I’ve read through the speed dialer hum discussions, but am still in the dark as to how to treat the issue.
some say that the trailing edges should be sharpened, others say they should be dulled.
worked for some, not for others.
i’ve also experienced a strange problem where, at a certain speed (usually just after dropping in or after pumping several times and moving fast) i feel a strong slowdown almost as if the brakes have been thrown on. After reading about fin turbulance created at speeds, i thought that it may be related to the issue of humming.
Rear edges should be sharpened not dulled. Flat spots on the rear edge (usually close to the surface of the board) are the culprit 99% of the time. Can also be a nick or chunk taken out of the fin somewhere. Inspect them closely for flat spots or any nicks or burs. Run your fingers over them. Imagine that they are the water passing over the surface of the fin. Feel anything weird or anything other than a smooth "zip" off the back of the fin..check that area. Flat side fins should be sharpened/foiled towards the flat side. Centers should have equal amount taken off both sides meeting in the center.