Truck Topics
A Look at Retreads
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Mar 12, 2008 - 11:24:51 PM

As every owner-operator knows, fuel costs are the biggest expense of doing business, with tire expense coming in second.With the ever-increasing cost of fuel, every owner-operator in expedited trucking is concerned with squeezing every last mile out of that precious liquid.

But, many owner-ops may be overlooking a savings in thenumber two area of expense - tires.  A new set of tires for a six-wheeler, let alone an eighteen-wheeler, can be a substantial investment.  Doesn't it make sense to consider an alternative that might save you half that money?  Have you looked into today's retreads? 

In years past, retreads admittedly had a serious image problem.  They were frequently blamed for blowouts, tread separations and the ubiquitous "gators" found along the nation's interstates. 

However, investigations over time have determined that the rubber debris found along the roadside is primrily casing material from blown tires that were probably underinflated or otherwise abused.

To be sure, in the past there small, independent tire retreaders who sometimes delivered a product of dubious quality.  But, because of rapid consolidation in the retread business, modern retread plants are mostly owned by big tire makers (along with some independents), all of whom are using high-tech equipment.  There are approximately 900 retreading plants in North America.

According to the Tire Retread Information Bureau (TRIB), retreads are used by small package delivery companies with guaranteed delivery times, including the U.S. Postal Service, on commercial and military jets, by most school bus operators, taxis, and many other types of vehicles. 

TRIB also states that retreaded truck tires represent a savings of over $3 billion dollars annually for truckers and trucking companies in North America.  Approximately 18.6 million retreaded tires were sold in North America in 2006, with sales in excess of $3 billion. The majority of these were medium truck tires.

Today's new tires are built to be retreaded, says tire expert Peggy Fisher, President of US Operations for TireStamp, a tire data analytics company. She states that radial tires were constructed with retreading in mind - a big plus over the bias-ply tires in the '70s.

Retreading lets you reuse the good parts of the tire instead of buying all new, saving about half the cost of new tires. Retreads are not only cost effective, but they are also dependable, reliable and safe.  Retreads are also environmentally friendly, requiring only about one-third of the petroleum used in a new truck tire.

Many experts agree that advanced materials and tire construction have resulted in a decreased product failure rate for retreads that is now as good or better than new tires.  And mileage-wise, TRIB states that with proper maintenance and care, retreaded tires will provide the same amount of service as comparable new tires

.

Retreads' tread life varies from the same as a comparable new tire to 75% of a new tire. 

When is a tire too old for retreading?
The retreadability of a worn truck tire casing is not solely a function of its age. The condition of the casing is a function of a number of things: 
*What was its application?
(Long haul, P&D, etc.)
*Type of equipment
(Single, Dual axle tractor, Straight truck)
*How well was the tire maintained?
(Overloaded, underinflated, run flat)

It's the retreader's job to determine the retreadability of the old  casings through a visual inspection as well as the use of sophisticated testing equipment.

The retreading process
Basically, there are two systems used to retread a tire, Mold Cure and Pre Cure.

The reason both systems exist is because of the economics of operating a retread plant and have nothing to do with the quality of the finished product. Each system has unique advantages but both systems produce equally good retreaded tires.

The goal of retreading is to rebuild the tire, removing the tread from the casing and replacing it.

The initial steps in retreading a tire are the same regardless of which retreading system is used. These steps are:

1. Primary Inspection.
Each tire is subjected to a very rigorous visual inspection. Inspectors may be assisted by the use of various non-destructive sophisticated inspection equipment available in the retread industry. As many as 85% of passenger tires are rejected. The acceptance rate for truck tires is higher due to the better care taken for and the stronger construction of a truck when compared to a passenger tire.

2. Buffing
After inspection, tires have the old tread mechanically removed on high speed buffers. This is accomplished by using an abrasive wheel to cut the tire down to size.  In some retreading facilities, the process is completely automated.

The tire type is input into the computer which has data on the exact dimension the tire must be buffed down to in order to reach the outside of the casing. . The surface is then textured with a grinding wheel that produces the correct texture for the new tread vulcanizing process.

3. Application of new rubber in the tread area. Here is where the systems differ.
a. In the pre cure system, the tread rubber has already been vulcanized with the new tread design. The buffed tire has a thin layer of cushion gum wrapped around the tread area and the pre cured tread is then applied. The cushion gum serves to bond the pre cured tread to the tire. The tire is then placed in a curing chamber and the pre cured tread becomes adhered to the tire through a vulcanizing process very similar to that used in new tire construction.

b. In the mold cure system, unvulcanized tread rubber is applied to the buffed tire. The tire is then placed into a rigid mold which contains the tread design in the tread area. The mold is heated and the rubber in the tread area vulcanizes and adheres to the tire with the new tread design molded in. Again, this vulcanization process is very similar to that used in new tire construction.

Note: Both systems require a combination of time, heat and pressure to create the vulcanization of the new rubber to the tread area of the tire.

Final inspection
The retreaded tire is subjected to a final inspection. This inspection insures that only tires that meet industry quality standards are allowed to leave the retread plant.

Trimming and painting. The retreaded tire that successfully has passed the final inspection, is trimmed to remove any excess rubber and painted. It is then ready to return to full service and a second (or third) life as a safe and economical alternative to high priced new tires.

Simple tips for all tires
*Check tire pressure regularly using a good gauge that is calibrated often. Inflation pressure cannot be accurately estimated by kicking or thumping the tire.

*Tire pressure should always be checked when a tire is "cold" - before a vehicle has been driven, or driven less than one mile.

*To keep air in, keep wheels clean and properly lubricated. Make sure valve stems and cores are in good condition.