Tires 15,000 mile test @60 mph & 40 psi

[Q45tech]

"b. Michelin's Long-term Durability Endurance test

The second accelerated aging method being considered by the agency is based on a method utilized by Michelin. This method uses a road wheel endurance test with the following controlled parameters to simulate testing the tire to tread wear-out: load, inflation pressure, speed, and duration. The test tire is inflated with a 50/50 blend of O2/N2 and run for between 250 - 350 hours. Michelin has estimated that 100 hours of this testing correlates with approximately one year of real-world tire usage. For example, a 250-hour test correlates with approximately 2 ½ years of real world field operation.The Michelin long-term durability endurance test research findings were initially published at a 1985 International Rubber Conference. (40) The research pointed toward four factors as comprising the best balance to achieve good/accurate correlation with field data - 1) filling gas; 2) test speed; 3) test temperature; and 4) tire load. Michelin discovered that if any one or several of these factors was disproportionately altered in an attempt to make the test more stringent or to complete the test faster, the result was a test failure condition that displayed an abnormal failure mode and did not reflect actual field conditions. Therefore, temperature and mechanical stress must be controlled to avoid failures that are not representative of real-world conditions.

The following test parameter values have been developed, through a multi-year research program at Michelin, to minimize variance from field test end conditions and minimize test hours:Filling gas blend: 50 percent O2 (oxygen) and 50 percent N2 (nitrogen)Test speed: 97 km/h (60 mph)Test temperature: 38C (100F)Load: 111 percent for standard load P-metric tires; 112 percent, 98 percent and 92 percent for LT tires load range C, D, and E, respectively.Inflation pressure: 40 psi (275 kPa) for standard load P-metric tires; 57, 65, and 80 psi (390, 450, 550 kPa) for LT tires load range C, D, and E, respectively.

Test duration: 250 hours.

These values were chosen to make each test parameter proportionally severe without exceeding a critical temperature which, in turn, would lead to failure conditions unrepresentative of real-world conditions/ actual field conditions.

A tire complies with the proposed requirements if, at the end of the test, there is no visual evidence of tread, sidewall, ply, cord, inner liner, or bead separation, chunking, broken cords, cracking, or open splices, and the tire pressure is not less than the initial test pressure."http://www.nhtsa.dot.gov/cars/...reIII

More scarey stuff:http://www.nhtsa.dot.gov/cars/...ecV_B

[maxnix]

Great links which require thorough reading.

I thought one of the most obvious charts was the Estimated Annual Average Number (1995-98 NASS) and Rates of Blowouts or Flat Tires Causing Tow-away Crashes. Here, the percentage of tire failures involved in rollover accident for cars vs. non-rollovers is about 6+ times greater. However, the same statistic for light trucks is about 20+ times greater! All hail the riser kits.

Just because one can go 90 mph in an SUV certainly doesn't mean one should!

[911/Q45]

If only we could ensure that they don't contribute to the gene pool before they go........