The "secret handshake" is finding VALID information on which to base your research and repairs....
As an example (and I'm not picking on you), just using YOUR posted information to highlight some examples of "good and bad" information. As I post your links, I'll try to explain why it's "good or bad"...
First, in post #6, you posted a link to a Trailer King tire inflation/load chart:
https://fifthwheelst.com/documents/T...lation2014.pdf
That chart is dated Jan 21, 2014. It is a "composite chart" and EVERY tire size is listed with a "combined load range" that's built in that tire size. As an example, the ST225/75R15 lists "inflation pressures/capacity" for load range B, C, D and E tires. THAT IS 1 TIRE SIZE IN 4 DIFFERENT LOAD RANGES. In reality, that is 4 different tires, all listed on one line of a chart. It is NOT one tire used in 4 different applications.
The chart depicts four different tires, all the same 225 mm of tread width, built with load range ratings of 4ply (LRB), 6ply (LRC), 8ply (LRD) and 10ply (LRE). That chart depicts the carrying capacity for each of those tires, it is NOT a chart that allows you to "pick and choose" the best pressure to run a 10 ply tire being used in a 4 ply application.... Also note the outdated speed rating of 65 MPH.
There is also a disclaimer: "FOR ST TRAILER TIRES USED IN NORMAL HIGHWAY SERVICE" with no explanation of what that disclaimer means.... Is a fifth wheel "normal highway service" for that tire??? Or is a fifth wheel a "special service application" ??? You'd have to go back to the 2014 Trailer King criteria to find out....
Then, in post #2, you listed a link to a more current TK tire load/inflation chart:
https://www.towmaxtires.com/tire/details/towmax-str-ii
In that chart, EACH TIRE SIZE AND PLY RATING are separately listed. In this chart, THERE IS NO LOAD/PRESSURE APPLICATION TO LOWER THE PRESSURE FROM THE LOAD RATING FOR A 10 PLY TIRE AND USE IT AS A 8 PLY TIRE.... What TK has done in this chart, is eliminate what you see in the 2014 (outdated) chart. I'd say the reason they changed the chart configuration is to eliminate the "misconception" that you can simply "air down a LRE tire to 50PSI because the "chart says" that size tire at 50PSI can carry a reduced load.... The current TK charts DO NOT allow reduced air pressure on any load range tire to "accommodate less pressure/less load capacity"....
If you look at the current TK chart that you linked, in the 14", 15 and 16" tire sizes/load range ratings, each tire is a line entry with a specific TK tire model and a single, specified load range, pressure requirement and carrying capacity. Gone is the "pick and choose your pressure" in the older charts.
Look at the charts, compare what "they used to allow as a misconception" and how they "eliminated that potential with the new chart configuration"...
My point is, with the new charts, there is no application where you'll find a 235/80R16 LRE tire where there's a pressure/load capacity rating for 50PSI or 65PSI. TK eliminated any chance for an owner to "think the chart says I can air down my tires"....
NOWHERE in the current TK inflation chart will you find a load range for a 235/80R16 LRE tire that gives you a tire capacity if you run that tire at 65PSI...
I'm not intending to confuse you (hope I haven't) and I'm not trying to belittle you or your research. I'm just trying to use your information that you provided, to highlight how both of those documents "contradict" each other, in how the information is presented and how it's intended to be interpreted.
Your tires, on your trailer (according to the manufacturer's data, found on the decal you posted) are intended to be 235/80R16 LRE tires, run at 80PSI. Your tires are MAX24T* and that is the ONLY line in the current chart that you can use to inflate YOUR MAX24T* tires. None of the other lines apply to that specific model/size Trailer King Tire.
Now, as to the question of whether the axle assemblies are the right ones, the tires are the wrong ones or the trailer GVW is incorrectly stated.... I'll leave that to be determined by Keystone's engineering/safety compliance experts....
But, your tires, according to that placard, do not permit you to "safely deflate your tires to 70 PSI to smooth the ride"... The current TK tire load/inflation chart also doesn't even list a load range for your tire when inflated to 50 or 65 or 70 PSI.
I hope this makes some sense to you... All the manufacturers are "tightening the interpretation of charts" by eliminating their "old shortcuts to make the chart easy to read" because, in many situations, the charts left too much for people to "wrongly interpret".... These two charts, well, the 2014 version, is a perfect example of how that could happen.... I'd guess that Trailer King never intended for people to use that chart to "interpret that it's OK to run a LRE tire at 50 PSI and use it at that pressure as a replacement for a LRC tire.... But that's what the chart "implied". The current chart eliminates that misconception by listing each tire by size/model/pressure/load capacity as an individual line item. You can't use the other lines for other tires to apply to your tire model.
Hope this is more than "clear as mud"....