Our Carriage 5er was built with 7 k dexter axles with 12" x2" brakes, E range tires.
Braking was poor, tire wear terrible. Springs and morryde equalizers ok.
Swapped the axles after 2 years for 8k dexters with 12/1/4" x 3 3/8 drums with forward self adjusting brakes , tires to. G range china Long March, run at 90 psi 10 years since, 40k miles.
tire wear was good, braking much better.
At 10 years old, last year we replaced them with another recommended china G rated tire. Samson. Hieavy load high pressure rated tires run at lighter load with pressure lower than rating seems like the answer for us.
The 7k axles and Duro E tires I used to build a dump bed, Those OEM Duro E tires all failed on the dump bed trailer with cord separation within 3 years
Upgrading the axles and tires was the right thing to do for us.