How many hours of travel does it take to wear out LEGO monorail tires?
I went to Brickcon 2012. I asked Joe Meno about his red Monorail and he was most helpful. He flipped it over to expose the undercarridge and he was able to show me LEGO tires with fifteen hours of running time. The tread does indeed wear off and the tires actualy begin to split. The rubber doesn't cling to the rails themselves, but residue does begin to accumulate below the tracks. The ease of clearing the area of the tire debrie all depends on what you have built below the track. It can be blown clear, or wiped away.   These two sizes of tires were used to run Joes train.    ...The tread on the driven tire is beginning to wear down.  ...and you can see the non-powered wheel has begun to separate.