In the 16" arena there is also the G rated tire with it's max inflation of around 120 psi, but I don't think my steel wheels are rated for them.... that and I'm not sure living in the desert that they would be prone to lasting any longer due to the environment. Back in June I left town to race in vegas. The road temp was 168 degrees. Stopped about 1/2 way for a snack break and my tire temps were 159. you can literally spend days reading info and stories on this subject. This was one bit of helpful info I found years ago at Discount Tires web site:

Trailer Tire Applications
•Trailer tires are designed for use on trailer axle positions only. They are not built to handle the loads applied to, or the traction required by, drive or steering axles.

Inflation
•Always inflate trailer tires to the maximum inflation indicated on the sidewall.
•Check inflation when the tires are cool and have not been exposed to the sun.
•If the tires are hot to the touch from operation, add three psi to the max inflation.
•Underinflation is the number one cause of trailer tire failure.

Load Carrying Capacity
•All tires must be identical in size for the tires to properly manage the weight of the trailer.
•The combined capacity of the tires must equal or exceed the Gross Vehicle Weight (GVW) of the axle.
•The combined capacity of all of the tires should exceed the loaded trailer weight by 20 percent.
•If the actual weight is not available, use the trailer GVW. If a tire fails on a tandem axle trailer, you should replace both tires on that side. The remaining tire is likely to have been subjected to excessive loading.
•If the tires are replaced with tires of larger diameter, the tongue height may need to be adjusted to maintain proper weight distribution.

Speed
•All "ST" tires have a maximum speed rating of 65 mph.
•As heat builds up, the tire's structure starts to disintegrate and weaken.
•The load carrying capacity gradually decreases as the heat and stresses generated by higher speed increases.

Time
•Time and the elements weaken a trailer tire.
•In approximately three years, roughly one-third of the tire's strength is gone.
•Three to five years is the projected life of a normal trailer tire.
•It is suggested that trailer tires be replaced after three to four years of service regardless of tread depth or tire appearance.

Mileage
•Trailer tires are not designed to wear out.
•The life of a trailer tire is limited by time and duty cycles.
•The mileage expectation of a trailer tire is 5,000 to 12,000 miles




One of the more "enlightening" things I noted was the "time" information, the "heat", and the general statement about pretty much not going by "tread wear".