This is a personal injury case in which a car windshield was smashed and the driver injured by a tire that "came off" a truck that the car was following on a high-speed interstate highway. The car driver was hospitalized and the car towed. The truck had one of its rear tires replaced and then departed the scene of the accident.
Tire & Rim Information:
A truck wheel consists of a pneumatic tire mounted and inflated on a steel rim. The rim is joined to the vehicle axles by lugs nuts that fasten to bolts.
- A radial truck tire inflated to the Tire & Rim Association Handbook recommended ambient temperature inflation pressure would not come off the rim or over-heat in normal highway service.
- The load carrying capacity of a correctly sized and mounted tire depends on its ambient temperature, or "cold", inflation pressure.
- Overloaded or Under-inflated tires generate excessive heat due to the increased deflection, bending, flexing and compression of the tire rubber.
- Overheating deteriorates the rubber material properties such as strength, adhesion, cut resistance, and tear resistance, which can lead to tire delamination or component separation failures. These types of failures usually occur in the thicker tread-belt area of the tire.
Tire Information from Appendix 1 Documents:
- The deposition, ref 2 - page 23, states there were 6 tires on the V1 Hino 268 truck, two tires on the front single axle and four tires on the rear dual axle. Ref 6 photograph confirms this statement.
- The State Police report, C020-2014-00384A dated 5/23/2014, ref 1, established that the left rear tire of V1 Hino 268 truck struck the V2 Dodge car. No inspection of the tire that struck V2 Car or the steel wheel rim on the V1 truck was reported. There were no comments concerning potholes or debris on the highway. The Police Report stated that the V1 truck departed the scene without assistance, after replacing the truck's tire with a new tire provided by a Tire Service Company, Ref 4.
- The Tire Services Companies Road Service Call Book Notes and Invoice B-166834 dated 5/23/2014, Ref 4, establishes that a new wheel lug nut, a metal valve stem, and one 11R22.5 Ironman I-208 Radial Medium Truck tire was mounted on the LRI, Left Rear Inside, wheel position on the V1 Hino truck at the scene of the accident. The Tire Services Company, Invoice also charged a "Tire Disposal Fee".
- The Tire Services Companies Road Service Invoice C25372 dated 5/28/2014, Ref 5, documents the replacement of both tires at the right rear inside and outside positions on the V1 Hino truck.
Expert Witness Opinion:
Excessive heat build-up in the rear radial V1 Hino truck tire caused by running the tire under-inflated, at highway speeds, caused the steel belt and tread to separate together from the tire carcass.
- The detached steel belts and tread struck the truck body causing a "Loud Boom" type noise and then struck the trailing V2 Dodge car.
- It is extremely unlikely that the thicker, heaver, steel radial truck tire would "Blow Out" like a passenger tire. Air loss just prior to the accident would not have allowed enough time for the tire to deflate, overheat, and delaminate.
- The tire was running under-inflated and the resulting tire over-heating was a pre-existing condition that lead to tread-belt separation from the tire carcass.
- The tire did not detach from the wheel's rim. The Tire Service Company road service invoice B-166834 dated 5/23/2014, Ref 4, charged a "Tire Disposal Fee" for removing and disposing of the tire. This fee supports the opinion that the tire carcass and bead remained on the wheel rim at the time of the accident and only the tread-belt flew-off due to heat separation and the centripetal force of the spinning tire.
- This type of radial truck tire tread-belt heat delamination due to under-inflation is a common occurrence and pieces of delaminated radial truck tread-belts are often seen on our highways and are known as "alligators".
- The tires at rear, inside truck axle positions are difficult to visually inspect and they are even more difficult to reach for inflation checks and for tire inflating.
- Experienced truck drivers are aware of this common truck rear tire under-inflation delamination problem and pay special attention to the inflation and any loss of inflation pressure for tires located at rear inside positions. Only calibrated truck tire air-pressure gauges give accurate tire inflation readings and other methods, like visual inspection or thumping a tire, are inadequate.
- The Tire Service Company, ref 5, replaced both right rear tires, RRO & RRI, on the V1 Hino truck only a few days after the accident occurred. This indicates that a proper tire inspection before the accident could have revealed a problem with the tire at the LRI position and prevented the failure.
This case is still in process and judgment has not been rendered.
Leighton Spadone, President of DAAS Inc., has over 50 years of Tire Technology and Applied Statistics experience. He trains and consults tire companies on Tire Design, Tire Materials and Compound Formulations, Tire Curing, rubber processing, quality control, tire, compound, and materials testing. Mr. Spadone was employed by Goodyear Tire & Rubber Co in International Technical Service and Domestic Tire Development for over 43 years and by Eurotire Inc for 6 years as the Chief Technical Officer. he is an experienced Materials Product Developer for Radial Light Truck Tires, Radial Medium Truck Tires, Farm Tires, and Off-Road Radial Earthmover Tires.
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