I have replaced wheels on big old upright player pianos on several
occasions.  I have a foldable upright tilter which is very portable.
I'm 47 years old and weigh about 150 pounds.  With this tool I can
easily flip big old uprights onto their backs all by myself.  If you
want to be able to move the piano more than a foot or so, on a regular
basis, I recommend using double-wheel ball-bearing casters and get
the harder rubber (polyurethane) type, not the soft rubber -- the
weight of a big old upright player would "smush" (flatten and destroy)
the soft rubber.

The sockets that come with the new casters are smaller than the holes
originally bored for the steel wheels.  You would likely have to buy
the wooden bushings that compensate for the smaller diameter sockets
with these newer casters.  There should be no play between the socket
and the hole it goes into -- it should be a tight fit.

Benners Farm in Setauket, Long Island, told me they wanted their nice
English Weber player piano to be more portable so that they could roll
it out onto the porch outside and all over the large barn that hosts
many community events for various groups.  Busses full of kids are
constantly pulling in and out during the day.  The kids parents love
their experience and the player piano is one of the highlights.  Like
player pianos, real farms with lots of livestock and crops are quite
a novelty in this land of urban sprawl and high property taxes that
make profitable farming extremely difficult.  Kudos to Benners Farms
for all their success.

I have installed these wheels on player pianos in senior homes, where
I have been told that music is one of the greatest therapies to help
victims of Alzheimers and dementia.  Now, with the new wheels, the
player piano can be much more easily moved where it needs to be to
provide therapy.  I know that replacing wheels on player pianos can
often make a positive difference in peoples lives.

Bill Maguire

 [ See, for example, http://www.schaffpiano.com/catalog/casters.pdf 
 [ -- Robbie