just pulls the whole belt package right off the tire, because heat has weakened that bond. "The bond holding a new tread onto a retreaded tire is between rubber and rubber. When you see a strip of tread along the road with cord hanging out of it, it was the casing that failed, not the retreading process."

Is retreading never at fault?
"It's very rare that the retreading process fails. However, sometimes casings are retreaded that already have internal damage, making them more susceptible to failure, but even then, it's only when they get hot."

In other words, they shouldn't have been retreaded?
"That's right. It takes a lot of skill to determine whether or not a casing will make a good retread. These days, the inspector is getting help, from all kinds of new non-destructive testing equipment, including electrostatic, ultrasound and shearography analyzers. "The idea is to help the inspector see invisible damage."

Does it work?
"It helps. But it still takes a skilled, experienced inspector to interpret what the machines say. I don't think a machine will ever be able to cover that aspect of the process."

Harvey Brodsky has been part of the retreading industry since the early 1970s. Since 1981, he has been managing director of the Tire Retread Information Bureau (TRIB), an organization dedicated to supporting the retreading industry - and dispelling myths about retreaded tires. Practicing what he preaches, Harvey has used retreaded tires on his personal cars for over 25 years.

What is the retreading industry doing about the problem?
Harvey Brodsky: "Besides the things that Peggy and Marvin talked about, finding the cause and improving casing selection, we're also attacking several problem areas: "First, we're doing everything we can to educate both truckers and the general public about the real causes of the road alligator problem. People see scrap rubber along the side of the road, and often wrongly assume the retreading process is at fault. "Second, whenever we hear of an incorrect statement about retreads anywhere in the media, we respond, with facts, and try to correct those misconceptions. We're constantly sending information packets, letters, press releases and other information to media around the country."

"Research shows retreaded tires are no more likely to fail than tires that haven't been retreaded." - Harvey Brodsky

Is that working?
"The situation is starting to change. One of the most exciting recent developments was in Virginia, where the state police were ordered to determine whether the state should establish standards for retreaded tires. "Their study concluded that 'the establishment of state standards would have little, if any, impact on the problem' of rubber on the road. And that was because their own research shows retreaded tires are no more likely to fail than tires that haven't been retreaded."

TRIB makes stickers like these available to fleets, retreaders and others who want to help stop rubber on the road.

What else are you doing?
"Knowing the cause of rubber on the road doesn't do any good if you don't try to do something to prevent it. That's why we work constantly to promote our'Pump 'em! . Don't Thump 'em!' program.

"The only way to know your tires are properly inflated is to use an accurate gauge - and use it correctly - then adjust the cold inflation pressure to the correct level for the tire and load. Tire billies, hammers, kicking the tires or just looking at them simply doesn't work.

"If we could get everyone - truckers and passenger car drivers - to do that, we could make most of our roadside alligators go away."

Editor's Note: The International Tire & Rubber Association Web site is located at www.itra.com, and the Tire Retread Information Bureau (TRIB) can be found at www.retread.org. TRIB also maintains a Web site specifically about rubber on the road at www.roadgator.com.