Geez, I didn't know that player pianos used rubber friction drive
parts.  These wretched items are, of course, a specialty of consumer
audio equipment, with which I dealt for many years.

The best old source was the Projector-Recorder Belt Company, of
Whitewater, Wisconsin, and many a belt and wheel did Kinsler Hi-Fi
Service buy from them.  They became PRB, then something else, and now,
combined with the other belt company EVG, they're at

  http://www.russellind.com/

which is important because they _used_ to make and restore old idler
wheels and also build custom belts for weird machines.  I don't know if
they still do that.  Player piano stuff may be a bit on the large size
for them, but perhaps not.  Anyway, their catalogs are there, and you
can perhaps find something that'll fit.

Mark Kinsler
Lancaster, Ohio, USA
http://www.mkinsler.com/
http://howthingsoughtawork.blogspot.com/

 [ http://www.russellind.com/prbline/index.html
 [ http://www.russellind.com/EVG/main.htm
 [ -- Robbie