It's nothing about drums or axles. It's about whether backing plates are interchangeable between 7.25 with 10 x 2.5 and 8.75 with 10 x 2.5 inch brakes. Think you just answered my question. The 7.25 is only 4 bolt. Never knew if 7.25 even came with 10 x 2.5 inch brakes.