Check belt tension sonic meter method?

[CruiseRT]

Sonic meter is a device that measures sound, so I thought I would have a go at it to see what I could come up with. BRP uses the Gates 507C Sonic meter, so I read the manual and they explain everything you need. Take a look, I might not have explained what I did very well but it seems quite simple given BRP gives you all the numbers except the measured frequency. These numbers are from a 2013 RT Service manual.



According to Service manual for 2013 RT:

Belt tension is 1050N +-150N and
Mass 8.4 g/m
Width 28.0 mm/R
Span 1028 mm

I recorded the frequency of my belt with an old Sansa MP3 player. I just recorded the belt as I strummed it like a guitar string.
I opened the sound recording in a program called Kwave, A Linux program for analyzing sound waves:I use a Linux operating system, but you should be able to find a Windows program to do the same thing.

Then I measured the wave cycle time where the sonic meter takes its measurement (Actually measured about 12 cycles and averaged them) The wave below is expanded out so you can see the pattern.

Then I converted the time to a frequency.
Frequency in Hz.=1/time in seconds
Now just plug all the numbers into the formula provided by Gates.
T=4 x M x W x S[SUP]2[/SUP] x f[SUP]2[/SUP] x 1e10[SUP]-9[/SUP]

M = Mass = 8.4 g/m
W = Width = 28.0 mm/R
S = Span = 1028 mm
f = Frequency = 27.4
(x 10-9 Just move decimal 9 places to the left)
746.42= 4 x 8.4 x 28.0 x 1056784 x 750.76 x 1e10[SUP]-9[/SUP]

Since everything is constant except the frequency you could simplify

T=0.9942223872 x f[SUP]2[/SUP]

T=746.42 Newtons

746.42 Newtons = 167.8 lbs.

My Krikit checks it at 175 to 180.

What do you think, could this be useful?

 

[jthornton]

Pretty slick and best of all your using a Linux computer. I use Linux whenever I can, 5 out of 7 computers in my shop run Linux and LinuxCNC.

JT

 

[CruiseRT]

been using Linux fo about 7 or 8 years. It has everything you need and is free.

 

[billybovine]

Is there an app for that.

I have been thinking about this topic for a couple days since it was brought up again. I did a search for meters to see if there was one available at a deep discount price for a tool that I may use once a year. Looking at the meters available I started thinking all they are is a microphone attached to a smart device with software that calculates a value. Well my smartphone has a microphone and has lots of computing power, is there an app for that? Well Blackberry world does not have one but the number of apps for it is limited, only 100,000 or so. So I was wondering is there an app for this in the Android or the I world? If not, could someone write one? Realise I don't know what is involved in writing an app.

 

[CruiseRT]

I have been thinking about this topic for a couple days since it was brought up again. I did a search for meters to see if there was one available at a deep discount price for a tool that I may use once a year. Looking at the meters available I started thinking all they are is a microphone attached to a smart device with software that calculates a value. Well my smartphone has a microphone and has lots of computing power, is there an app for that? Well Blackberry world does not have one but the number of apps for it is limited, only 100,000 or so. So I was wondering is there an app for this in the Android or the I world? If not, could someone write one? Realise I don't know what is involved in writing an app.

Not sure about an app maybe try google play. Linux is free and will run on just about any computer, most distros will run from cd or a usb stick, you don't even have to install.

 

[jthornton]

been using Linux fo about 7 or 8 years. It has everything you need and is free.

Well not everything, It won't run my CAD or CAM programs so I have to use Windoze for them. And no they won't run with WINE. The other thing I've not found is a good small business accounting software for Ubuntu...

JT

 

[Yol Bolsun]

I have been thinking about this topic for a couple days since it was brought up again. I did a search for meters to see if there was one available at a deep discount price for a tool that I may use once a year. Looking at the meters available I started thinking all they are is a microphone attached to a smart device with software that calculates a value. Well my smartphone has a microphone and has lots of computing power, is there an app for that? Well Blackberry world does not have one but the number of apps for it is limited, only 100,000 or so. So I was wondering is there an app for this in the Android or the I world? If not, could someone write one? Realise I don't know what is involved in writing an app.

Did I hear App? opcorn:

Oops, App Info is over on a different thread. Thanks Doc - Riverside!

 

[Ben Burped]

I listened to a "tech" at my dealer tell me all the reasons he could tell that a customer had been adjusting their own drive belt and all the many reasons they had to not honor the warranty, so I bit the bullet and bought the Gates sonic meter. It's not worth crap. The majority of the time I tap the belt it doesn't display anything. I talked to Gates and they blamed the problem on my settings and wouldn't issue a return authorization. Pay a "tech" to do this and let there be an official record that it was adjusted properly.

 

[Dan McNally]

I listened to a "tech" at my dealer tell me all the reasons he could tell that a customer had been adjusting their own drive belt and all the many reasons they had to not honor the warranty, so I bit the bullet and bought the Gates sonic meter. It's not worth crap. The majority of the time I tap the belt it doesn't display anything. I talked to Gates and they blamed the problem on my settings and wouldn't issue a return authorization. Pay a "tech" to do this and let there be an official record that it was adjusted properly.

How could a tech tell if someone adjusted their own belt? Is he psychic? Did the customer use a monkey wrench to do it?

 

[pidjones]

Dredging up an old thread, because Gates does have an app for that - Carbon Drive (at least on Android - on the Play store). Needs a very quiet area to perform it and sometimes shows 2x the primary frequency, but on my '21 RT works as well and more repeatable than the Krikit (and it's free). A quick ballpark formula of .994 x frequency squared = force in Newtons or .22304 x frequency squared = force in pounds will get you close enough since the app doesn't display in fractions of Hz. Change the OPs formula if your belt length, etc. is different.

So, no need for a Krikit or expensive belt frequency meter if you just have a smart phone. And mine is an old LG from 2016 running Android 7. I'm sure there is an iPhone app that matches on the Apple store.

 

[ButterSmooth]

Dredging up an old thread, because Gates does have an app for that - Carbon Drive (at least on Android - on the Play store). Needs a very quiet area to perform it and sometimes shows 2x the primary frequency, but on my '21 RT works as well and more repeatable than the Krikit (and it's free). A quick ballpark formula of .994 x frequency squared = force in Newtons or .22304 x frequency squared = force in pounds will get you close enough since the app doesn't display in fractions of Hz. Change the OPs formula if your belt length, etc. is different.

So, no need for a Krikit or expensive belt frequency meter if you just have a smart phone. And mine is an old LG from 2016 running Android 7. I'm sure there is an iPhone app that matches on the Apple store.

I 'tested' my Android phone and it is insensitive to sounds below about 60 Hz, so doesn't hear in the range required to measure belt tension. That 2x (first harmonic) pops up since it is in the audio range of the phone.

I use a Snark musical instrument tuner that 'hears' or 'feels' the belt vibrations very accurately. I tested first with a high quality recorder and used Audacity to measure the frequency. The Snark (I paid $11,way back when) results were in perfect agreement with the more expensive and cumbersome method. The sonic method is much more sensitive to change and is more repeatable than the Krikit. Using the sonic method, I 'trained' myself how to correctly use the Krikit, and after some effort, the two readings to agreed. The Krikit requires more skill to produce accurate/repeatable results, but I'm not sure we need that much accuracy, since the lack of vibration while riding is the proof in the pudding. It does help if the readings are repeatable.

The only way I could get the Krikit to agree with the sonic method was to use it on the bottom span of the belt, where I could accurately center and align it and then push on it very squarely.

 

[Rednaxs60]

There is one for the iPhone. Downloaded it.

 

[ButterSmooth]

There is one for the iPhone. Downloaded it.

Check the frequency response before you go too far. It needs to work down around 30Hz. My Motorola Android would only go down to about 60Hz. I tested with a tuba...

 

[Rednaxs60]

Check the frequency response before you go too far. It needs to work down around 30Hz. My Motorola Android would only go down to about 60Hz. I tested with a tuba...

Have a ways to go before using if I do. Have been looking into a KriKit or equivalent as well.

 

[bluewoo]

My s21 did a good job reading 33 hz with this app. I'm not really good with formulas could you show an example to calculate the actual lbs?

 

[ButterSmooth]

.22304 x frequency squared = force in pounds

So, 33 X 33 = 1089 (frequency squared)
1089 X .22304 = 242.89#

 

[bluewoo]

.22304 x frequency squared = force in pounds

So, 33 X 33 = 1089 (frequency squared)
1089 X .22304 = 242.89#

Thanks, math is not my strong point!
So my belt is very tight at 243 lbs!

 

[ButterSmooth]

Thanks, math is not my strong point!
So my belt is very tight at 243 lbs!

Specification (wheel off the ground) range is 202 – 270, so you are in the mid-range. If that measurement is on the ground, it's probably about 20# higher than off the ground, so ~223#. Mine seems to work best at 235# on the ground, 210# wheel off the ground. Different bikes and different people doing the measurements get different results. If you don't have belt vibration issues, I wouldn't screw with it -- avoid the headache.

Also, be aware that there are 'tight' and 'loose' spots caused by rear pulley eccentricity. I measure both spots and take the average.

 

[bluewoo]

Specification (wheel off the ground) range is 202 – 270, so you are in the mid-range. If that measurement is on the ground, it's probably about 20# higher than off the ground, so ~223#. Mine seems to work best at 235# on the ground, 210# wheel off the ground. Different bikes and different people doing the measurements get different results. If you don't have belt vibration issues, I wouldn't screw with it -- avoid the headache.

Also, be aware that there are 'tight' and 'loose' spots caused by rear pulley eccentricity. I measure both spots and take the average.

(checked on the ground)
Luckily with my knee surgery I wont be messing with it for a while. I only had just 500 + miles before the dealership replaced the engine so now I'm finding a couple of boo boos on the dealers part of loose ground wire and body panel not installed correctly. Its not even broken in so pretty useless to adj the belt at this time anyways until I put some real miles on it.

Thanks for all the good advice and information!

 

[Doug44]

(checked on the ground)
Luckily with my knee surgery I wont be messing with it for a while. I only had just 500 + miles before the dealership replaced the engine so now I'm finding a couple of boo boos on the dealers part of loose ground wire and body panel not installed correctly. Its not even broken in so pretty useless to adj the belt at this time anyways until I put some real miles on it.

Thanks for all the good advice and information!

Oh my, my, new engine on a 2021 with 500 mi. I do believe if that was my Spyder it would be the dealerships again. ����