Edit and addition to my previous post:
My take on the testing and certification process… keep in mind any tire company has the liberty to build a better tire if they choose to do so, and IMHO is why one name stands out above the rest of the ST tire builders when recommendations are asked for on the forums…
Following the standards and testing procedures isn’t light reading nor is it any fun to try to decipher what they say and mean… I am not a expert and make no claims to be but when I tried to follow the testing procedures here is what I have come up with… it isn’t all inclusive in so much as it doesn’t cover ambient temps and resting times between test and possibly there are some other test done I am not even aware of, and it has been many years since I went through all of this…
Here is the short version of the testing they go through for that all important DOT certification…
All testing for the ST tire is done at maximum tire air pressure…
2-hour test: 88% of tire maximum load rating at 50 MPH
30-minute test: 88% of tire maximum load rating at 75 MPH
30-minute test: 88% of tire maximum load rating at 80 MPH
30-minute test: 88% of tire maximum load rating at 85 MPH
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Now compare that to the testing for a LR E LT tire…
Category B Endurance Test:
(LT "E" tire at 50 PSI)
4-hour test: 85% of tire maximum load rating at 75 MPH
6-hour test: 90% of tire maximum load rating at 75 MPH
24-hour test: 100% of tire maximum load rating at 75 MPH
Low Inflation Endurance Test:
(LT "E" tire at 37.7 PSI)
90-minute test: 100% of maximum load rating at 75 MPH
High Speed Performance Test
(LT "E" tire at 60 PSI)
30 minute test: 85% of maximum load rating at 87 MPH,
30 minute test: 85% of maximum load rating at 93 MPH,
30 minute test: 85% of maximum load rating at 99 MPH
Note the all test for the ST were at full PSI and none of the test for the LT were…
The problem is the trailer industry loves them because they can buy them cheap…
The tire mfg. love them because they can build and sell them cheap…
Buyers love them because they can buy them cheap…
Tire and trailer industries ensure there is little interchangeability for light weight trailers (under 10,000 pounds) to keep you buying them…
NHTSA has little incentive to raise the standards because they get few complaints and a lot of pressure from mfg.’s not to make changes…
Tread separation is a tire problem not a ST tire problem… it is seldom caused by road hazard and mostly by an internal deficiency in the materials used or the build processes…
Corrosion of the steel belts, old or improper adhesives, contamination of adhesives during the build process, lack of protective gum strips at the belts edge, no protective cap, misplacement of belts, all aid in or cause tread separation…
Very often it is caused by poor quality materials and application of the inner liners themselves…
ST tire issues and country of origin tire issues are separate issues but very much connected today… so much so it is now hard to separate them from one another…
While there are some on here that attempt to defend Chinese mfg. there is no doubt all of these problems are huge in Chinese tire mfg. plants… example Kumho has had many problems and recalls from their china operations but not from their other sources that I am aware of…
With the ST tire, I believe the problem of Chinese mfg. is magnified many times over because almost all of them are mfg. under a no-name off brand and private label companies with very little control of either material, or build quality, and the multi-level subcontracting, cheating in testing, and little to no accountability… even major companies with a physical presents there fight these same quality issues every day… importers of private label tires can never be sure one shipment will be like the last or the next, but they are cheap….
