Waynes World - June 2009
ROADCHECK 2009 SET FOR EARLY JUNE,
RETREAD TIRE FACTS, AND...
NEW STUDY SUPPORTS
RETREAD SAFETY
by Wayne Schooling
"ROADCHECK 2009" SET FOR EARLY JUNE
The annual roadside inspection blitz known as “Roadcheck” is scheduled for June 2-4, 2009, throughout the U.S., Canada and Mexico. Conducted by the Commercial Vehicle Safety Alliance (CVSA), Roadcheck is the largest targeted enforcement program on commercial vehicles in the world. On the average, approximately 14 trucks or buses get inspected every minute from Canada to Mexico during the 72-hour period.
During the 2008 event, 24% of vehicles were placed out of service, which was the lowest vehicle out-of-service rate recorded in the 21-year history of the event. Just over 5% of drivers were placed out-of-service, a 14% improvement over 2007. More than 8,500 CVSA-certified inspectors, at 1,850 locations across North America, perform the Roadcheck truck and bus inspections.
NEW STUDY SUPPORTS RETREAD SAFETY
The public perception is that retreaded tires are less safe than new tires and are responsible for most tire scraps found on the sides of U.S. highways. A recent government study aims to change that perception.
As part of the National Highway Traffic Safety Administration’s Commercial Medium Tire Debris Study, researchers collected and studied hundred of discarded truck tires and casings and over 1,000 tire fragments from five sites in the U.S. They concluded that the proportion of tire debris from retread tires and new tires is similar, when based on estimated proportion of retread and new tires in service for heavy and medium-duty trucks.
“Indeed, the new tire versus retreaded tire proportions of the collected tire debris broadly correlated with accepted industry expectation,” the study reports. “Additionally, there was no evidence to suggest that the proportion of tire fragments or shreds from retreaded tires was overrepresented in the debris items collected.”
The results came as no surprise to the Tire Retread & Repair Information Bureau, an industry association. The study “should prove once and for all that the true cause of tire debris on our highways is not because of retreads,” the group stated. The study supports a long-standing argument from the retread industry that retreads are just as safe as new tires, and that tire failures occur mostly due to a lack of tire maintenance or through road hazards.
Researchers collected more than 86,000 tons of tire/rubber casings and debris for the study. Tire forensic experts then examined a random sample of 300 discarded tire casings collected from truck stops and about 1,200 tire fragments collected along the interstate highway system to determine: 1) Probable tire failure type; 2) Probable axle location of the failed tire; and 3) The most likely reason for the tire failure.
When examining the tire fragments and tire casings, where the new tire or retread status was actually known, researchers found that road hazards were the most common cause of tire failure, at 38% for new tires and 36% for retreads. Maintenance and operational issues accounted for 32% of the failures, while under-inflation accounted for 16%. Analysis of the tire fragments also found that excessive heat was evident in 30% of the samples collected and examined.
“These results suggest that the majority of tire debris found on the nation’s highways is not a result of manufacturing or process deficiencies,” the study states. Researchers did note that “maintaining the correct tire air pressure is the key to optimal performance, safety, and durability.”
An evaluation of crash data revealed that vehicle crashes related to truck tire failures and truck tire debris are rare events that account for less than 1% of traffic crash involvements. A significant proportion of the casings examined (108) were likely to be from trailers, the study says, while 65 were likely to be from the drive axle, and 61 could not be identified as to axle service.
“This general result was anticipated,” researchers concluded. “In practice, many fleets tend to run first-retread casings on the drive axle and then concentrate retread usage on the trailers.” When looking at available crash data, researchers found the following: 1) the data showed much higher incidence of tire defects in truck crashes on roads with posted speed limits of 60 mph and above. The incidence of tire defects was particularly high on roads posted at 75 mph; 2) tire-defect-related crashes are about twice as likely to be single-vehicle crashes and to involve loss of control than other truck crashes; 3) rollover itself was much more likely in crashes in which the truck had tire defects than in other types of crashes; and 4) tire failure on tractor steering axles is associated with vehicle loss of control. In every case examined in detail, when the tire failed, the truck swerved toward the side where the failure occurred.
RETREAD FACTS
Fact: it takes about 22 gallons of oil to make one new truck tire, but just 7 gallons for a retread. Fact: tires can be retreaded an average of 3-4 times; Fact: retread tires are used primarily for the cost advantage they provide over a similar new tire. Fact: if a retreaded tire is well maintained, it can have the same or better durability, performance, and longevity of a new tire.
THE WAY TO CREATE AMILLION-MILE TIRE
1) Place a new tire on the drive axle of a twin-screw tractor in line-haul operation. Miles = 600,000. 2) Then, put the tire on a trailer for two years. Miles = 660,000. 3) Buff and put another drive tread on it, at a tread depth of about 26/32”. After this first retread, put the casing back on the drive axle for another 300,000 miles. Miles = 960,000. 4) Then, return the tire to a trailer axle when the tread depth is about 8/32”. Run it for another 40,000 miles. Total miles = 1,000,000! Do this for all of the tires on your truck, and you will save a load of cash every year.
~ NTA remains a name you can trust. Our website (www.ntassoc.com) is your official U.S. DOT Internet Training Site and we are administrators of a Nationally Accredited Drug and Alcohol Program. If you have any questions, call me at (562) 279-0557 or send me an e-mail to wayne@ntassoc.com. Until next month, “Drive Safe – Drive Smart!”