I have a grand piano with an extremely heavy/stiff action. Is it possible to lighten the action without completely rebuilding it? Is this something a professional piano tuner would do or would I have to find someone else with this specific skill/training?
(In case it matters, this is an old 5'8" Kimball Viennese Classic)

I am aware of the importance of good posture, fingering, using arm weight properly, etc., but I'm just learning so my skill is low and it's difficult to improve when I can't practice more than 15-20 minutes at a time due to fatigue.

  • 1
    Related: music.stackexchange.com/questions/64065/…
    – Tim H
    Commented Feb 3, 2018 at 11:57
  • Thanks for link - my searching didn't turn up that one (although I remember seeing a similar discussion of using arm weight etc in a different topic - definitely something I need to focus on)
    – S. Burt
    Commented Feb 4, 2018 at 17:28

2 Answers 2


You say it's heavy/stiff. Which? If the action is well-regulated, there's probably little that can be easily done about the weight. But a piano technician can do something about 'stiff'. We can't diagnose this online. Call your tuner in to advise.

  • I guess I don't know what the difference is between heavy and stiff (lack of experience, sorry). It takes significantly more force (compared to other pianos I've used) to push the keys down.
    – S. Burt
    Commented Feb 3, 2018 at 0:54
  • My advice stands.
    – Laurence
    Commented Feb 3, 2018 at 1:07

Yes, a stiff piano action can be lightened. Possible causes for the resistance can come from:

  • an unbalanced key;
  • deteriorated or misadjusted pivot felts.

To start with, you could try making your feeling objective by measuring the minimal weight that initiates the motion of the keys. I don't remember the normal values but that can be found online, or you can compare with other pianos.

If the required weight is larger than normal, this may be adjusted by changing / picking or even adding oil in the pivot joints. But this should not done randomly, by guess! A standard regulation procedure should be applied. In some extreme cases, weight can be added in the key itself---as in this picture, but with weights on the other side of the key support).

A professional should be able to tell you easily. If, for some reasons, you want to avoid calling a tuner, you might want to try evaluating if friction in the pivot joints is too high. For example, by disassembling the hammer and counting the number of oscillations when dropped from ... (see standard procedures).


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