How could you tell it's a masterlock? They come in packs of two for about 4 bucks. No one can steal the rear wheel unless they notice the key on the handlebar stem.
Even though it's still 100 outside, I took the Silver Flyer out for a ride. After 3 miles, the rear tire failed, it didn't blow out, just has a big deformity in it, so it rubbed the frame. Back home, I was putting on some $3 kendas when the chain grabbed the brass plate next to the sprocket and bent it before I noticed what was happening. So it went up on a bike hook until I get to it this weekend.