Stooge, Your rear axle could be askew. Make sure it's perpendicular to the center line of your bike. Believe it or not some people have a tendency to lean slightly when they ride and compensate with the steering. Tape a level across the top bars of your frame and check it out. Lastly, 290 lbs may be squishing your rear tire a bit. Try increasing the pressure. Ogy
All good tips..
THEN ya have the dreaded, just not in there square.. adjusted slightly right or left ya know? :shrug: That is about the most common, SUPER EASY to do, tire wear you can get.. You'd almost have to run a strait line down both lips of your rim, a known to be dead true wheel, aim the strait line through the length of the frame, to get it all PERFECT..
But that will increase the life of your tires ten fold, if it's adjusted exactly perfect.. Good luck with all of that though.. :laugh:
One VERY easy way to check alignment when it all looks right, is ask yourself if it would run no handed..?? If it feels like it would go in a strait line forever no handed, and no leaning and stuff.. It's about as close as it's going to get.. Any fight or pull in the ride AT ALL is chewing up tires..
SO then, if you're riding on pavement, soft DB tires.. All those factors factor in, multiplied by (rear wheel askew) and they burn up pretty fast..