I was told that if a grand piano is to be located on a concrete or tile-on-concrete floor that something should be put under the casters so that strong vibrations that are conducted down through the legs are not reflected back up from the floor.
Is there any truth in this?
I was thinking that the only way that these reflected waves can cause damage in the long-term is if they resonate sufficiently strongly at specific frequencies within the piano to cause micro-damage at glue joints and cause delamination over the long term.
My soon-to-arrive Sauter Omega 220 has big, locking double-casters (picture below) and I've never come across caster cups that would be large enough to go under them. In any case I don't want to use caster cups because I may have to move the piano very occasionally (e.g., when I tweak the piano's position). It also means that I can't (and don't want to) put the piano on a large rug because it makes it difficult to roll the piano and then reposition the rug under the casters after that.
I used Magiglide sliders
under the casters of my Kawai K-8, and they worked very well. I moved that piano around a lot in my effort to find the best location for it in my living room. I could use the larger Magiglides (in pairs) under the casters of the Omega, but I'd like to avoid them if possible because they just aren't all that visually appealing.