2004 Mazda Mazda3 Q&A
2004 Mazda Mazda3 Question: Rear tires wearing out on the inside of tires.
The alignment is causing the uneven wear. If the tires are splayed outwards(negative toe value), they will scrub the inner edges as you drive. This will also happen if the vehicle has been lowered, causing the tires to tilt inwards riding on the inner edge of the tire. I recommend replacing the tires and having an alignment performed. - XDealerTechs
Allignment issue probably - Felix Dube