Case 580SK, 12 ply rating, 19.5L 24 rear tires. Bought rear tires new some years ago. YKS, made in Thailand. Outer rubber started cracking around the second or third year. Not heavily used. I originally aired them according to the manual, which states 24 psi. I just found another place in the manual that states 8 pr:20psi, 10 pr:24 psi. Since mine are 12PR I increased pressure to 28psi. I cannot find recommended pressure info anywhere on the tire, and cannot find the tire on any website. Does 28psi seem reasonable? Also, could low pressure have contributed to the cracking?
Those cracks are not from pressure.
Looks like old rubber to me
Yep, just Asian rubber, nothing you can do about it except buy better tires.
I thought maybe low pressure causing over flexing.
Was going to buy new, but the ones I wanted are $950 each, and I was buying them more for the tread, which would have kept chains on the lugs, instead of falling between the lugs like on the current tires. Since these hold air just fine I'll stick with them for now.
If you are that worried, throw some tubes in there and call it a day. I wouldn’t buy new tires unless I had to.
The main reason for new tires was for a tread with lugs that run at about a 45° angle to the plane of rotation and would thereby support chains in the winter, without the chains falling between the lugs.