QuestionI HAVE A COUPLE OF QUESTIONS FOR YOU REGARDING STEEL BELTED RADIAL TIRES. MAINTENANCE RECORDS ON THIS TIRE SHOWS THAT IT WAS PLUGGED 4 TIMES. THERE WAS NO MENTION OF REMOVING THE TIRE FOR PATCHING OR BALANCING. THE STEEL TRACKING WAS VISIBLE TO THE EYE AND THE TREAD DEPTH WAS APPROXIMATELY 1/16 TH OF AN INCH. IS IT TYPICAL THAT A TIRE IN THIS CONDITION WOULD RUN RISK OF TREAD SEPARATION? THE SEPARATION IN THIS TIRE WAS IN THE AREA OF THE PLUGGINGS. IS IT YOUR OPINION THAT THIS TIRE WAS RUN UNDERINFLATED? WOULD TEMPERATURE OF THE PAVEMENT OR SPEED OF THE VEHICLE CONTRIBUTE TO THE SEPARATION?
AnswerDonna,
Let me divide this up:
1) MAINTENANCE RECORDS ON THIS TIRE SHOWS THAT IT WAS PLUGGED 4 TIMES. THERE WAS NO MENTION OF REMOVING THE TIRE FOR PATCHING OR BALANCING.
Plugging a tire is an unacceptable repair method. The Rubber Manufacturers Association - an industry trade group - has published tire repair guidelines in conjunction with both tire manufacturers and repair material manufacturers. Here's a wall chart that they publish so that it is clear what is repairable and what is not. It also contains the procedure for a proper tire repair - and plugs are specifically excluded.
https://www.rma.org/publications/tire_service_professionals/index.cfm?PublicationID=11303
The reason plugs are not acceptable repairs is that plugs tend to develop leaks more often than they should. They also don't "bridge" the injured area like a reinforcing patch does. The fact that there are 4 plugs just multiplies the problems associated with plugs.
2) THE STEEL TRACKING WAS VISIBLE TO THE EYE AND THE TREAD DEPTH WAS APPROXIMATELY 1/16 TH OF AN INCH.
I'm not sure what you may mean by "Steel Tracking". I'm going to assume you mean the steel belts and if they are visible , that is always bad. Any tire showing steel should be removed immediately.
1/16th of an inch is also 2/32nds which is the legal limit in many states and the accepted standard as the wearout point throughout the world of tires. Any tire showing 2/32nds anywhere on the tire - center or shoulder - should be removed from service.
3) IS IT TYPICAL THAT A TIRE IN THIS CONDITION WOULD RUN RISK OF TREAD SEPARATION?
Yes. In fact I would say a tire in that condition runs a HIGH risk of separation.
4) THE SEPARATION IN THIS TIRE WAS IN THE AREA OF THE PLUGGINGS.
This would confirm that plug type of repairs are unacceptable. In court, I would testify that the plug was the cause of failure.
5) IT YOUR OPINION THAT THIS TIRE WAS RUN UNDERINFLATED?
Yes. The fact that there are 4 repairs, means 4 times the tire was punctured.
6) WOULD TEMPERATURE OF THE PAVEMENT OR SPEED OF THE VEHICLE CONTRIBUTE TO THE SEPARATION?
Yes. The higher the ambient temperature, the more likely the tire is to separated. The higher the speed, the more likely the tire is to separate.
This is true of both repaired and unrepaired tires - except that the repaired tire starts off at a much higher risk level.
If you don't mind my asking, what's the story behind this question?
