Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 04-18-15, 03:39 PM   #1
mooder
Senior Member
Thread Starter
 
Join Date: Jul 2014
Bikes:
Posts: 224
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Spoke pitch frequency

Hello all,

I came across this:
Bicycling - Wheelbuilding: check spoke tension using musical pitch

Quote:
If the tension of the two laced spokes is approximately the same, as it should be, you will hear a single, clear musical note. In a typical 700C three-cross wheel, this should be an G with plain-gauge spokes and an A with butted spokes.
Using the android app G strings (yea bad pun with G standing for guitar) most spokes of a front wheel I trued are around 100Hz. Some dip in the 50-60 ish and some in the 200 (too tight).

What does G & A stand for in frequency? G = 98Hz? A = 110Hz?

For my front wheel, what would be the correct frequency per spoke (R500 - 10 spokes each sides)?
mooder is offline   Reply With Quote
Old 04-18-15, 04:45 PM   #2
Willbird
Senior Member
 
Willbird's Avatar
 
Join Date: Jun 2014
Location: Very N and Very W Ohio Williams Co.
Bikes: 2001 Trek Multitrack 7200, 2104 Fuji Sportif 1.5
Posts: 2,458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
There is an iPhone ap that will relate the pitch right back to a tension, but you need to enter the spoke gauge, the crossing spoke must be damped too, I was not really confident in the results :-).

id say buy a park tension meter , I got one to build a wheel , and just used today it because I had a few loose spokes on my Sportiff, a disk brake front wheel (you did not specify if yours is or is not ) might have different tension on the two sides just like a rear wheel does.
Willbird is offline   Reply With Quote
Old 04-18-15, 04:59 PM   #3
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 35,437
Mentioned: 105 Post(s)
Tagged: 1 Thread(s)
Quoted: 3790 Post(s)
While matching pitch can be an effective way to compare spoke tensions within the same wheel, (or same flange) it's not reliable for measuring absolute tension since the pitch is a function of spoke gauge and free length along with tension.

There's no such thing as a "typical 700c 3x wheel", unless you limit yourself to ones having shallow depth rims, small flange hubs and 14g plain gauge spokes. Then there's the issue of the "right" tension for front, rear right side, and rear left side, and of course factor disc brakes, and rear axle width.

So sound is a useful tool, but like any other tool, requires some skill and understanding to be used correctly.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is online now   Reply With Quote
Old 04-18-15, 05:39 PM   #4
Andrew R Stewart 
Andrew R Stewart
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder
Posts: 8,834
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 830 Post(s)
My cousin, John S Allen, wrote a Bike World article about this method of spoke tension checking in something like 1981. But that was when spokes were round. Andy.
Andrew R Stewart is offline   Reply With Quote
Old 04-18-15, 07:05 PM   #5
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Bikes: Several, mostly not name brands.
Posts: 18,312
Mentioned: 44 Post(s)
Tagged: 0 Thread(s)
Quoted: 806 Post(s)
Spoke pitch is more useful in comparing relative tensions among spokes than in determining absolute tension of individual spokes.
JohnDThompson is offline   Reply With Quote
Old 04-18-15, 07:55 PM   #6
mooder
Senior Member
Thread Starter
 
Join Date: Jul 2014
Bikes:
Posts: 224
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
The thing is that the spoke tension meter made by park tool is like 90$
Surely a nice tool to have for those of us doing the maintenance ourselves but in the amazon comments many user were saying it was practically useless and they could do a good / faster job by pitching the spoke.
I am willing to spend the money on one but it's somewhat uber expensive for what it is (as always with park tools).
http://www.amazon.ca/Park-Tool-Spoke.../dp/B000OZDIGY
mooder is offline   Reply With Quote
Old 04-18-15, 08:11 PM   #7
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 35,437
Mentioned: 105 Post(s)
Tagged: 1 Thread(s)
Quoted: 3790 Post(s)
This is one of those "buy it if you want it" but you probably don't need it. It's a matter of deciding what your objectives are and considering alternatives.

I've been building wheels for nearly 50 years, and never bothered with tension measurement except by feel. I now use a tension aguge from time to time, just to cross check my fingers' calibration. So far it's usually only confirmed what I'd already guessed, though sometimes I'd find I was drifting low or high and use it as a guide to get back on track.

But I've never used a tension meter to achieve equal tension. That's done by sound and feel, which is far, far faster.

So if you simply want to compare spoke to spoke tension within the wheel, save your dough. But if you want to know the actual tension and have no frames of reference, then sound will get you into the ball park. I believe there are even smart phone aps that allow for various spoke combinations, and they should certainly get you pretty close.

But as I said, buy it if you want it.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is online now   Reply With Quote
Old 04-18-15, 09:12 PM   #8
Mark Kelly 
Senior Member
 
Mark Kelly's Avatar
 
Join Date: Oct 2009
Location: Willy, VIC
Bikes:
Posts: 644
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by FBinNY View Post
While matching pitch can be an effective way to compare spoke tensions within the same wheel, (or same flange) it's not reliable for measuring absolute tension since the pitch is a function of spoke gauge and free length along with tension.
The part that is often missed is that since maximal spoke tension is proportional to cross sectional area which corresponds to mass per unit length, you can replace the mass per unit length in the pitch equation with a constant, so pitch at maximal tension becomes

F1 = K.SQRT(T) / 2L

where T is spoke tension and L is spoke length.

Since there's less than 6% difference between common 700C spoke sizes there's less than a semitone of pitch variation amongst them at maximal tension.
Mark Kelly is offline   Reply With Quote
Old 04-18-15, 09:27 PM   #9
FBinNY 
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter
Posts: 35,437
Mentioned: 105 Post(s)
Tagged: 1 Thread(s)
Quoted: 3790 Post(s)
Quote:
Originally Posted by Mark Kelly View Post
The part that is often missed is that since maximal spoke tension is proportional to cross sectional area which corresponds to mass per unit length, you can replace the mass per unit length in the pitch equation with a constant, so pitch at maximal tension becomes

F1 = K.SQRT(T) / 2L

where T is spoke tension and L is spoke length.

Since there's less than 6% difference between common 700C spoke sizes there's less than a semitone of pitch variation amongst them at maximal tension.
You're right that the same pitch will translate to tension in proportion to spoke diameter. And many old timers including myself will factor diameter, in setting our target tensions, but most builders today don't, and try for the same tension range regardless of the spokes used. Moreover, old timers that do factor gauge tend also to factor rider weight and other variables, so there's no magic number or pitch, though there's room in the ballpark.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

“Never argue with an idiot. He will only bring you down to his level and beat you with experience.”, George Carlin

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is online now   Reply With Quote
Old 04-19-15, 02:09 AM   #10
dabac
Senior Member
 
Join Date: Mar 2008
Bikes:
Posts: 7,276
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 625 Post(s)
Kiu
Quote:
Originally Posted by mooder View Post
..in the amazon comments many user were saying it was practically useless and they could do a good / faster job by pitching the spoke.
Pitch is fast and fairly easy for comparing spoke to spoke, but it's a lot harder to use it to determine WHICH tension you're building to.
Likewise, w/o a tensiometer, it's hard to know how close in pitch you need to get it to be good enough.
I've never regretted buying one and use it frequently.
dabac is offline   Reply With Quote
Old 04-19-15, 03:03 AM   #11
trailangel
Senior Member
 
trailangel's Avatar
 
Join Date: Feb 2014
Location: Pasadena, CA
Bikes: Schwinn Varsity
Posts: 2,468
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 667 Post(s)
https://itunes.apple.com/us/app/spok...518870820?mt=8
I use that iphone app and I think it's excellent. What's the problem with it again?
trailangel is online now   Reply With Quote
Old 04-19-15, 09:18 AM   #12
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 8
Posts: 29,137
Mentioned: 66 Post(s)
Tagged: 0 Thread(s)
Quoted: 3194 Post(s)
Started playing Guitar in the 60s , Mandolin in the 70's, I just used my common sense, building wheels .. and had felt what most other finished wheels seemed like.
fietsbob is offline   Reply With Quote
Old 04-20-15, 07:39 AM   #13
davidad
Senior Member
 
Join Date: Feb 2009
Bikes:
Posts: 5,251
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 130 Post(s)
Quote:
Originally Posted by mooder View Post
The thing is that the spoke tension meter made by park tool is like 90$
Surely a nice tool to have for those of us doing the maintenance ourselves but in the amazon comments many user were saying it was practically useless and they could do a good / faster job by pitching the spoke.
I am willing to spend the money on one but it's somewhat uber expensive for what it is (as always with park tools).
http://www.amazon.ca/Park-Tool-Spoke.../dp/B000OZDIGY
I bought the Wheelsmith years ago when I started building my own and friends' wheels. It's great for ultimate tension and matching tension of the spokes. I don't do it for a living, so it is not an every day job.
If you don't think you will build many don't bother.
davidad is offline   Reply With Quote
Old 04-20-15, 10:10 AM   #14
Kopsis
Senior Member
 
Kopsis's Avatar
 
Join Date: Apr 2008
Location: St. Pete, Florida
Bikes:
Posts: 1,260
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Quote:
Originally Posted by mooder View Post
What does G & A stand for in frequency? G = 98Hz? A = 110Hz?
G and A are the names of the corresponding musical pitch (A, B, C, D, E, F, G). In this case the "A" is actually "A2" - a pitch two octaves below (1/4 frequency) A4 (also called A above middle C). A4 = 440Hz is the tuning standard that has been in use by the music industry for nearly the last century. But exactly how the other musical pitch names corresponds to a frequency is a surprisingly complex subject.
Kopsis is offline   Reply With Quote
Old 04-20-15, 12:20 PM   #15
peterws
Senior Member
 
peterws's Avatar
 
Join Date: Oct 2014
Location: Near Lancaster
Bikes: Carrera Virtuoso and friend
Posts: 305
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 46 Post(s)
I USE AN APPROXIMATION OF THIS METHOD IF I HAVE A SLIGHT BUCKLE ON THE RIM.Usually after hitting a bad rut or kerb. Slight damaghe to the straightness of the rim locally will need increased tension or decreased tension on the other side to pull it straight. The musical pitch will change. As long as it`s within certain limits, it`ll be fine.

To determine the limit, try pinging the spokes on the back wheel, gear side. There is tremendous tension there to compensate for lack of leverage. Any snapped spokes will occur here. And it`s a an absolute bugger to change `em . . .! Dunno why they don`t just put more spokes on that side . . . heck, I could do that myself . . .I`ve got 32 to play with . .
peterws is offline   Reply With Quote
Old 04-20-15, 12:36 PM   #16
noglider 
aka Tom Reingold
 
noglider's Avatar
 
Join Date: Jan 2009
Location: West Village, New York City
Bikes: too many
Posts: 31,704
Mentioned: 221 Post(s)
Tagged: 0 Thread(s)
Quoted: 2576 Post(s)
I don't use a tensiometer when building wheels, and I generally don't use pitch, either. I just use feel. My question is: how much pitch variation is OK? I got as much as a minor third (musically speaking) difference between the lowest pitch and the highest pitch I found in the wheel I built most recently.
__________________
Tom Reingold, [email protected]
New York City and High Falls, NY
Blogs: The Experienced Cyclist; noglider's ride blog

"Don’t buy upgrades. Ride up grades." -Eddy Merckx

Please email me rather than PM'ing me. Thanks.
noglider is offline   Reply With Quote
Old 04-20-15, 03:11 PM   #17
rms13
Senior Member
 
Join Date: Apr 2013
Location: Santa Clarita, CA
Bikes:
Posts: 6,249
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 140 Post(s)
interesting. I'm going to play around with my guitar tuner tonight!
rms13 is offline   Reply With Quote
Old 04-20-15, 03:16 PM   #18
Willbird
Senior Member
 
Willbird's Avatar
 
Join Date: Jun 2014
Location: Very N and Very W Ohio Williams Co.
Bikes: 2001 Trek Multitrack 7200, 2104 Fuji Sportif 1.5
Posts: 2,458
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 18 Post(s)
Quote:
Originally Posted by mooder View Post
The thing is that the spoke tension meter made by park tool is like 90$
Surely a nice tool to have for those of us doing the maintenance ourselves but in the amazon comments many user were saying it was practically useless and they could do a good / faster job by pitching the spoke.
I am willing to spend the money on one but it's somewhat uber expensive for what it is (as always with park tools).
http://www.amazon.ca/Park-Tool-Spoke.../dp/B000OZDIGY
I got mine from Bike Hub Store for $72 USD :-). I guess I am just a tool using animal by nature, after 40+ years of buying Micrometers and Dial Indicators, and lathes and Milling Machines...72 was not a HUGE pile of $$ :-). Brandon said he bought a pile of them for a good price, hence the nice price :-)
Willbird is offline   Reply With Quote
Old 04-20-15, 03:25 PM   #19
Kopsis
Senior Member
 
Kopsis's Avatar
 
Join Date: Apr 2008
Location: St. Pete, Florida
Bikes:
Posts: 1,260
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Quote:
Originally Posted by noglider View Post
I just use feel. My question is: how much pitch variation is OK? I got as much as a minor third (musically speaking) difference between the lowest pitch and the highest pitch I found in the wheel I built most recently.
Tension increases as the square of frequency, so a minor third is about a 40% difference in tension. Certainly more than I like to see on my builds (unless we're talking DS vs. NDS).
Kopsis is offline   Reply With Quote
Old 04-20-15, 03:27 PM   #20
noglider 
aka Tom Reingold
 
noglider's Avatar
 
Join Date: Jan 2009
Location: West Village, New York City
Bikes: too many
Posts: 31,704
Mentioned: 221 Post(s)
Tagged: 0 Thread(s)
Quoted: 2576 Post(s)
Quote:
Originally Posted by Kopsis View Post
Tension increases as the square of frequency, so a minor third is about a 40% difference in tension. Certainly more than I like to see on my builds (unless we're talking DS vs. NDS).
Oh, good point about DS/NDS. I don't remember now, and the wheels are upstate, where I can't reach them until the weekend. What is a good guideline for maximum pitch deviation? Or am I asking the wrong question?
__________________
Tom Reingold, [email protected]
New York City and High Falls, NY
Blogs: The Experienced Cyclist; noglider's ride blog

"Don’t buy upgrades. Ride up grades." -Eddy Merckx

Please email me rather than PM'ing me. Thanks.
noglider is offline   Reply With Quote
Old 04-20-15, 03:57 PM   #21
Kopsis
Senior Member
 
Kopsis's Avatar
 
Join Date: Apr 2008
Location: St. Pete, Florida
Bikes:
Posts: 1,260
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 82 Post(s)
Quote:
Originally Posted by noglider View Post
Oh, good point about DS/NDS. I don't remember now, and the wheels are upstate, where I can't reach them until the weekend. What is a good guideline for maximum pitch deviation? Or am I asking the wrong question?
A minor second is about a 12% tension difference. A major second is about 26%. How much is too much depends on the build. With rims that start relatively true (untensioned) I can generally get all spokes on a side within 20%.
Kopsis is offline   Reply With Quote
Old 04-20-15, 04:03 PM   #22
Gresp15C
Senior Member
 
Gresp15C's Avatar
 
Join Date: Sep 2014
Bikes:
Posts: 1,612
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 227 Post(s)
What's the definition of a minor second? Two piccolos playing in unison.
Gresp15C is offline   Reply With Quote
Old 04-20-15, 05:04 PM   #23
RubeRad
Keepin it Wheel
 
RubeRad's Avatar
 
Join Date: Aug 2011
Location: San Diego
Bikes: Surly CrossCheck, Moto Fantom29 ProSL hardtail
Posts: 7,029
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Quote:
Originally Posted by Gresp15C View Post
What's the definition of a minor second? Two piccolos playing in unison.
How do you get two flutes to play in unison? Shoot one. How do you get one flute not to play out of tune? Shoot the other one.

To answer the OP's specific question, what frequency is A or G? Concert a for tuning an orchestra is (nowadays) 440Hz. An octave lower would be 220, another octave lower would be 110, etc. G's would be similar, according to the table you linked.

So I bet the author of that article was referring to A=110 and G=98; it's pretty unlikely that your wheel is off by a whole octave unless it is seriously jacked up.
RubeRad is online now   Reply With Quote
Old 04-21-15, 06:11 AM   #24
noglider 
aka Tom Reingold
 
noglider's Avatar
 
Join Date: Jan 2009
Location: West Village, New York City
Bikes: too many
Posts: 31,704
Mentioned: 221 Post(s)
Tagged: 0 Thread(s)
Quoted: 2576 Post(s)
@Kopsis, thank you. I'll see if I can get tension within one major second. Maybe I'm there already.
__________________
Tom Reingold, [email protected]
New York City and High Falls, NY
Blogs: The Experienced Cyclist; noglider's ride blog

"Don’t buy upgrades. Ride up grades." -Eddy Merckx

Please email me rather than PM'ing me. Thanks.
noglider is offline   Reply With Quote
Old 04-21-15, 06:49 AM   #25
Jarrett2
Senior Member
 
Jarrett2's Avatar
 
Join Date: May 2013
Location: DFW
Bikes: Steel 1x's
Posts: 4,095
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 611 Post(s)
I'm a 30+ year musician with a good ear and I've found pitch alone to be misleading when checking spokes.

Not sure what all factors play into it, but I've found that two different spokes can be at different pitches and still measure out similarly on my Park tool.

I do regularly spin the wheel and let my thumbnail strike the spokes and listen for differences and then check there.
Jarrett2 is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 07:01 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    get answers from real people!
Click to start entering your question.
I HAVE A QUESTION