My heart goes out to you bordercollie ~~~ nothing more aggrivating to have to purchase things twice, so close together !!
All I've ever had other than the OEM atv's, is the 589's..... So really don't have nothing to compare to . Both of them are 6 ply, Including the mudlites..... That being said, and both the 589's and mudlites are coming from ITP .
I can say this, I would first contact the manufactor, and go from there. Myself, have had NO problems with the 589's at all, but I've really only run mine in the winter months, and don't have near the working hours that you have. A very close friend of mine has 589's on three of his RTV's, two Rangers, and two Rhinos that stay in the construction business. And so far, he has had no complants.
But, let me say this, if one has to, and ITP don't stand behind their tire like they should, might just have to get the gut-buster Essex tires, they are tuff !!! Let us know how the ITP company treats you, I'm very concered with it !!!!
~~~~~~~~~ jamie
TWO GUNS SWAMPS OF LOUISIANA