need tire advice

Mile High wrote:

snip

RV manufacturers are only going by the numbers given to them- just like Joe Bloe does when he buys a tire on his own. He looks up the size and he looks up the capacity. If there is a hidden formula that the RV manufacturer is supposed to use to safeguard against poor quality tires, why is that not the tire manufacturers responsibility to disclose that. RV manufacturers aren't building cars, not even close, and car manufactureres aren't buying ST tires, so not sure where you were going with that. I could never blame the RV manufacturer for ordering a LRE rated for 3,500 lbs to put on a 7,000 lb axle. I would!

There is no secret formula for how much you can exceed the load/inflation/speed limits. The regulations are clear. All tires certified to pass the tests are supposed to be able to do so. No one has ever said tire x must be 10% better or 2% better. That is not the law.
I bring up the car companies as they all have engineering staff with the specific task of selecting tires based on historical performance. Part of their decision process involves their knowledge on the expected use by the expected customers of their product. They also know the variability of their product (vehicle).
The RV industry to my knowledge does not have a single engineer on staff with the responsibility of specifying tires that address any of the special needs of modern RVs or of the variations observed in today's RVs. They ignore the documented load imbalance they design into their vehicles and many times it is this imbalance that results in tire overload.
I do believe the manufacturers know that they need to improve the quality of their product but I also believe that much like Detroit in the '70's they choose short term profit over long term quality for the owners of their product.
Some have chosen to select tires that are not at the limit of their design. LT tires allow higher speed but at a lower load capability.

The ST tire regulations were written when the speed limit was 55 mph with towing at 50. The LT regulations were updated just a few years ago.

Asking that somehow the lower priced ST tires be expected to operate at their +20% load as well as at higher speeds is asking that the laws of physics be changed.

I believe that if you were to limit your speed to 50 mph max 100% of the time and to always to run the inflation on the tire sidewall 100% of the time and ensure that no individual tire was ever overloaded even 1% of the time and run TPMS, you would probably get 5 years out of your ST tires.