Bent rim, incorrect tire pressure, bike overloaded, swing arm not aligned properly, Tire is mounted backwards, Your 16 year old son is doing burn outs when your not home. Take your pick
Its the tire that came with the bike. Notice it just this past riding season. I just got back into riding with this bike after not riding for 25 years.
Maybe if you feed it more it will not eat your tires. Center wear is usually Over inflation. Did you check your clearance between your tire and fender?