Post
by seahouse » Wed Oct 07, 2015 9:13 pm
Yipes, sipes!
There are a lot of things wrong with that tire, I would not attempt any highway run with it (it is unsafe, but you already knew that) and if it is 5 or more years old (check the date code, it likely is) I would replace it/ them soon, unless you plan on just a few short and slow trips.
Rotating them might get rid of the humming (well, maybe not right away) and even out the wear a bit (but not the inside wear, of course) as a temporary stop-gap measure, but note that your contact patch will be smaller until it wears in (which will take longer than you want to have the tire on for, LOL).
I see cracking at the base of the tread (it has had a hard life), feathering (severe) all across the tread blocks, as well as the uneven inside wear that is probably the main source of your question. Are these things present all around the circumference of the tire? Maybe a belt has slipped in the tire? Tire balance is out, a weight has been thrown off?
You might want to run a slightly higher pressure in them, there is a bit less wear at the centre than the edges. (This is one of the best indicators you can have for determining ideal inflation pressure, the evenness of wear across the tread width). A tire is at its maximum load bearing capacity at its maximum inflation pressure, which will be written on the sidewall, and you could be close to it. On a car I tweak mine according to that feedback at every rotation (every 6 months or so, when the winters go on/ off) to get it even, and find the manufacturers recommendation is usually spot on.
Since you have checked and ruled out the bearings and have zero toe (though some toe-in is desirable) that leaves negative camber, as mentioned, as one culprit. Excessive play in the torsion bar pivot (“suspension”) could be a point to check as well. Or possibly a bent axel? Check the brakes? Fasteners in the trailer?
Unfortunately there is not much, if any ability to adjust camber and toe-in on the trailer. So there is not a lot you can do about them other than replace (maybe rotate) the tires. Note that with some tires some feathering is normal. (I don't believe I have ever seen a used motorcycle tire that did not have some feathering, it's part of the design).
Also on some (performance) cars negative camber improves performance, handling and responsiveness. If the car is driven as it was intended, wear will be even, but if it is not, then wear on the inside of the tires, just like on your trailer, could be considered to be “normal”.
Well, you pretty much got the answer I think you were expecting but might not have wanted to hear... new tires are in the near future. Good luck!
, the torsion bushings on the axle sleeve r being overloaded so adding a second axle with brakes will up-grade ur trl load capacity to I believe # 7500 
