I made  cab isolators out of   sidewall  18.4x38's   using  a  3 inch hole saw..  After burning  about   10 'pucks'  out..filling the shop with smoke.. and almost killing my drill press,   I  took a  3 inch pipe,  sharpened the end and used the shop press to  cookie cut  the  rubber.   I'd bet  just about anything could be  sharpened to make a little bigger  'tire' for the sweep.
  LOL,   amazing the uses  for old tires!