Coopers should be available local to you. Discount tire and a lot of independents carry them. I've sworn by them for 20+ years. Only tire I have not had a blow up or otherwise with. My son has some on his pickup, 20-30K miles with a 60K mileage warranty, you can hardly tell they are worn.
On the other hand, a van I drive for work has the Firestone HT on it. I have 20+K miles and they also look hardly worn. Maybe the OEM version is not as hard, or long lasting rubber as the in store version.
Marty
92 Navistar dump truck, 7.3L 7 sp, 4.33 gears with a Detroit no spin
2014 Chevy 1500 Dual cab 4x4
92 Red-e-haul 12K equipment trailer