The National Highway Traffic Safety Administration's (NHTSA) proposed tire testing standards "do not correlate with real world experiences," officials from the Tire Association of North America/International Tire & Rubber Association (TANA/ITRA) said in a letter sent to the agency this afternoon.
"Most tire-related accidents are caused by under-inflation, road hazards, improper tread depth and other user-related factors," according to TANA/ITRA -- not by flaws in tire design and construction, as NHTSA suggests.
"TANA and ITRA believe that it is the consumer's responsibility to use and maintain their tires properly, and while NHTSA's proposed changes to tire testing are a preventative step toward safer tires, it is the resolution of consumer error, not revised tire construction, that will make the greatest impact on United States roads and highways."
TANA/ITRA commented on several tire test proposals by NHTSA:
1. High-speed tests. TANA/ITRA supports the Rubber Manufacturers Association's (RMA) call for a speed test that produces running temperatures 21% higher than current standards rather than NHTSA's proposed speed tests, which would run tires first at 87 mph, then 93 mph and, finally, 97 mph. "Any present-day tire with a Q rating is not designed to pass (NHTSA's) last test," say TANA/ITRA officials.
2. Endurance tests. NHTSA's proposal to test tires for longer periods of time at progressively heavier loads while running under-inflated are do not reflect real world conditions, according to the association. "While testing Load Range E tires at 75 mph might be acceptable, to test them for 10 hours at 100% load and 22 hours at 110% load on a test wheel at 56 psi is not realistic when the tire is designed to run at 80 psi."
3. Low inflation pressure tests. TANA/ITRA opposed NHTSA's suggested low pressure inflation tests that would test all tires at 30% below placard or 20 psi, whichever is greater -- levels that are "far off the recommended psi of almost any passenger or light truck tire.
"Tires must be run at specific recommended pressure to perform safely."
4. Road hazard impact tests. "It is impossible to design a tire that can withstand all road hazards," say TANA/ITRA officials, who claim NHTSA has not properly defined "the problem for which they are proposing a test." In addition, retreads should be exempt from road hazard tests, according to TANA/ITRA, as "the retread process does not affect the structure of an original casing."
TANA/ITRA also demands that retreaders be exempt from proposed bead unseating tests, which could cause "significant economic impact on small retreading facilities."
TANA/ITRA officials also commented on other topics like shearography, the effects of aging on tires and NHTSA proposals regarding specialty radial and bias-ply tires.
"Every test must be based on sound science and have a proven track record for improving safety."
The costs of NHTSA's proposals, which will extend far beyond the agency's original estimates, "do not outweigh the speculative, unproven benefits."
