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Hey everyone, just want to let you know I came across a great guitar tuner app for Android phone operating system. The app is called gStrings. Great interface, you just open the app, and press "Tune auto". Ideal tension on my 748 is 110hz. Let me know if anyone else finds this app helpful.

Greatest thing: it's Free! The app is free, and you don't need to buy any fancy guitar tuning microphone or computer software. You just use the mic on your phone. Very portable and easy to use!

 

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Nice find. My only concern is how much variability there is in the density between belts. I know from playing guitar, I prefer certain strings over others based upon density (e.g. 11's vs. 9's or 10's). The thicker heavier strings give me a little bit more string tension versus a lighter gauge when tuned to the same note (i.e. resonate at the same frequency). It's a great idea if we find that the frequency is consistent across different belts on different bikes.

Either way, nice to see people thinking outside the box!
 

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Nice find. My only concern is how much variability there is in the density between belts. I know from playing guitar, I prefer certain strings over others based upon density (e.g. 11's vs. 9's or 10's). The thicker heavier strings give me a little bit more string tension versus a lighter gauge when tuned to the same note (i.e. resonate at the same frequency). It's a great idea if we find that the frequency is consistent across different belts on different bikes.

Either way, nice to see people thinking outside the box!
Apparently, the bike list includes:
Streetfighter, 1198, 1098, 1098R 999, 998, 996, 916, 848, 749, M1100, MS4, MS4R, MS4RS, ST4, SC, ST3, ST2, SS1000
HYM 1100, MTS 1100,MTS 1000, MS2R 1000, M696, MS2R 800, M620, M400, M695, SS800, MTS 620

So this method should apply to all superbike riders. Many people have been using the guitar tuning style to tension their timing belts. 1/2 turn is also a good (but less exact) way to check tension.
 

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Using the Gates 604 you have to enter belt mass for each application. Assuming this, you will not be accurate with the guitar tuning method.

BTW it's 110 Hz for new belts only and I believe 85 Hz for used belts.
 

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I'm interested in hearing people's thoughts on this. I was planning on doing a similar sound check on the belt tension using an iphone app.

anyone compared methods to see if it's reproducible and reliable?

Chris
 

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Mayor of Simpleton
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???

You don't need the mass to measure frequency.

Set to 110 Hz for new belts. Done.

I can't verify, but I assume that 85 Hz figure is the correct spec when checking after they are broken in.
 

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Discussion Starter #8
I believe 85hz is correct for used belts, but who installs used belts on their bike? I guess if you're just checking for fun it would be fine, but once you install new belts at the right tension it would probably be best to leave them alone when they break in.

Any other android or iphone users have other apps to share for using this method?
 

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???

You don't need the mass to measure frequency.

Set to 110 Hz for new belts. Done.

I can't verify, but I assume that 85 Hz figure is the correct spec when checking after they are broken in.
Just telling you all a fact. When using the Gates (OEM manufacturer of Ducati timing belts) Hz frequency type belt tension meter you must enter the measured belt mass for each belt type and style you measure.
 

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And I'm just telling you a fact. Some tool may ask for other data. It can ask what you had for breakfast, but Hz is Hz.

If I'm doing 70mph in a 5000 pound SUV or 70 mph in a 1800 pound Volkswagen, it's still 70mph and the same ticket in the eyes of the cop.

Now the damage I'm going to do if I collide with something in each of those scenarios...
 

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Sonic Tension Meter Operating Theory
When an impulse is applied to a belt span, it first oscillates in all modes of
vibration, but the higher frequency
modes decay faster
than the fundamental mode.
This leaves a continuous sinusoidal
wave that is related to
a specific belt tension; note
diagram.
Using a microcomputer, a
data processing method to
capture a belt's natural oscillation
frequency was
developed. Using this
method, the wave form frequency
can be determined
easily.
The new system uses special sensors to detect belt oscillation wave forms.
Data from these sensors is sent to the microcomputer inside the Sonic
Tension Meter for processing and conversion into the natural frequency. To
calculate belt tension, the Sonic Tension Meter system uses the “transverse
vibration of strings theory.” To operate the meter, the belt mass, span
length and width of the belt must be entered.
Formula:
T = 4 x M x W x S2 x f 2 x 10-9
Where:
T = Belt span tension (Newtons)
M = Belt mass constant (gf/m/mm)
W = Belt width (mm) or number of belt strands
S = Length of the span to be measured (mm)
f = Natural frequency of the belt (Hz)
Unlike a string, belts have cross-sectional rigidity. Therefore, tension values
measured by the meter may be higher than the actual belt tension,
depending on the operating conditions under which the effects of rigidity
arise. When the actual belt tension must be more precisely measured, a
simple calibration test may be necessary.
 

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Wow! it got real quiet in here!:D
 

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Mayor of Simpleton
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You don't need to calculate belt tension if you have a frequency--the whole point is that's already accounted for in the SPEC--in this case 110 Hz. And whether belts are Bucci, Gates, or whatever else, they are recommended for this specific application and either exact matches (dimensions) or close enough (chemical/structural makeup) in their properties that at 110 Hz, all will exhibit nearly the exact same tension--and well within the safe and optimum operating limits set by Ducati.
 

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Nine16 has it all wrong. He, very incorrectly, (no disrespect intended) misunderstands what we're trying to measure here, and how that measurement is (indirectly made) and what we really care about [ducat has it just right]

First, the belt mass ABSOLUTELY matters. I'll try to explain.

What we are REALLY trying to set here is belt tension. Quite contrary to what Nine16 says, we could really give a hoot about frequency.

But, there's no easy and cheap method (and in cases of restricted access, no method at all) to measure that tension. So, we fall back on the resonant frequency as a proxy for tension. Again, frequency in and of itself, doesn't measure tension, which is what we're really trying to get at. But, frequency is proportional to tension, AND MASS. i.e. if you gave this to a half clever high school student, they'd quickly show you, that the frequency would track tension, but that for every different mass, the relationship between the frequency and tension would be different. Therefore, not knowing the mass, means not really knowing the tension either.

Again, ducat, has this just right, as did the tool developer (and anyone else that did more than stumble through high-school physics) ;)

Where Nine16 is right-ish, is that the frequency won't, for a given belt length and tooth count, vary much, simply because the mass won't very much. But if we're going to crudely go for 'just good enough' then no frequency measurement is needed to begin with, because most people can get it by feel and twist anyway.

How accurate to you want to be.

Again, not trying to beat up Nine16, just trying to provide some clarification as to how stuff works. His end-result (approx correct tension) is probably achieved, but his explanation of mass not mattering was way off.
 

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Mayor of Simpleton
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I have no misunderstanding and I never said mass didn't matter. I said it was unnecessary. It is irrelevant for the purposes of getting the frequencies. Any belt you chose is essentially going to be the same--which makes mass a CONSTANT in those equations. If it will help you sleep at night, you can re-measure the span every time too. Never know when those case-mounted pulleys are going to change positions on you. Got to make sure, right?

When I buy a chicken from the grocer, I don't ask what it weighed with the head and feathers. There is no reason for 99% of Ducati owners to care what the actual raw tension figure is if you have a simpler measurement that is directly proportional. The other "variables" are statistically insignificant.

But by all means, show us. If the Gates belt is 5 grams heavier than the Bucci, crunch the numbers and tell us how we should only set a Gates belt to 109 Hz and the Bucci to 110.
 

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Surely Frequency has been pre-determined by taking the belt Mass into account, for a specific belt, by Ducati. So why do we need to know what the mass, for example, of a 916 belt. All 916 belts have the same mass and therefore require the same frequency. It has been pre-established by the Ducati Gods:).

In my mind Nine16 your High School Physics is bang on in terms of practical application. Of course I could be out of Tune:)
 

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Chilehead
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I have no misunderstanding and I never said mass didn't matter. I said it was unnecessary. It is irrelevant for the purposes of getting the frequencies. Any belt you chose is essentially going to be the same--which makes mass a CONSTANT in those equations. If it will help you sleep at night, you can re-measure the span every time too. Never know when those case-mounted pulleys are going to change positions on you. Got to make sure, right?

When I buy a chicken from the grocer, I don't ask what it weighed with the head and feathers. There is no reason for 99% of Ducati owners to care what the actual raw tension figure is if you have a simpler measurement that is directly proportional. The other "variables" are statistically insignificant.

But by all means, show us. If the Gates belt is 5 grams heavier than the Bucci, crunch the numbers and tell us how we should only set a Gates belt to 109 Hz and the Bucci to 110.
+1.

Tom
 

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Great find! Love me some Android phones! Thanks for sharing this!
 

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What setting the belt mass and width will do is give you a conversion for how many foot pounds of tension is applied to the belt. Some require at least one value to initiate and give a reading. It will read the HZ frequency regardless of what belt is being read. At least that is what I understand from my email to gates. I will be using a free program call ispectrom and an external mic on my MacBookPro. I have a nice quiet garage so back ground noise will not be a problem. Now if I could find a killer deal on a real instrument I would be all over it. 500 too 600 is a bit much. Set it with the mic and give it a twist for common sense and your done.
 

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Surely Frequency has been pre-determined by taking the belt Mass into account, for a specific belt, by Ducati. So why do we need to know what the mass, for example, of a 916 belt. All 916 belts have the same mass and therefore require the same frequency. It has been pre-established by the Ducati Gods:).

In my mind Nine16 your High School Physics is bang on in terms of practical application. Of course I could be out of Tune:)
Since it's become a topic of discussion, my high school physics was AP, followed by the (#2 ranked) College of Engineering at the University of Illinois Champaign-Urbana.

JDuc, Turboflyer and anyone else interested, a friend and I used an iPhone when we serviced my bike this spring. It was very easy and a laptop would work just as well.
 
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