I bought my 05 LX back in August 05 and currently have 4500km (Ottawa Canada). In the last 2 months, I also noticed a rubber smell on the right rear tire area. No unusual tire wear. Seems to only happen when it's wet out. Dragging rear brakes would not put out a smell like that. Interesting theory on the exhaust coating from ibike. If I come up with something I'll share with everyone.