Grand piano truck question

[Travis Gordy]

Situation:  College where I service pianos. S&S D on truck.  Student
performance.  When he began playing, the piano moved a small amount but
enough to cause the student to move the bench closer. No movement after
that. The two men that had rolled the piano into position told the
department head they had set the wheel breaks.  I was in the audience and
do not recall them doing so. One said that the wheels could not have rolled
but twisted, and that where he was previously employed the piano trucks had
softer rubber tires that gripped the floor better and prevented twisting. 
Can anyone tell me if his claim is valid and/or make comments about this
situation.

I do not live in the town where the college is.  The dept. head called the
day after the performance and asked if I could get softer wheels.  He could
not find the name of the truck or wheel manufacturer on the truck. I have
not been back to check things out.  At my suggestion that he lock the
wheels and play the piano himself to see if he could make it move he said
he could not for a while because it was in its garage and drama dept.
occupied the area.  I said I would ask the guys and gals on the net for
information to which he said, "Great". So, thank you in advance for your
response.

Regards to all,  Travis Gordy

BTW, the PTG Regional at Wichita a few weeks ago was great.  Could expect
nothing less from the high powered talent for instructors.  As always I
learned some very useful things.  Saw some of you there.