The Consequences of Improper Nail Hole Repairing

Tech International
There are two common mistakes made in repairing nail hole injuries in commercial truck tires. The first mistake is only plugging the injury. The second is only applying a repair unit to the inside of the tire and not filling the injury.
A proper nail hole repair is a combination of many important procedures, and is best performed by properly trained personnel.
Most tire manufacturers and the tire repair industry agree that two conditions must be achieved in order to accomplish a proper tire repair.
In basic terms, a nail hole repair requires that the injury be filled and the appropriate repair unit be placed on the inside of the tire for support and sealing of the inner liner. In other words, using only a plug or only a repair unit (patch) are not proper repair methods and could lead to further problems.
Showcased here are two examples that illustrate the problems created by improperly repaired tires.
Since the tire is not demounted from the wheel during this type of repair, it does not allow for complete tire inspection of the inner liner, or injury analysis.
In addition, many products that are used for plugging a tire — such as string-type repairs ®” do not vulcanize to the tire. This allows moisture into the injury, which can lead to rust on the steel cords and separation. Also, plug-only type repairs do not seal the inner liner. This will allow air pressure to leak through the injury resulting in an underinflated tire.
A sharp object penetrated the tire through the tread area. The tire lost air pressure causing severe deflection of the sidewall area. As a result, the injuring object once again contacted the tire (on the inner liner) near the bead. This created the internal damage that is circled in Photo 2. Notice that not only is the inner liner cut, but the penetrating object has also cut the body cord of the tire.
Obviously, this tire should not have been repaired. But the tire repair technician didn’t remove the tire from the wheel, and simply applied from the outside of the tire. The technician had no idea that the penetrating object created a second injury inside the tire.
If the repair technician was following industry recommendations and had properly inspected the tire’s inner liner, this tire would have been scrapped. By repairing this tire, the technician put the customer at risk — physically and financially. Fortunately, in this case, no accident resulted from this improper repair.

If the damage had been cleaned out with a carbide cutter and filled with a proper filler stem, this repair unit would not have failed.
The tire repair industry has continually stressed the importance of proper and complete repairs. Trucking fleets lose countless thousands of dollars each year due to tires that have to be scrapped prematurely because of improper repairs, and tires that should be scrapped because the repair technician didn’t fully examine the damaged tire.
Proper education and techniques can save your customers money, and make you a more valuable resource to them.®′