ButterSmooth
New member
Since it's snowing and I can't ride, revisiting the belt tension filled the day. When I swapped the rear wheel, I used the Krikit II to tension the belt. My Krikit II has always disagreed with the harmonically measured tension, so I wasn't totally satisfied that the tension was correct.
My plan was to find and use another frequency measuring device as a confirmation or rejection of the Snark tuner I've been using. First up was the Carbon Drive app from gates. Second was Spectrum, another frequency measuring app. These are both cell phone apps and I discovered that my cell phone audio input system has a frequency floor of 52 Hz, so these were of no value in measuring the belt.
Next candidate was a Zoom H4n audio recorder and Audacity. It was easy to record nice clean samples of the belt twang with the Zoom. I couldn't find a way to view the spectral plots in Audacity when focusing on the frequency range that relates to the belt. I stretched out the signals (they were quite 'clean') and used the period of the zero crossings to calculate the frequency.
Using the formula and belt specs provided by Gates and calculating the tension, the result was 101# (22.3 Hz). The Krikit measured 165# - 175#. My Krikit technique, while repeatable, must be quite bad, or my particular Krikit has a problem. The good news is the Zoom/Audacity method is in near perfect agreement with the Snark tuner, which is much easier to use. I've also validated the accuracy of the Snark with a known frequency generator (in this case a tuba).
Since Can-Am uses the harmonic method in the manual, it is my method of choice. The rub is that everyone else is using the Krikit. The common number of 160# is a Krikit number and may not transfer to the harmonic measurement method – which leaves me on my own.
Previously when the adjustment seemed correct (no vibrations), the Snark method indicated 180# on the ground, so that's where I'll begin. The tension increases ~20# between air and ground, which is ½ step on the Snark(A# → B).
The other 'quick and dirty' method used by seasoned Harley riders is to grab the belt in the middle of span and try to twist it as far as possible. 90° twist is about right, less is too tight, and more is too loose. My belt twists ~110° which agrees with the 101# measurement. At 180# it's almost a perfect 90°. It's a good on-the-road quick check.
This was a snow-day exercise and in general I prefer the 1st principle of Aawen, Ride More, Worry Less.
As a final note on tension my four readings were:
122# in the air at the loose spot
150# on the ground at the loose spot
173# in the air at the tight spot
193# on the ground at the tight spot
for an average tension of ~160#
on the ground at the tight spot with the Krikit 205#->215#
My plan was to find and use another frequency measuring device as a confirmation or rejection of the Snark tuner I've been using. First up was the Carbon Drive app from gates. Second was Spectrum, another frequency measuring app. These are both cell phone apps and I discovered that my cell phone audio input system has a frequency floor of 52 Hz, so these were of no value in measuring the belt.
Next candidate was a Zoom H4n audio recorder and Audacity. It was easy to record nice clean samples of the belt twang with the Zoom. I couldn't find a way to view the spectral plots in Audacity when focusing on the frequency range that relates to the belt. I stretched out the signals (they were quite 'clean') and used the period of the zero crossings to calculate the frequency.
Using the formula and belt specs provided by Gates and calculating the tension, the result was 101# (22.3 Hz). The Krikit measured 165# - 175#. My Krikit technique, while repeatable, must be quite bad, or my particular Krikit has a problem. The good news is the Zoom/Audacity method is in near perfect agreement with the Snark tuner, which is much easier to use. I've also validated the accuracy of the Snark with a known frequency generator (in this case a tuba).
Since Can-Am uses the harmonic method in the manual, it is my method of choice. The rub is that everyone else is using the Krikit. The common number of 160# is a Krikit number and may not transfer to the harmonic measurement method – which leaves me on my own.
Previously when the adjustment seemed correct (no vibrations), the Snark method indicated 180# on the ground, so that's where I'll begin. The tension increases ~20# between air and ground, which is ½ step on the Snark(A# → B).
The other 'quick and dirty' method used by seasoned Harley riders is to grab the belt in the middle of span and try to twist it as far as possible. 90° twist is about right, less is too tight, and more is too loose. My belt twists ~110° which agrees with the 101# measurement. At 180# it's almost a perfect 90°. It's a good on-the-road quick check.
This was a snow-day exercise and in general I prefer the 1st principle of Aawen, Ride More, Worry Less.
As a final note on tension my four readings were:
122# in the air at the loose spot
150# on the ground at the loose spot
173# in the air at the tight spot
193# on the ground at the tight spot
for an average tension of ~160#
on the ground at the tight spot with the Krikit 205#->215#
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