WASHINGTON (Jan. 16, 2009) — New and retreaded medium truck tires have pretty much the same failure rates and modes, according to a tire road debris study performed for the National Highway Traffic Safety Administration (NHTSA) by the University of Michigan Transportation Research Institute.
Tire forensic scientists in the study examined 300 casings from truck stops and 1,196 tire fragments culled from highway locations in Virginia, Florida, Indiana, Michigan and Arizona. They found that road hazards, maintenance/operational factors and overdeflected operation were the reasons 76 percent of the casings were taken out of service, with few manufacturing deficiencies evident, the study concluded.
While 68 percent of the tire fragments were from retread tires, this did not indicate that retread tires performed worse on the road than new tires, the study said.
“The OE vs. retread proportions of the collected tire debris broadly correlated with accepted industry expectations,” it stated. “Additionally, there was no evidence to suggest that the proportion of tire fragments/shreds from retread tires was overrepresented in the debris items collected.”
Of the 728 fragments for which scientists could determine the failure cause, road hazards and excessive heat were the culprits in more than two-thirds of the blowouts.
“These results suggest that the majority of tire debris found on the nation's highways is not a result of manufacturing/process deficiencies,” the study concluded.
It also said that less than 1 percent of truck crashes across the U.S. can be attributed to tire failure.
The study's authors suggested topics for further research, such as a longitudinal study of a truck tire's life cycle and a separate study on wide-base truck tires.