The key indicator here is "less than 500 miles" and it wore the tires out. You could almost literally see the rubber coming off them at the rate. I really would check alignment and then get the pressure right. They don't need the 60# max but that shouldn't have worn them out that quickly. Could simply be the HF tires but I would still take the time to check the alignment with your experience in hand. Did the HF tires have a Load Range on them? Wondering if they were for highway use?
Here's an example for some trailer tires I have on a travel trailer. Website: http://www.maxxis.com/Industrial/Traile ... Chart.aspx
Click the red link to the PDF. Notice the Load Range is indicated and variation in load and pressure. This is a regulatory requirement that tires for highway use have these load ranges specified on them.
I have a Trailex trailer that carries two PAs side by side. The tires that came on it are 4.80-8 Load Range B
. This means a max air pressure of 60 psi which gets you 590 lbs capacity per tire. The Trailex trailer, per regulatory requirements, has a sticker on it specifying inflation pressure at 25 psi.
This means they were in no way planning for the trailer to weigh 1180 pounds. I do not have the Load Range chart for the tires and since it carries two PAs, I put 35 to 40 pounds in them. I have several hundred miles on them and they look like new. I carry a spare and remember putting 45 psi in it. The Trailex comes with a very nice axle and I made sure it was perpendicular to the axis of the trailer (i.e. alignment) when I assembled it. I did not fret over toe in/out because the axle appears to be outstanding quality as expected as part of the big price you pay for a Trailex.
Are the new Carlisles highway rated (i.e. Load Range B)?